1: J Nutr. 2004 May;134(5):1051-1057.
A Solid Dietary Fat Containing Fish Oil Redistributes Lipoprotein Subclasses
without Increasing Oxidative Stress in Men.
Tholstrup T, Hellgren LI, Petersen M, Basu S, Straarup EM, Schnohr P, Sandstrom
B.
Centre for Advanced Food Studies, Department Human Nutrition, The Royal
Veterinary and Agricultural University, DK-1958 Frederiksberg, Denmark.
Biocentrum-DTU, Biochemistry and Nutrition, Technical University of Denmark,
Lyngby, Denmark. Section of Geriatrics and Clinical Nutrition Research, Faculty
of Medicine, Uppsala University, Uppsala, Sweden. The Copenhagen City Heart
Study, Bispebjerg University Hospital, Copenhagen, Denmark.
There is a demand and need for healthy solid dietary fats. However, synthetic
fats can be tailored to contain specific physiologic properties. Our goal was to
design dietary solid test fats that would be both beneficial to the atherogenic
lipid profile and stable against lipid peroxidation. Sixteen men (age 35-75 y)
substituted 80 g of their normal dietary fat intake with test fat for two
periods of 21 d each in a double-blind, randomized, crossover study. Although
solid, both test fats were low in cholesterol-raising SFA. Test fat "F"
contained 5 g/100 g long chain (n-3) fatty acids matched by oleic acid in test
fat "O." Plasma total triacylglycerol (TAG), VLDL TAG, cholesterol in VLDL, and
intermediate density lipoproteins (IDL) were lower (P < 0.05), whereas
apolipoprotein (apo) B of the large LDL-2 (d = 1031-1042 g/L) subclass, and
cholesterol of HDL(2b) subclass, were higher after intake of F than O fat (P <
0.05). There was no difference in the effect on in vivo oxidation measured as
the ratio of plasma isoprostanes F(2) to arachidonic acid and urinary
isoprostanes, whereas the vitamin E activity/plasma total lipids ratio was
higher after intake of F than O (P = 0.008). In conclusion, a solid dietary fat
containing (n-3) PUFA decreased plasma TAG, VLDL, and IDL cholesterol, and
redistributed lipoprotein subclasses in LDL and HDL, with a higher concentration
of the larger and less atherogenic subfractions. These changes took place
without an increase in oxidative stress as measured by in vivo markers.
PMID: 15113944 [PubMed]
2: Am J Clin Nutr. 2004 May;79(5):907S-12S.
Role of calcium and dairy products in energy partitioning and weight management.
Zemel MB.
University of Tennessee, Knoxville.
Dietary calcium plays a pivotal role in the regulation of energy metabolism
because high-calcium diets attenuate adipocyte lipid accretion and weight gain
during the overconsumption of an energy-dense diet and increase lipolysis and
preserve thermogenesis during caloric restriction, which thereby markedly
accelerates weight loss. Intracellular Ca(2+) plays a key regulatory role in
adipocyte lipid metabolism and triacylglycerol storage; increased intracellular
Ca(2+) results in the stimulation of lipogenic gene expression and lipogenesis
and the suppression of lipolysis, which results in increased lipid filling and
increased adiposity. Moreover, the increased calcitriol produced in response to
low-calcium diets stimulates adipocyte Ca(2+) influx and, consequently, promotes
adiposity, whereas higher-calcium diets inhibit lipogenesis, inhibit
diet-induced obesity in mice, and promote lipolysis, lipid oxidation, and
thermogenesis. Notably, dairy sources of calcium markedly attenuate weight and
fat gain and accelerate fat loss to a greater degree than do supplemental
sources of calcium. This augmented effect of dairy products relative to
supplemental calcium is likely due to additional bioactive compounds, including
the angiotensin-converting enzyme inhibitors and the rich concentration of
branched-chain amino acids in whey, which act synergistically with calcium to
attenuate adiposity. These concepts are confirmed by epidemiologic data and
recent clinical trials, which indicate that diets that include >/=="
BORDER="0">3 daily servings of dairy products result in significant reductions
in adipose tissue mass in obese humans in the absence of caloric restriction and
markedly accelerate weight and body fat loss secondary to caloric restriction
compared with diets low in dairy products. These data indicate an important role
for dairy products in both the prevention and treatment of obesity.
PMID: 15113738 [PubMed]
3: Am J Clin Nutr. 2004 May;79(5):899S-906S.
Is a calorie a calorie?
Buchholz AC, Schoeller DA.
Department of Nutritional Sciences, University of Wisconsin-Madison.
The aim of this review was to evaluate data regarding potential thermodynamic
mechanisms for increased rates of weight loss in subjects consuming diets high
in protein and/or low in carbohydrate. Studies that compared weight loss and
energy expenditure in adults consuming diets high in protein and/or low in
carbohydrate with those in adults consuming diets low in fat were reviewed. In
addition, studies that measured the metabolizable energy of proteins, fats, and
carbohydrates were reviewed. Diets high in protein and/or low in carbohydrate
produced an approximately 2.5-kg greater weight loss after 12 wk of treatment.
Neither macronutrient-specific differences in the availability of dietary energy
nor changes in energy expenditure could explain these differences in weight
loss. Thermodynamics dictate that a calorie is a calorie regardless of the
macronutrient composition of the diet. Further research on differences in the
composition of weight loss and on the influence of satiety on compliance with
energy-restricted diets is needed to explain the observed increase in weight
loss with diets high in protein and/or low in carbohydrate.
PMID: 15113737 [PubMed]
4: Am J Physiol Endocrinol Metab. 2004 Apr 27 [Epub ahead of print]
Longitudinal changes in energy expenditure and body composition in obese women
with normal and impaired glucose tolerance.
Okereke NC, Huston-Presley L, Amini SB, Kalhan S, Catalano PM.
Department of Reproductive Biology, Case Western Reserve University at
MetroHealth Medical Center, Cleveland, OH, USA.
Our primary objective was to evaluate the changes in energy expenditure and body
composition in women with normal glucose tolerance (NGT) and gestational
diabetes (GDM). A secondary objective was to examine the relationship between
maternal leptin and nutrient metabolism. Fifteen obese women 8 with NGT and 7
with GDM were evaluated prior to conception (P) at 12-14 weeks (E) and 34-36
weeks (L). Energy expenditure and glucose and fat metabolism were measured using
indirect calorimetry. Basal hepatic glucose production was measured using [6,6
(2)H2] glucose and insulin sensitivity by the euglycemic clamp. There was a
significant increase (6.6 kg, p=0.0001) in fat mass (FM) from time P to L. There
was a 30% (p=0.0001) increase in basal VO2 (ml/min). There were no significant
changes in carbohydrate oxidation during fasting or storage from P to L. There
was, however, a significant (p=0.0001) 150% increase in basal fat oxidation
(mg/min) from P to L. Under hyperinsulinemic conditions there were similar 25%
increases in VO2 (p=0.0001) from P to L in both groups. Because of the
significant increases in insulin resistance from P to L, there was a significant
(p=0.0001) decrease in carbohydrate oxidation and storage. There was a net
change from lipogenesis to lipolysis, i.e. fat oxidation (30- 40 mg/min,
p=0.0001) from P to L. Serum leptin concentrations had a significant positive
correlation with fat oxidation at time E (r=0.76, p=0.005) and L (r=0.72,
p=0.009). Pregnancy in obese women is associated with significant increases in
fat mass, basal metabolic rate and an increased reliance on lipids both in the
basal state and during the clamp. These modifications are similar in women with
NGT and GDM. The increased reliance on fat metabolism is accompanied by a
concomitant decrease in carbohydrate metabolism during hyperinsulinemia. The
increase in fat oxidation may be related to increased maternal serum leptin.
PMID: 15113705 [PubMed]
5: Int J Obes Relat Metab Disord. 2004 Apr 27 [Epub ahead of print]
Resistance to the orexigenic effect of ghrelin in dietary-induced obesity in
mice: reversal upon weight loss.
Perreault M, Istrate N, Wang L, Nichols AJ, Tozzo E, Stricker-Krongrad A.
1Metabolic Diseases Biology Department, Millennium Pharmaceuticals Inc.,
Cambridge, MA, USA.
BACKGROUND:: Ghrelin, an endogenous ligand for growth hormone secretagogue
receptor (GHS-R), is known to increase food intake in lean humans and rodents.
In addition, ghrelin levels are increased by fasting in lean rodents and are
elevated before meals in humans, suggesting an important role for ghrelin in
meal initiation. However, in obese human, circulating ghrelin levels were found
to be significantly reduced as compared to lean individuals. OBJECTIVES:: To
evaluate whether circulating ghrelin levels, as well as ghrelin sensitivity, are
decreased in obese individuals in order to limit its effect on food intake.
DESIGN:: Lean C57BL/6J mice fed a chow, a low- (LFD) or a high-fat diet (HFD)
were used to determine ghrelin regulation and secretion as well as ghrelin
sensitivity. MEASUREMENTS:: Plasma ghrelin levels were measured in low- and
high-fat fed mice. Ghrelin-induced food intake was measured in chow, low- and
high-fat fed mice. RESULTS:: We measured ghrelin levels in lean and diet-induced
obese mice, fed on an LFD or an HFD, respectively. We observed that not only
ghrelin secretion was reduced in obese mice but its diurnal regulation was also
lost. In addition, we failed to observe any change in ghrelin secretion upon
fasting and refeeding. Moreover, we observed that the sensitivity to the
orexigenic effects of exogenous ghrelin was reduced in obese mice when compared
to lean mice fed a chow or a LFD. The insensitivity of obese mice to ghrelin was
improved upon weigh loss. CONCLUSION:: Altogether, these results indicate that
ghrelin secretion and regulation is impaired in dietary-induced obesity in mice
and suggest that ghrelin inhibition could prevent weight regain after weight
loss.International Journal of Obesity advance online publication, 27 April 2004;
doi:10.1038/sj.ijo.0802640
PMID: 15111983 [PubMed]
6: Diabetes Care. 2004 May;27(5):1077-80.
Orlistat augments postprandial increases in glucagon-like peptide 1 in obese
type 2 diabetic patients.
Damci T, Yalin S, Balci H, Osar Z, Korugan U, Ozyazar M, Ilkova H.
Istanbul University Cerrahpasa Medical School, Department of Internal Medicine,
Division of Endocrinology Diabetes and Metabolism, Istanbul, Turkey.
tdamci@superonline.com
OBJECTIVE: Orlistat leads to improved glycemic control in obese type 2 diabetic
patients, which is attributed to decreased insulin resistance associated with
weight loss. Glucagon-like peptide 1 (GLP-1) and glucose-dependent
insulinotropic peptide (GIP) are gut hormones that are secreted in response to
food intake, and they both stimulate insulin secretion. Orlistat decreases fat
absorption and increases intestinal fat content, which may lead to increased
secretion of these peptides. In this pilot study, we tested the hypothesis that
increased levels of these intestinal hormones may be involved in the improvement
of postprandial hyperglycemia observed previously with orlistat in type 2
diabetic patients. RESEARCH DESIGN AND METHODS: A total of 29 type 2 diabetic
patients, who were not taking insulin or alpha-glucosidase inhibitors, were
enrolled in the study. On a crossover and single-blind design, after an
overnight fasting, the patients received 120-mg orlistat or placebo capsules,
followed by a standard 600-kcal mixed meal that contained 38% fat. At baseline
and 60 min after the meal, blood samples were obtained for the measurement of
GLP-1, GIP, insulin, C-peptide, triglycerides, free fatty acids, and glucose.
RESULTS: All measured parameters increased significantly in response to the
mixed meal compared with baseline, both with orlistat or placebo. When compared
with the placebo, the orlistat administration resulted in a significantly
enhanced postprandial increase in GLP-1 and C-peptide levels and attenuated the
postprandial rise in glucose and triglycerides. CONCLUSIONS: The results of this
study suggest that apart from decreasing insulin resistance as a result of
weight loss, orlistat may increase postprandial GLP-1 levels, thereby enhancing
the insulin secretory response to the meal and blunting the postprandial rise in
glucose in type 2 diabetic patients. Increased GLP-1 levels, which lead to
decreased food intake, may also contribute to the weight loss that is associated
with the use of this drug.
PMID: 15111524 [PubMed]
7: Sports Med. 2004;34(5):317-327.
Macronutrient Considerations for the Sport of Bodybuilding.
Lambert CP, Frank LL, Evans WJ.
Nutrition, Metabolism, and Exercise Laboratory, Donald W. Reynolds Center on
Aging, Department of Geriatrics, University of Arkansas for Medical Sciences and
Geriatric Research, Education and Clinical Center, Central Arkansas Veterans
Healthcare System, Little Rock, Arkansas, USA.
Participants in the sport of bodybuilding are judged by appearance rather than
performance. In this respect, increased muscle size and definition are critical
elements of success. The purpose of this review is to evaluate the literature
and provide recommendations regarding macronutrient intake during both
'off-season' and 'pre-contest' phases. Body builders attempt to increase muscle
mass during the off-season (no competitive events), which may be the great
majority of the year. During the off-season, it is advantageous for the
bodybuilder to be in positive energy balance so that extra energy is available
for muscle anabolism. Additionally, during the off-season, adequate protein must
be available to provide amino acids for protein synthesis. For 6-12 weeks prior
to competition, body builders attempt to retain muscle mass and reduce body fat
to very low levels. During the pre-contest phase, the bodybuilder should be in
negative energy balance so that body fat can be oxidised. Furthermore, during
the pre-contest phase, protein intake must be adequate to maintain muscle mass.
There is evidence that a relatively high protein intake (~30% of energy intake)
will reduce lean mass loss relative to a lower protein intake (~15% of energy
intake) during energy restriction. The higher protein intake will also provide a
relatively large thermic effect that may aid in reducing body fat. In both the
off-season and pre-contest phases, adequate dietary carbohydrate should be
ingested (55-60% of total energy intake) so that training intensity can be
maintained. Excess dietary saturated fat can exacerbate coronary artery disease;
however, low-fat diets result in a reduction in circulating testosterone. Thus,
we suggest dietary fats comprise 15-20% of the body builders' off-season and
pre-contest diets.Consumption of protein/amino acids and carbohydrate
immediately before and after training sessions may augment protein synthesis,
muscle glycogen resynthesis and reduce protein degradation. The optimal rate of
carbohydrate ingested immediately after a training session should be 1.2
g/kg/hour at 30-minute intervals for 4 hours and the carbohydrate should be of
high glycaemic index. In summary, the composition of diets for body builders
should be 55-60% carbohydrate, 25-30% protein and 15-20% of fat, for both the
off-season and pre-contest phases. During the off-season the diet should be
slightly hyperenergetic (~15% increase in energy intake) and during the
pre-contest phase the diet should be hypoenergetic (~15% decrease in energy
intake).
PMID: 15107010 [PubMed]
8: Ter Arkh. 2004;76(2):40-4.
[In Process Citation]
[Article in Russian]
[No authors listed]
AIM: To study morphological alterations in small intestinal wall in patients
with chronic cardiac failure (CCF) of various severity and their relations with
functional condition of the small intestine. MATERIAL AND METHODS: 63 patients
(mean age 58.7 years) entered an open cohort study. By CCF and body mass index
(BMI) the patients were divided into 4 groups. Estimation of ejection fraction
(EF), BMI and lean body mass (LBM) was made in all the patients as well as
functional intestinal activity was assessed by fat excretion and fecal protein.
Small intestinal biopsies were made endoscopically for collagen quantitation.
RESULTS: A rise in collagen content in the small intestine correlated with
severity of CCF. In patients free of CCF relative area of collagen averaged
12.8%, in CCF FC I-II--16.5%, in CCF FC III-IV with cachexia--32.4%. Greater
fibrosis of the small intestine corresponded to greater malabsorption. A 3-fold
increase in collagen area led to a 2-3-fold growth in protein and fat loss with
feces. In CCF, LBM was subnormal while body mass reduction correlated with
relative collagen area. CONCLUSION: Morphofunctional changes of the small
intestine developing in parallel with CCF severity lead to a significant loss in
basic nutrients, regression of LBM and development of protein-energy
insufficiency in patients with CCF.
PMID: 15106413 [PubMed]
9: J Clin Endocrinol Metab. 2004 Apr;89(4):1753-9.
Further lowering of muscle lipid oxidative capacity in obese subjects after
biliopancreatic diversion.
Fabris R, Mingrone G, Milan G, Manco M, Granzotto M, Dalla Pozza A, Scarda A,
Serra R, Greco AV, Federspil G, Vettor R.
Endocrine-Metabolic Laboratory, Internal Medicine, Department of Medical and
Surgical Sciences, University of Padova, 35128 Padova, Italy.
A reduced lipid oxidative capacity is considered a risk factor for the
development of obesity, but a further impairment of lipid oxidative capacity is
observed after weight loss. We aimed to define the mechanisms underlying this
phenomenon in skeletal muscle and in particular to study the mitochondrial and
peroxisomal lipid oxidative pathways. Thus we measured intramyocellular
triglyceride content (IMTG) and the expression of genes of lipid oxidation
[peroxisome proliferator-activated receptor-alpha, carnitine
palmitoyltransferase 1B, and acyl-coenzyme A (acyl-CoA) oxidase 1] and synthesis
(acetyl-CoA carboxylase B) using RT-PCR analysis in muscle biopsies of morbidly
obese patients before and after biliopancreatic diversion. Weight reduction
significantly decreased IMTG while increasing insulin sensitivity, measured by
euglycemic hyperinsulinemic clamp. Moreover, an increase in glucose and a
decline in lipid oxidation, as assessed by respiratory chamber, were observed.
Weight loss reduced the expression of peroxisome proliferator-activated
receptor-alpha (-46.7%), carnitine palmitoyltransferase 1B (-43.1%), acyl-CoA
oxidase 1 (-37.8%), and acetyl-CoA carboxylase B (-48.7%). Our results indicate
that a defect of both peroxisomal and mitochondrial oxidative pathways at the
muscular level may contribute to the reduced fat oxidation in obese subjects
after biliopancreatic diversion. They also suggest that a depression of the de
novo lipogenesis may account for IMTG depletion.
PMID: 15070941 [PubMed]
10: J Bone Miner Res. 2004 May;19(5):830-40.
Oxysterols regulate differentiation of mesenchymal stem cells: pro-bone and
anti-fat.
Kha HT, Basseri B, Shouhed D, Richardson J, Tetradis S, Hahn TJ, Parhami F.
Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles,
California, USA.
Pluripotent mesenchymal stem cells can undergo lineage-specific differentiation
in adult organisms. However, understanding of the factors and mechanisms that
drive this differentiation is limited. We show the novel ability of specific
oxysterols to regulate lineage-specific differentiation of mesenchymal stem
cells into osteogenic cells while inhibiting their adipogenic differentiation.
Such effects may have important implications for intervention with osteoporosis.
INTRODUCTION: Oxysterols are products of cholesterol oxidation and are formed in
vivo by a variety of cells including osteoblasts. Novel pro-osteogenic and
anti-adipogenic effects of specific oxysterols on pluripotent mesenchymal cells
are demonstrated in this report. Aging and osteoporosis are associated with a
decrease in the number and activity of osteoblastic cells and a parallel
increase in the number of adipocytic cells. MATERIALS AND METHODS: The M2-10B4
pluripotent marrow stromal cell line, as well as several other mesenchymal cell
lines and primary marrow stromal cells, was used to assess the effects of
oxysterols. All results were analyzed for statistical significance using ANOVA.
RESULTS AND CONCLUSION: Pro-osteogenic and anti-adipogenic effects of specific
oxysterols were assessed by the increase in early and late markers of osteogenic
differentiation, including alkaline phosphatase activity, osteocalcin mRNA
expression and mineralization, and the decrease in markers of adipogenic
differentiation including lipoprotein lipase and adipocyte P2 mRNA expression
and adipocyte formation. Complete osteogenic differentiation of M2 cells into
cells expressing early and late markers of differentiation was achieved only
when using combinations of specific oxysterols, whereas inhibition of
adipogenesis could be achieved with individual oxysterols. Oxysterol effects
were in part mediated by extracellular signal-regulated kinase and enzymes in
the arachidonic acid metabolic pathway, i.e., cyclo-oxygenase and phospholipase
A(2). Furthermore, we show that these specific oxysterols act in synergy with
bone morphogenetic protein 2 in inducing osteogenic differentiation. These
findings suggest that oxysterols may play an important role in the
differentiation of mesenchymal stem cells and may have significant, previously
unrecognized, importance in stem cell biology and potential therapeutic
interventions.
PMID: 15068507 [PubMed]
11: Mech Ageing Dev. 2004 Apr;125(4):297-304.
Effects of testosterone on body composition of the aging male.
Mudali S, Dobs AS.
Johns Hopkins University School of Medicine, Baltimore, MD 21208, USA.
The aging process is accompanied by significant changes in body composition
characterized by decreased fat free mass and increased and redistributed fat
mass. Muscle loss results from the atrophy of muscle fibers and decreased
synthesis of muscle proteins. Increased number of adipocytes and fat
accumulation in non-adipose tissue leads to adiposity. These changes can impose
functional limitations and increase morbidity. In men, declining testosterone
levels that occur with aging can be a contributing factor to these changes.
Studies in hypogonadal men have shown that testosterone replacement is effective
in increasing muscle mass and strength and decreasing fat mass. The molecular
mechanisms of testosterone's influence on muscle and adipose are not fully
elucidated. However, testosterone appears to stimulate IGF-1 expression directly
and indirectly leading to increased muscle protein synthesis and growth. It may
also counter the inhibitory effects of myostatin, cytokines, and
glucocorticoids. The predominant effects of testosterone on fat mass are
increased lipolysis and decreased adipogenesis. Current evidence suggests that
testosterone replacement may be effective in reversing age-dependent body
composition changes and associated morbidity. However, hypogonadism must be
diagnosed carefully, and therapy should be monitored regularly in order to avoid
the adverse effects associated with testosterone supplementation.
PMID: 15063106 [PubMed]
12: J Med Assoc Thai. 2004 Feb;87(2):166-72.
Improvement of fat redistribution, insulin resistance and hepatic fatty
infiltration in HIV-associated lipodystrophy syndrome by pioglitazone: a case
report.
Prasithsirikul W, Bunnag P.
Bamrasnaradura Institute, Nonthaburi 11000, Thailand.
HIV-associated lipodystrophy syndrome is a syndrome occurring in HIV-infected
patients who were treated with highly-active antiretroviral therapy (HAART),
especially regimen containing protease inhibitors. The syndrome consists of fat
redistribution, with loss of subcutaneous fat and increase in visceral fat, and
metabolic disturbances, including glucose intolerance or overt diabetes and
dyslipidemia. No standard treatment has been established for this syndrome.
Pioglitazone is an oral antidiabetic agent that acts primarily on adipose tissue
to reduce insulin resistance. The authors report a 50-year old HIV-infected
woman who developed HIV-associated lipodystrophy syndrome after 3 months of
HAART. She had significant weight loss with obvious loss of subcutaneous fat,
together with development of hypertension, diabetes and dyslipidemia. After
treatment with 30 milligrams of pioglitazone daily, her body weight increased
within the first month of treatment. Subcutaneous fat loss was restored.
Improvement in glycemic and lipid control was also noted. CT scan of the abdomen
revealed that fatty infiltration in the liver was markedly decreased. Visceral
fat as assessed by CT scan had also decreased. Pioglitazone appeared to have
beneficial effects in this patient.
Publication Types:
Case Reports
PMID: 15061300 [PubMed]
13: Endocrinology. 2004 Apr 1 [Epub ahead of print]
Estrogen and raloxifene modulate leptin and its receptor in hypothalamus and
adipose tissue from ovariectomized rats.
Meli R, Pacilio M, Mattace Raso G, Esposito E, Coppola A, Nasti A, Di Carlo C,
Nappi C, Di Carlo R.
Department of Experimental Pharmacology, *Department of Obstetrics and
Gynaecology, University of Naples Federico II, Naples, Italy.
Obesity, from declining estrogen levels after menopause, increases the risk of
heart disease, diabetes, and hypertension. Ovariectomy in rats is a good model
of estrogen insufficiency. The ensuing mild obesity is useful to study how
hypoestrogenism alters adiposity. This study aims to examine the hypothesis that
in ovariectomized rats modification in estrogen levels or a treatment with a
selective estrogen receptor modulator raloxifene (RAL) alters leptinemia and
modulates leptin receptor (Ob-R) abundance in hypothalamus and white adipose
tissue, in replay to modification of adipose status induced by hypoestrogenism.
Mid- and long-term studies (7 and 22 weeks) were conducted to monitor the change
of leptinemia in rats after estrogen loss by ovariectomy (OVX), estrogen
replacement by 17-beta-estradiol (OVX+E2) or RAL treatment (OVX+RAL). Leptin was
significantly higher in OVX rats vs. controls, in a time dependent manner. This
effect was reversed both by E2 or RAL treatment at 7 (P < 0.05) and 22 weeks (P
< 0.001). Moreover, E2- or RAL-treatment reverted ovariectomy-induced increase
of food intake, body weight and fat mass content; the modifications of serum
parameters were examined to evaluate the different lipid profile. We also
evaluated Ob-R expression in hypothalamus and adipose tissue by Western blot
analysis. The expression of the long functional isoform (Ob-Rb) increased at 7
weeks only in adipose tissue and decreased at 22 weeks in OVX rats in both
tissues and these effects were reversed by E2 or RAL treatment. We provide
evidence that central and peripheral Ob-Rb expression is related to modification
of estrogen levels.
PMID: 15059958 [PubMed]
14: Eur J Nutr. 2004 Mar;43 Suppl 1:I6-I11.
What are the health effects of fat?
Wahrburg U.
Fachhochschule Munster, Fachbereich Oecotrophologie, Corrensstr. 25, 48149,
Munster, Germany, uwahrburg@fh-muenster.de
In order to answer the question which health benefits are to be expected from
dietary fat, we have to differentiate between different kinds of fat with
varying fatty acid composition. Saturated fatty acids are commonly judged to
have a negative health impact as they lead to increased serum cholesterol levels
and a higher risk of coronary heart disease. Therefore, all recommendations
stress the importance to limit the intake of saturated fatty acids.
Monounsaturated fatty acids, on the other hand, have a positive impact on the
serum lipid profile, lead to decreased LDL-oxidation and favorably influence the
metabolism of diabetics. However, it is essential that monounsaturated fatty
acids be mainly supplied by plant oils like rape seed or olive oil and not by
foods that are simultaneously rich in saturated fatty acids. Concerning
polyunsaturated fatty acids, it is important to increase the supply of n-3 fatty
acids (ratio of n-6:n-3: about 5:1) as there is substantial evidence for their
protective effects. If the fatty acid composition of the diet is optimized, even
a total dietary fat content of 35% of total energy intake can be adequate as
long as there is enough physical activity and the diet is rich in plant-derived
foods like vegetables, fruits, cereals, potatoes, beans and legumes.
PMID: 15052493 [PubMed]
15: J Nutr. 2004 Apr;134(4):968S-73S.
Dietary protein impact on glycemic control during weight loss.
Layman DK, Baum JI.
Department of Food Science and Human Nutrition, University of Illinois
Urbana-Champaign, Urbana, IL 61801, USA. dlayman@uiuc.edu
Diets with higher protein (1.5 g x kg(-1) x d(-1)) and reduced carbohydrates
(120 to 200 g/d) appear to enhance weight loss due to a higher loss of body fat
and reduced loss of lean body mass. While studies of prolonged use of moderate
protein diets are not available, short-term studies report beneficial effects
associated with increased satiety, increased thermogenesis, sparing of muscle
protein loss, and enhanced glycemic control. Combined impacts of a moderate
protein diet are likely derived from lower carbohydrates resulting in lower
postprandial increase in blood glucose and lower insulin response, and higher
protein providing increased BCAA leucine levels and gluconeogenic substrates. A
key element in the diet appears to be the higher intake of BCAA leucine with
unique regulatory actions on muscle protein synthesis, modulation of the insulin
signal, and sparing of glucose use by stimulation of the glucose-alanine cycle.
This review focuses on the contributions of leucine and the BCAA to regulation
of muscle protein synthesis and glycemic control.
Publication Types:
Review
Review, Tutorial
PMID: 15051856 [PubMed]
16: J Nutr. 2004 Apr;134(4):880-5.
Very low-carbohydrate and low-fat diets affect fasting lipids and postprandial
lipemia differently in overweight men.
Sharman MJ, Gomez AL, Kraemer WJ, Volek JS.
Department of Kinesiology, University of Connecticut, Storrs, CT 06269-1110,
USA. matthew.sharman@uconn.edu
Hypoenergetic very low-carbohydrate and low-fat diets are both commonly used for
short-term weight loss; however, few studies have directly compared their effect
on blood lipids, with no studies to our knowledge comparing postprandial
lipemia, an important independently identified cardiovascular risk factor. The
primary purpose of this study was to compare the effects of a very
low-carbohydrate and a low-fat diet on fasting blood lipids and postprandial
lipemia in overweight men. In a balanced, randomized, crossover design,
overweight men (n = 15; body fat >25%; BMI, 34 kg/m(2)) consumed 2 experimental
diets for 2 consecutive 6-wk periods. One was a very low-carbohydrate (<10%
energy as carbohydrate) diet and the other a low-fat (<30% energy as fat) diet.
Blood was drawn from fasting subjects on separate days and an oral fat tolerance
test was performed at baseline, after the very low-carbohydrate diet period, and
after the low-fat diet period. Both diets had the same effect on serum total
cholesterol, serum insulin, and homeostasis model analysis-insulin resistance
(HOMA-IR). Neither diet affected serum HDL cholesterol (HDL-C) or oxidized LDL
(oxLDL) concentrations. Serum LDL cholesterol (LDL-C) was reduced (P < 0.05)
only by the low-fat diet (-18%). Fasting serum triacylglycerol (TAG), the
TAG/HDL-C ratio, and glucose were significantly reduced only by the very
low-carbohydrate diet (-44, -42, and -6%, respectively). Postprandial lipemia
was significantly reduced when the men consumed both diets compared with
baseline, but the reduction was significantly greater after intake of the very
low-carbohydrate diet. Mean and peak LDL particle size increased only after the
very low-carbohydrate diet. The short-term hypoenergetic low-fat diet was more
effective at lowering serum LDL-C, but the very low-carbohydrate diet was more
effective at improving characteristics of the metabolic syndrome as shown by a
decrease in fasting serum TAG, the TAG/HDL-C ratio, postprandial lipemia, serum
glucose, an increase in LDL particle size, and also greater weight loss (P <
0.05).
Publication Types:
Clinical Trial
Randomized Controlled Trial
PMID: 15051841 [PubMed]
17: J Am Coll Nutr. 2004 Apr;23(2):102-7.
Long-term nutritional and digestive consequences of pelvic radiation.
Pia de la Maza M, Agudelo GM, Yudin T, Gattas V, Barrera G, Bunout D, Hirsch S.
Institute of Nutrition and Food Technology (INTA)-University of Chile, Santiago,
Chile. mpmaza@uec.inta.uchile.cl
OBJECTIVE: To study long-term changes in nutritional status and gastrointestinal
(GI) functions of 15 women previously treated with radiotherapy for
gynecological cancer. Two years prior to this research, these patients had been
assessed twice: before external radiotherapy and 5 weeks later, at the
completion of the external dose (45-50 Gy). METHODS: Each patient was given
complete clinical evaluation, consisting of dietary, physical activity and
digestive symptoms questionnaires. Blood was drawn for routine clinical
laboratory tests (hemoglobin, white blood cell count, creatinine, lipoproteins,
glucose, total proteins, albumin, and C reactive protein). Body composition was
assessed by classical anthropometric indicators and double beam X-ray
absorptiometry (DEXA), while muscle strength was measured through a hand
dynamometer. Resting energy expenditure (REE), obtained by indirect calorimetry,
was subtracted from energy ingestion, derived from dietary records, to calculate
energy balance. RESULTS: This third evaluation included fifteen patients. A
significant increase in body mass index (BMI), % body fat and waist
circumference were observed in comparison to earlier evaluations. The lean
compartment decreased significantly, and REE descended in parallel. Meanwhile,
total energy, fat and protein intake increased, compared to previous
measurements. The changes in bowel habits observed during radiotherapy persisted
at this third evaluation, with the exception of diarrhea, which was less
reported. Abdominal bloating and rectal symptoms were the most prevalent
complaints. CONCLUSIONS: After radiation treatment for gynecological cancer,
patients gained more body fat than expected in Chilean women around menopause.
In spite of high protein ingestion, the loss of fat-free mass observed during
radiation treatment was not recovered along with weight increase. This is
probably associated with infrequent physical activity, both during and after
treatment, and hyperphagia.
PMID: 15047675 [PubMed]
18: Diabetes. 2004 Apr;53(4):1007-19.
A role for the malonyl-CoA/long-chain acyl-CoA pathway of lipid signaling in the
regulation of insulin secretion in response to both fuel and nonfuel stimuli.
Roduit R, Nolan C, Alarcon C, Moore P, Barbeau A, Delghingaro-Augusto V,
Przybykowski E, Morin J, Masse F, Massie B, Ruderman N, Rhodes C, Poitout V,
Prentki M.
Molecular Nutrition Unit, Department of Nutrition, University of Montreal and
the Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada.
The malonyl-CoA/long-chain acyl-CoA (LC-CoA) model of glucose-induced insulin
secretion (GIIS) predicts that malonyl-CoA derived from glucose metabolism
inhibits fatty acid oxidation, thereby increasing the availability of LC-CoA for
lipid signaling to cellular processes involved in exocytosis. For directly
testing the model, INSr3 cell clones overexpressing malonyl-CoA decarboxylase in
the cytosol (MCDc) in a tetracycline regulatable manner were generated, and
INS(832/13) and rat islets were infected with MCDc-expressing adenoviruses. MCD
activity was increased more than fivefold, and the malonyl-CoA content was
markedly diminished. This was associated with enhanced fat oxidation at high
glucose, a suppression of the glucose-induced increase in cellular free fatty
acid (FFA) content, and reduced partitioning at elevated glucose of exogenous
palmitate into lipid esterification products. MCDc overexpression, in the
presence of exogenous FFAs but not in their absence, reduced GIIS in all
beta-cell lines and in rat islets. It also markedly curtailed the stimulation of
insulin secretion by other fuel and nonfuel secretagogues. In the absence of
MCDc overexpression, the secretory responses to all types of secretagogues were
amplified by the provision of exogenous fatty acids. In the presence of
exogenous FFAs, the fatty acyl-CoA synthetase inhibitor triacsin C reduced
secretion in response to glucose and nonfuel stimuli. The data show the
existence of important links between the metabolic coupling factor malonyl-CoA,
the partitioning of fatty acids, and the stimulation of insulin secretion to
both fuel and nonfuel stimuli.
PMID: 15047616 [PubMed]
19: Physiol Res. 2004;53(2):229-34.
Quantification of intra-abdominal fat during controlled weight reduction:
assessment using the water-suppressed breath-hold MRI technique.
Tintera J, Harantova P, Suchanek P, Dvorakova A, Adamova M, Hajek M, Poledne R.
Institute of Clinical and Experimental Medicine, Videnska 1958/59, 140 00 Prague
4, Czech Republic. jati@medicon.cz
A group of 14 healthy female subjects was studied using MRI during 2 months of
life-style intervention. A series of 21 water-suppressed images was used to
determine the intra-abdominal fat volume before and after the controlled loss of
weight. The average weight decrease was 8.2 %, but the average relative loss of
visceral fat was 20.3 %, whereas subcutaneous fat decreased by 13.4 %. A small
but significant increase of insulin sensitivity (decrease in fasting insulin and
blood glucose) was observed, but no changes in lipoprotein parameters were
demonstrated. There was a significant negative correlation (r=-0.633, p=0.028)
between the relative abdominal fat decrease and the initial amount of
subcutaneous fat.
PMID: 15046562 [PubMed]
20: Metabolism. 2004 Apr;53(4):430-4.
Modest weight loss and reduction in waist circumference after medical treatment
are associated with favorable changes in serum adipocytokines.
Valsamakis G, McTernan PG, Chetty R, Al Daghri N, Field A, Hanif W, Barnett AH,
Kumar S.
Department of Diabetes and Endocrinology, Birmingham Heartlands Hospital,
Birmingham, UK.
Modest weight loss if maintained is associated with significant metabolic
benefits and reduction in cardiovascular risk. Adipose tissue secretes cytokines
believed to contribute to the pathogenesis of insulin resistance and
cardiovascular risk. We therefore observed the effect of modest weight loss on
serum adipocytokines and their relationship with changes in anthropometric and
metabolic parameters within a period of 6 months in the setting of a routine
obesity hospital clinic after various medical treatments. In this prospective,
nonrandomized, nonblinded observational study, patients were first given
treatment (sibutramine or orlistat) as decided by the treating clinician and
then allocated into 1 of 2 groups according to the treatment prescribed. The
first group included 21 Caucasian nondiabetic female subjects, with a mean
(+/-SD) age of 43 +/- 11 years and a mean body mass index (BMI) of 46 +/- 8.6
kg/m(2); subjects were treated with sibutramine 10 or 15 mg/d for weight loss.
The second group included 20 Caucasian nondiabetic female subjects, mean age 42
+/- 9 years and mean BMI 45.2 +/- 5.2 kg/m(2); orlistat was introduced after 1
month on a low-fat (5%) after
medical treatment in a routine obesity hospital clinic is associated with
improvements in insulin sensitivity and lipid profile. Modest weight loss is
also associated with potentially favourably changes in serum adipocytokines,
particularly in a rise of serum adiponectin. Reduction of waist circumference is
associated with a change in serum resistin.
PMID: 15045687 [PubMed]
21: Eur J Appl Physiol. 2004 Mar 26 [Epub ahead of print]
Hypohydration effects on thermoregulation during moderate exercise in the cold.
Kenefick RW, Mahood NV, Hazzard MP, Quinn TJ, Castellani JW.
Department of Kinesiology, The University of New Hampshire, New Hampshire Hall,
NH 03824, Durham, USA.
Hyperosmotic hypovolemia impairs vasoconstriction during sedentary cold
exposure. The purpose of this study was to determine whether hypohydration
alters thermoregulation and cardiovascular responses to exercise in cold air. On
four occasions, eight males [35.1 (2.7) years, 175.5 (3.1) cm, 73.3 (2.6) kg,
57.2 (2.6) ml kg(-1) min(-1) maximal oxygen uptake ( Vdot;O(2max)), 19.6 (2.4)%
fat] walked, in t-shirt, shorts, and shoes, at 50% Vdot;O(2max), for 60 min in
either a 4 degrees C (Cold) or a 25 degrees C (Temperate) environment in both
hypohydrated state (HYPO, -4% body mass) and euhydrated state (EU). During
exercise-cold stress, rectal temperature ( T(re)), mean weighted skin
temperature, heart rate (HR), cardiac output (CO), and stroke volume (SV) were
measured every 20 min. Mean weighted skin temperature values were not different
between HYPO and EU but were lower ( P<0.05) in Cold versus Temperate trials.
T(re) was not different ( P>0.05) between HYPO-Cold and EU-Cold. CO and SV were
not different within hydration states and were not different between Cold and
Temperate trials ( P<0.05). HR was not different between HYPO-Cold and EU-Cold.
These data demonstrate that moderate intensity exercise in the cold while
hypohydrated does not alter metabolic heat production, skin temperatures and
heat loss, nor does it increase thermoregulatory and cardiovascular strain.
PMID: 15045503 [PubMed]
22: Endocrinology. 2004 Mar 24 [Epub ahead of print]
CPT-1 Activity Stimulation by Cerulenin via SNS Activation Overrides Cerulenin's
Peripheral Effect.
Jin YJ, Li SZ, Zhao ZS, An JJ, Kim RY, Kim YM, Baik JH, Lim SK.
Division of Endocrinology, Department of Internal Medicine, College of Medicine,
Yonsei University, Seoul, Korea.; School of Life Sciences and Biotechnology,
Korea University, Seoul, Korea.; Brain Korea 21 Project for Medical Sciences,
Yonsei University, Seoul, Korea.; Division of Endocrinology, Department of
Internal Medicine, Affiliated Hospital, Medical College, YanBian University,
YanJi, People's Republic of China.
To clarify the paradoxic effects of cerulenin, namely, its in vitro inhibitory
effects on fat catabolism, and its in vivo reduction of fat mass, we studied the
in vivo and in vitro effects of cerulenin on carnitine palmitoyltransferase-1
(CPT-1) activity, the rate-limiting enzyme of fatty acid oxidation. A single
intraperitoneal (IP) injection of cerulenin significantly reduced body weight
and increased core temperature without significantly reducing food intake. In
situ hybridization study revealed that a single injection of cerulenin did not
affect the expression of orexigenic neuropeptide mRNA. Cerulenin's effect on
CPT-1 activity was biphasic in the liver and muscle: early suppression during
the first 1 h and late stimulation in the 3 approximately 5 h following IP
treatment. In vitro cerulenin treatment reduced CPT-1 activity, which was
overcome by co-treating with catecholamine. Intracerebroventricular injection of
cerulenin increased CPT-1 activity significantly in soleus muscle and this
effect was sustained for up to 3 h. Pretreatment with alpha-methyl-p-tyrosine
inhibited the cerulenin-induced increase in core temperature and the late phase
stimulating effect of cerulenin on CPT-1 activity. In adrenalectomized mice,
cerulenin also increased the activity. In vivo cerulenin treatment enhanced
muscle CPT-1 activity in monosodium glutamate-treated arcuate nucleus lesioned
mice, but not in gold thioglucose-treated ventromedial hypothalamus lesioned
mice. These findings suggest that cerulenin-induced late phase stimulating
effects on CPT-1 activity and energy expenditure is mediated by the activation
of innervated sympathetic nervous system neurons through the firing of undefined
neurons of the ventromedial hypothalamus, rather than the arcuate nucleus.
PMID: 15044358 [PubMed]
23: Scand J Med Sci Sports. 2004 Apr;14(2):74-99.
Fat metabolism in exercise--with special reference to training and growth
hormone administration.
Lange KH.
Sports Medicine Research Unit, Bispebjerg Hospital, Copenhagen, Denmark.
klange@dadlnet.dk
Despite abundance of fat, exclusive dependency on fat oxidation can only sustain
a metabolic rate corresponding to 50-60% of VO(2max) in humans. This puzzling
finding has been subject to intense research for many years. Lately, it has
gained renewed interest as a consequence of increased obesity and physical
inactivity imposed by Western lifestyle. Why are humans so poor at metabolizing
fat? Can fat metabolism be manipulated by exercise, training, diet and hormones?
And why is fat stored in specialized adipose tissue and not just as lipid
droplets inside muscle cells? In the present review, human fat metabolism is
discussed in relation to how human fat metabolism is designed. Limitations in
this design are explored and examples of different designs for fat metabolism
from animal physiology are included to illustrate these limitations. Various
means of manipulating fat metabolism are discussed with special emphasis on
exercise, training, growth hormone (GH) physiology and GH administration. It is
concluded that fat stores, non-esterified fatty acids (NEFAs) availability and
enzymes for fat oxidation can be increased substantially. However, it is almost
impossible to increase fat oxidation during endurance exercise at higher
intensities. It seems that, for some reason, the human being is far from
optimally designed for fat oxidation during exercise. Acute GH administration
has several unexpected effects on fat and carbohydrate metabolism during aerobic
exercise, and future research in this area is likely to provide valuable
information with respect to GH physiology and the regulation of fat and
carbohydrate metabolism during aerobic exercise.
PMID: 15043630 [PubMed]
24: Br J Sports Med. 2004 Apr;38(2):186-90.
Effects of exercise on the physical condition of college rugby players during
summer training camp.
Mashiko T, Umeda T, Nakaji S, Sugawara K.
Department of Health and Physical Education, National Defense Medical College,
Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan.
OBJECTIVES: To determine the effects of exercise training on physical condition
in 25 college rugby players during a summer training camp, and to compare these
variables by the different players' positions. METHODS: Changes in body
composition parameters and blood biochemistry were examined before and after a
summer training camp. RESULTS: Body weight and percentage body fat did not
change significantly during the camp. There were significant decreases in levels
of serum total cholesterol, triglycerides, phosphate, uric acid, and
immunoglobulin G and M. In contrast, there were significant increases in levels
of serum potassium, markers of renal, hepatic, and muscular damage (BUN, GOT,
GPT, LDH, CK), and complement C4. Comparison of the changes in biochemical
parameters between rugby players playing in different positions showed a
significant increase in serum albumin level in the forwards, and significant
decreases in serum triglyceride and sodium levels in the backs. The magnitude of
change in serum LDH during the camp was significantly greater (p<0.05) for the
forwards than for the backs. CONCLUSIONS: These data suggest that, in rugby
players attending a 20 day camp, exercise training resulted in muscular damage,
loss of electrolytes due to sweating, and changes in immune function. Backs
exhibited a higher rate of fat metabolism and loss of electrolytes than
forwards, possibly because they did more running during the camp. In contrast,
forwards experienced more physical contact, performed more physically strenuous
exercise, and exhibited higher levels of muscular damage and tissue protein
degradation.
PMID: 15039257 [PubMed]
25: Int J Obes Relat Metab Disord. 2004 Mar 23 [Epub ahead of print]
Relationship between changes in food group variety, dietary intake, and weight
during obesity treatment.
Raynor HA, Jeffery RW, Tate DF, Wing RR.
1Department of Psychiatry and Human Behavior, Brown University, The Miriam
Hospital, Providence, RI, USA.
BACKGROUND:: Experimental studies show diets with greater variety in
energy-dense foods increase consumption and body weight. Reducing variety in
energy-dense food groups may decrease energy and dietary fat intake, promoting
weight loss. OBJECTIVE:: This study examined changes in food group variety
during obesity treatment and the relation between changes in food group variety,
dietary intake, and weight. DESIGN:: Overweight men and women (n=202) were
randomly assigned to one of two standard behavioral treatments with varying
exercise prescriptions (exercise level of 4186 kJ/week (1000 kcal/week) or 10465
kJ/week (2500 kcal/week)), but received the same diet. Complete measures were
obtained from 122 participants, of which 70 (58%) were female, with a mean body
mass index of 31.3 kg/m(2) (s.d.=2.5). MEASUREMENTS:: Food group variety and
diet composition were assessed at 0, 6, and 18 months from food-frequency
questionnaires. Food group variety was calculated as percent of foods consumed
on a weekly basis within a food group, irrespective of servings consumed.
RESULTS:: Participants reported increased variety (P 0.10) affect Warner-Bratzler shear force (WBSF), collagen
amount (OH-PRO) or cross-linking (HP), temperature, or pH. Steaks from WxL aged
14 d postmortem had lower (P < 0.05) WBSF values than L (W were intermediate).
Cooking time was longer (P < 0.01) in W and WxL than in L; however, breed did
not affect (P > 0.10) cooking loss. Cooking time was not influenced by diet, but
steaks from cattle fed 6% sunflower oil had lower (P < 0.05) cooking losses.
Temperature decreased more (P < 0.05) rapidly, and pH more slowly (P < 0.05), in
W and WxL than L in the first 24 h postmortem. Limousin steaks were lighter
(higher L*) and more yellow (higher b*) in color than steaks from W and WxL (P <
0.05). The control diet (no oil added) resulted in steaks that were lighter (P <
0.05) than the treatment diet (6% added sunflower oil). Neither breed nor diet
affected (P > 0.10) OH-PRO or HP concentration. The results of this study
indicate that biological type differences may not be as great in the ST as in
longissimus muscle; thus, to increase tenderness in ST, emphasis may need to be
placed on processing and cooking techniques rather than genetic selection.
PMID: 15032434 [PubMed]
29: Circulation. 2004 Mar 30;109(12):1550-7. Epub 2004 Mar 15.
Fatty acid translocase/CD36 deficiency does not energetically or functionally
compromise hearts before or after ischemia.
Kuang M, Febbraio M, Wagg C, Lopaschuk GD, Dyck JR.
Cardiovascular Research Group, Department of Pediatrics, Faculty of Medicine,
University of Alberta, Edmonton, Alberta, Canada.
BACKGROUND: Evidence from humans suggests that fatty acid translocase (FAT)/CD36
deficiency can lead to functionally and/or energetically compromised hearts, but
the data are equivocal, and the subject remains controversial. In this report we
assessed the contribution of FAT/CD36 to overall fatty acid oxidation rates in
the intact heart and determined the effect of FAT/CD36 on energy metabolism
during reperfusion of ischemic hearts. METHODS AND RESULTS: Isolated working
hearts from wild-type and FAT/CD36-knockout (KO) mice were perfused with
Krebs-Henseleit solution containing 0.4 or 1.2 mmol/L [U-3H]palmitate, 5 mmol/L
[U-14C]glucose, 2.5 mmol/L calcium, and 100 microU/mL insulin at a preload
pressure of 11.5 mm Hg and afterload pressure of 50 mm Hg. Hearts were
aerobically perfused for 30 minutes or aerobically perfused for 30 minutes,
followed by 18 minutes of global no-flow ischemia and 40 minutes of aerobic
reperfusion. Rates of fatty acid oxidation in FAT/CD36-KO hearts were
significantly lower than in wild-type hearts at both concentrations of palmitate
(0.4 or 1.2 mmol/L). In addition, hearts from FAT/CD36-KO mice displayed a
compensatory increase in glucose oxidation rates. On aerobic reperfusion after
ischemia, cardiac work of FAT/CD36-KO hearts recovered to the same extent as
wild-type hearts. CONCLUSIONS: FAT/CD36-deficient hearts are not energetically
or functionally compromised and are not more sensitive to ischemic injury
because glucose oxidation can compensate for the loss of fatty acid-derived ATP.
PMID: 15023869 [PubMed]
30: Asia Pac J Clin Nutr. 2003;12 Suppl:S52.
High dairy-protein versus high mixed-protein energy restricted diets - the
effect on bone turnover and calcium excretion in overweight adults.
Bowen J, Noakes M, Clifton P.
Clinical Research Unit, CSIRO Health Sciences and Nutrition, PO Box 10041,
Adelaide, SA 5000.
Background - A moderate exchange of some dietary carbohydrate for protein
appears to have metabolic and weight loss advantages in human studies. This
dietary strategy raises safety concerns for bone health. The impact of dietary
calcium in high protein diets on bone turnover has not been investigated.
Objective - This study examined the effect of protein source and calcium content
in high protein, energy restricted diets on calcium excretion and bone
metabolism in 50 overweight adults (BMI 33.4 +/- 2.1 kg/m(2)). Design - The
parallel study consisted of a 12-week energy restriction phase followed by a
four-week energy balance phase. Subjects were randomised to one of two
isoenergetic (5.5 MJ/d, 34% energy from protein, 41% from carbohydrate and 24%
from fat) diets; high dairy protein (DP, 2400mg Ca/d) or high mixed protein (MP,
500mg Ca/d). Outcomes - Energy restriction was the primary determinant of weight
loss (-9.7 +/- 3.8 kg, P<0.01) with no significant effect of protein source.
Twenty-four hour calcium excretion decreased during both interventions (-1.09
+/- 0.23 mmol/day, P<0.009). By week 16 the MP diet had a 40% larger increase in
deoxypyridinoline (a bone turnover marker) compared to the DP diet (P=0.008).
Osteocalcin (a marker of bone formation) increased from week zero to 16 in the
MP diet only (+2.22 ng/ml P=0.001). Conclusions - Overall, the DP diet has a
modest advantage over MP diet by reducing the accelerated bone turnover
associated with weight loss.
PMID: 15023671 [PubMed]
31: Asia Pac J Clin Nutr. 2003;12 Suppl:S10.
Dietary approaches for weight loss with increased fruit, vegetables and dairy.
Booth AO, Nowsen CA, Worsley T, Margerison C, Jorna MK.
School of Health Sciences, Deakin University, Burwood, VIC 3215.
Objective - To assess the consumption of fruit, vegetables and non-fat dairy
products of subjects in a weight loss study where strategies were used to
increase intakes. Design - Subjects were randomised to one of two diet and
exercise weight loss programs for 12 weeks (n=40). The WELL diet (a Dietary
Approaches to Stop Hypertension (DASH) type diet with a weight loss focus)
included daily targets of four serves of fruits, four serves of vegetables and
three serves of no fat dairy. The National Heart Foundation's (NHF) 'Healthy
Weight Guide' diet included general advice to increase fruit and vegetable
consumption but no specific targets. Subjects were visited or phoned
fortnightly. They received group weight loss feedback as well as a personalized
program that included lifestyle advice, feedback and goal setting. A food group
counter recorded servings of fruit, vegetables and dairy products on three
consecutive days of each week. Results of the first eight weeks are reported.
Results - At week 8, number of serves/day of targeted foods were greater for the
WELL diet than the NHF diet (mean difference+/-SEM): Fruit: 1.5+/-0.3,
vegetables: 1.5+/-0.2, dairy: 1.3+/-0.1 serves/day (all P<0.01). Vegetables
serves/day (mean+/-SEM) on the WELL diet increased from week two to week eight
(week two: 3.3+/-0.2, week eight: 4.1+/-0.4 serves/day (P<0.05)). Daily fruit
intake remained above target (week two: 4.7+/-0.2, week eight: 4.8+/-0.1
serves/day). Daily dairy intake remained below target (week two: 2.7+/-0.2, week
eight: 2.8 +/-0.2serves/day). Conclusions - Changing dietary patterns may
require different adjustment periods depending on the food type. Increasing
fruit intake can be implemented quickly, whereas it takes a longer time to
increase vegetable intake. Providing specific dietary targets appears to promote
greater adherence to guidelines than general advice to increase intakes alone.
PMID: 15023596 [PubMed]
32: Asia Pac J Clin Nutr. 2003;12 Suppl:S9.
The effect of protein source (dairy vs mixed) in high protein, energy restricted
diets on body composition, vascular health and metabolic markers in overweight
adults.
Bowen J, Noakes M, Clifton P.
Clinical Research Unit, CSIRO Health Sciences and Nutrition, PO Box 10041,
Adelaide, SA.
Background - An increase in the protein/carbohydrate ratio in low calorie diets
has been linked with improved metabolic profile. It is unclear if the source of
dietary protein exerts any affects. There is limited evidence that high calcium
diets may facilitate body fat loss. Objective - This study examined whether a
high dairy protein/calcium diet versus a mixed protein/low calcium diet affected
weight loss and cardiovascular and liver function markers. Design - The parallel
study consisted of a 12-week phase energy restriction followed by a 4-week
energy balance phase. Fifty adults (BMI 33.4 +/- 2.1 kg/m(2)) followed
isocaloric diets (5.5MJ/day, 34% protein, 41% carbohydrate, 24% fat) high in
dairy (DP, 2400mg Ca/d) or mixed protein (MP, 500mg Ca/d). Body composition,
glycemic control, serum lipids, blood pressure and markers of vascular and liver
function were measured throughout the study. Outcomes - There was no effect of
protein source on net weight loss or body composition (-9.7 +/- 3.8kg, P=0.8).
Prior to weight loss, glycemic response to DP or MP test meals was 30% lower in
subjects on the DP diet. Fasting total and LDL-cholesterol, triglycerides,
insulin and blood pressure decreased after weight
loss(-0.41+/-0.07mmol/L,-0.36+/-0.1mmol/L,-0.23+/-0.06 mmol/L,-1.4+/-0.6mU/L,
-9.4/-2.5mmHg P<0.01, respectively) independent of protein source. There was an
improvement in some markers of liver function as well as markers of vascular
function (GTT, AST, PAI, sICAM, tPA) with weight loss (-20.1+/-4.1%,-11.2+/-17%,
-15.2+/-7.3%,-6.9+/-2.2%,+25.9+/-6.2%, respectively P<0.01). Conclusions - Both
diets resulted in improvements in cardiovascular risk markers and liver
function. Neither protein source nor dietary calcium significantly affected
weight loss or body composition. The DP test meal resulted in a slightly more
favourable glucose response.
PMID: 15023595 [PubMed]
33: Asia Pac J Clin Nutr. 2003;12 Suppl:S8.
Novel treatments for Obesity.
Ludwig DS.
Department of Medicine, Children's Hospital Boston, MA, USA.
Background - Excessive fat consumption is commonly believed to cause obesity
and, for this reason, conventional approaches to weight loss have focused on
decreasing dietary fat. However, the relationship between dietary fat and
adiposity has been questioned for several reasons: 1) weight loss on low-fat
diets is characteristically modest in nature; 2) prospective epidemiological
studies have not consistently found that individuals eating the most fat are
heavier than those eating the least fat; and 3) obesity prevalence has risen
markedly since the 1970s in the US despite a significant decrease in fat
consumption as a percent of total energy. As dietary fat has decreased,
carbohydrate consumption has increased in a compensatory fashion, and most of
this increase has been in the form of refined starchy food and concentrated
sugar that are high in glycemic index (GI) and/or glycemic load (GL). Review -
Physiological studies demonstrate that consumption of high GI/GL meals induce a
sequence of hormonal changes that limit availability of metabolic fuels in the
post-prandial period and cause overeating. Short-term feeding studies
consistently show less satiety or greater voluntary energy intake after
consumption of high compared to low GI meals. Several intermediate-term clinical
trials found greater weight loss among overweight individuals on low compared to
low GI diets. A recent study from our group found significantly greater weight
and fat mass decrease among obese adolescents consuming a reduced GL compared to
a reduced fat diet for 12 months. Animal studies support a role for GI in body
weight regulation. Moreover, GI and GL appear to affect risk for diabetes and
heart disease after controlling for body weight. Conclusions - Reduction in
GI/GL comprises a novel and exciting approach to the prevention and treatment of
obesity and related complications. A low GI/GL diet may be an ideal compromise
between low fat diets at one end of the spectrum, and very low carbohydrate
diets at the other. Long-term, large-scale studies of such diets should assume a
high public health priority.
PMID: 15023593 [PubMed]
34: Asia Pac J Clin Nutr. 2003;12 Suppl:S4.
Diet and development of the insulin resistance syndrome.
Ludwig DS.
Department of Medicine, Children's Hospital Boston, MA,SA.
Background -Insulin influences a large number of physiological functions in a
variety of organs and tissues. From a broad perspective, insulin resistance
provides the body with the ability to regulate the actions of this potent
anabolic hormone in a highly discrete fashion. Many patho-physiological factors
can alter the functions of insulin at one or more sites, potentially conferring
biological benefit. However, insulin resistance and compensatory
hyperinsulinemia in the setting of central adiposity adversely affects important
diabetes and cardiovascular disease risk factors - namely glucose tolerance,
blood pressure, serum lipids, coagulation tendency, chronic inflammation and
perhaps oxidative stress - that together comprise the insulin resistance
syndrome (IRS). Review - Dietary factors have increasingly been recognized as
important determinants of insulin resistance and, by implication, development of
the IRS. Though low fat/high carbohydrate diets have been traditionally
recommended to reduce risk for diabetes and cardiovascular disease, recent
research has suggested that such diets may actually increase risk for IRS among
susceptible individuals. On balance, macronutrient quantity may be less
important in this regard than nutrient quality. Whereas saturated and
trans-fatty acids increase insulin resistance, mono and poly-unsaturated fats
decrease resistance and offer protection against disease. Similarly, some types
of carbohydrate (refined starch, concentrated sugar) promote, and other types
(high fiber, low glycemic index) protect against IRS. Beyond macronutrients,
specific food groups have become the subject of increasing interest.
Observational and interventional studies suggest that dairy products, including
full fat versions, lower risk for IRS, an effect that might be mediated by
intrinsic compounds in dairy (e.g calcium) or by displacement of less healthful
foods (e.g soft drinks) from the diet. Preliminary studies suggest that certain
micronutrients might also influence risk. Conclusions - Among modifiable factors
including weight loss and exercise, dietary composition appears to have an
important effect on development of IRS. The available evidence suggests that
IRS, and therefore diabetes and cardiovascular disease, can be prevented by a
high fiber/low glycemic index diet containing dairy products and a higher amount
of unsaturated fats than currently recommended.
PMID: 15023589 [PubMed]
35: Fertil Steril. 2004 Mar;81 Suppl 1:792-7.
Oxidative stress indices in seminal plasma, as measured by the
thermochemiluminescence assay, correlate with sperm parameters.
Lissak A, Wiener-Megnazi Z, Reznick AZ, Shnizer S, Ishai D, Grach B,
Lahav-Baratz S, Shiloh H, Koifman M, Dirnfeld M.
IVF Unit, Department of Obstetrics and Gynecology, Carmel Medical Center, 7
Michal Street, Haifa, Israel.
OBJECTIVE: To examine the effect of oxidation of proteins and lipids, as
measured by a novel thermochemiluminescence (TCL) analyzer, and to evaluate the
correlation between TCL indices in seminal plasma and sperm parameters. DESIGN:
Experimental and prospective clinical studies. SETTING: An infertility unit.
PATIENT(S): One hundred forty-eight men undergoing semen analysis.
INTERVENTION(S): Bovine serum albumin (BSA) and linolenic acid were oxidized and
tested by TCL, protein carbonyls, and conjugated dienes assays. All participants
underwent semen analysis. Seminal plasma was tested by TCL and conjugated
dienes. MAIN OUTCOME MEASURE(S): Thermochemiluminescence indices before and
after oxidation of BSA and linolenic acid, compared with protein carbonyl and
conjugated dienes indices. Correlation between semen parameters and TCL and
conjugated dienes indices in seminal plasma. RESULT(S): Oxidation of BSA and
linolenic acid was marked by characteristic changes in their TCL curve pattern
and an increase in the levels of protein carbonyls and conjugated dienes. Among
125 sperm-containing semen samples, the TCL curve exhibited two patterns: a
positive relative ratio curve (group A, 87 patients) and a negative relative
ratio curve (group B, 38 patients). Sperm concentration was lower and total
motile sperm and rapid motile sperm were fewer in group B. A significant
correlation was found between TCL indices, conjugated dienes, and sperm quality
in group B. CONCLUSION(S): Oxidation affects TCL curve pattern of proteins and
lipids in a characteristic manner. Thermochemiluminescence indices in seminal
plasma closely correlate with sperm characteristics among patients with sperm
disturbances, and it might serve as a tool in the evaluation, treatment, and
monitoring of subfertile men.
PMID: 15019811 [PubMed]
36: Pediatr Diabetes. 2000 Mar;1(1):23-33.
Recent advances in the treatment of childhood obesity.
Suskind R, Blecker U, Udall Jr J, Von Almen T, Schumacher H, Carlisle L, Sothern
M.
The Chicago Medical School, North Chicago, IL, USA.
The rapid increase in the prevalence of obesity in the last decade indicates a
need for effective treatment programs. We conducted a short-term,
repeated-measures, clinical-outcome trial in three groups of children and
adolescents in two different locations. Two cohorts (n=34) were enrolled in a
36-wk multi-disciplinary weight-management program at the Children's Hospital of
New Orleans. One cohort (n=16) was enrolled in a similar intervention at the
General Clinical Research Center (GCRC) at the Medical Center of Louisiana for a
10-wk summer weight-loss program. Subjects were offered a protein-sparing
modified fast (PSMF) diet (600-800 kcal/d; 2 g protein/kg body weight), followed
by a balanced hypocaloric diet, and they participated in behavior-modification
sessions and a moderate-intensity (45-55% volume of oxygen consumed at maximal
effort [VO(2)max]), progressive exercise program. The following parameters were
examined at baseline, 10 wk, and 36 wk (cohort 1 only): Weight, height,
percentage of ideal body weight (%IBW), relative body fat (%fat), fat free body
(FFB) mass, estimated VO(2)max mL/kg min(BW) [adjusted for body weight]), blood
chemistries, lipid profiles (total cholesterol [TC], triglycerides [TG],
low-density lipoprotein [LDL], high-density lipoprotein [HDL], and insulin-like
growth factor-1 [IGF-1]). All three groups experienced significant decreases in
weight, %IBW and %fat at 10 wk. The weight loss was maintained at 26 wk in
cohorts 1 and 2, and at 36 wk in cohort 1. There were no significant decreases
in height velocity during the study. In addition, measures of estimated VO(2)max
mL/kg/min(BW) and IGF-1 parameters were significantly greater at 10 wk compared
to baseline. Measures of TC, TG, and LDL were significantly lower at 10 wk, with
no significant changes noted in HDL. We conclude that a multi-disciplinary
weight-management program, including PSMF, behavior modification, and exercise,
provides an effective method of treatment for obesity in children and
adolescents. Long-term, randomized, and controlled clinical trials are needed to
confirm the results of this preliminary, short-term observation.
PMID: 15016239 [PubMed]
37: Pediatr Diabetes. 2000 Jun;1(2):61-5.
Changes in body composition after a 12-wk aerobic exercise program in obese
boys.
DeStefano RA, Caprio S, Fahey JT, Tamborlane WV, Goldberg B.
Section of Cardiology, Department of Pediatrics and the Children's Clinical
Research Center, Yale University School of Medicine, New Haven, CT 06520, USA.
Previous studies have shown that vigorous aerobic training programs for obese
children result in minimal weight changes, and concluded that they may not be
beneficial. Weight change alone may not detect important beneficial changes in
body composition associated with vigorous training in these children. Fifteen
obese boys (aged 9-12 yr, body mass index (BMI) 31.8+/-6.5, average percent body
fat (%BF) 41+/-4.2) underwent a supervised aerobic and resistance training
program (12 wk, 2 days/wk for 30 min/session), to investigate the effects on
weight and body composition. After the 3-month training period, weight loss
averaged only 1.5+/-1.0 kg (not significant), but total body fat decreased by
4.1+/-1.8 kg (p<0.05) and fat-free mass (FFM) increased by 2.6+/-1.1 kg (p<0.05)
based on hydrostatic weighing. As a result, %BF fell by 10% (p<0.01). There was
a 5.8+/-2.8 mL/kg/min (p<0.05) increase in peak volume of oxygen uptake (VO(2)),
along with a 248+/-120 kcal/d (p<0.05) increase in resting energy expenditure
(REE). Activity questionnaires showed a significant increase in high intensity
recreational activities (6.5+/-1.5 vs 3.5+/-0.5 h physical activity/wk; p<0.01)
in the home and a significant decrease in low intensity activities (7+/-2.0 vs
12+/-3.5 h TV viewing/wk; p<0.01). Conclusions: Vigorous supervised aerobic
training in obese boys has beneficial effects on body composition, fitness and
leisure time activities that are not apparent by measurement of changes in body
weight alone.
PMID: 15016230 [PubMed]
38: Metabolism. 2004 Mar;53(3):388-96.
The hyperinsulinemic amino acid clamp increases whole-body protein synthesis in
young subjects.
Chevalier S, Gougeon R, Kreisman SH, Cassis C, Morais JA.
McGill Nutrition and Food Science Centre, Montreal, Quebec, Canada.
We propose that hyperinsulinemia stimulates protein synthesis when
postabsorptive plasma amino acid (AA) concentrations are maintained. During a
euglycemic hyperinsulinemic clamp, many AA, notably the branched-chain amino
acids (BCAA), decline markedly. Therefore, we tested whether individual plasma
AA could be maintained within the range of postabsorptive concentrations to
assess the effects of insulin, infused at 40 mU/m(2) x min on whole-body protein
and glucose metabolism, using [1-(13)C]-leucine and [3-(3)H]-glucose
methodology. Validation studies of background [(13)C] enrichment and breath
(13)CO(2) recovery factors were performed in a subset of 6 subjects. In 10
healthy, young men, infusion rates of an AA solution were based on fluorometric
determinations of total BCAA every 5 minutes. All 21 plasma AA remained in the
target range; 15, including the BCAA, alanine, and glycine were within 13% of
baseline, and only 6 (Thr, His, Arg, Asn, Cit, Tyr) varied more (18% to 42%).
Notably, both leucine flux and nonoxidative leucine R(d) (protein synthesis)
increased with insulin (2.36 +/- 0.06 to 2.81 +/- 0.10 and 1.79 +/- 0.05 to 2.18
+/- 0.10 micromol/kg fat-free mass (FFM) x min, respectively; P <.0005) while
leucine oxidation only tended to increase (P =.05) and endogenous leucine R(a)
(protein breakdown) decreased by 18% (2.36 +/- 0.06 to 1.94 +/- 0.09 micromol/kg
FFM x min; P <.0005), resulting in a marked elevation of net protein synthesis
(-0.57 +/- 0.02 to 0.24 +/- 0.02 micromol/kg FFM x min; P <.0000001). Thus, in
vivo protein anabolism was induced when maintaining postabsorptive plasma amino
acid concentrations during hyperinsulinemia through a suppression of whole-body
protein breakdown, no significant change in oxidation and an elevation of
synthesis compared with postabsorptive conditions.
PMID: 15015153 [PubMed]
39: MMW Fortschr Med. 2003 Apr 28;145 Spec No 1:28-32.
[In Process Citation]
[Article in German]
Weber K, Heiken H, Stoll M, Schmidt RE, Behrens G.
Abteilung Klinische Immunologie, Medizinische Hochschule Hannover.
weber-r.klaus@mh-hannover.de
A common problem seen with the long-term use of highly active antiretroviral
therapy (HAART) is the HIV-associated lipodystrophy syndrome. Clinical signs
include a loss of peripheral subcutaneous fatty tissue, an increase in visceral
or local fat, and altered glucose and lipid metabolism. The physical changes
frequently impair quality of life, and the patient's adherence to treatment
regimens. Metabolic changes may possibly represent cardiovascular risks with
incalculable consequences over the long term. Although the lipodystrophy
syndrome was first described in 1998. It still lacks a definition. So far,
therapeutic strategies have remained ineffective or have had only limited
success. Proposed treatments include general recommendations (diet, physical
exercise, etc.), changing the antiretroviral therapy, and treatment with
metabolically active medication.
PMID: 15011581 [PubMed]
40: Br J Plast Surg. 2004 Apr;57(3):190-4.
Comment in:
Br J Plast Surg. 2004 Apr;57(3):189.
Effect of liposuction on insulin resistance and vascular inflammatory markers in
obese women.
Giugliano G, Nicoletti G, Grella E, Giugliano F, Esposito K, Scuderi N, D'Andrea
F.
Chair of Plastic and Reconstructive Surgery, Second University of Naples,
Naples, Italy. dario.giugliano@unina2.it
Liposuction is one of the more common elective surgical procedures in the US and
is supposed to be on the increase. There are no reported studies specifically
addressing the metabolic sequelae of liposuction in obesity. The aim of the
present study was to investigate the role of large-volume liposuction on insulin
resistance and circulating inflammatory markers in obese people. Thirty healthy
premenopausal obese (body mass index (BMI) from 30 to 45) and 30 age-matched
normal weight (BMI<25) women were studied. In obese women, insulin sensitivity,
as measured by the Homeostasis Model Assessment (HOMA=fasting plasma glucose x
fasting serum insulin divided by 25), as well as serum adiponectin, the novel
adipocytokine with insulin sensitising properties, were significantly lower, as
compared with nonobese women (p<0.01), indicating insulin resistance; on the
contrary, serum concentrations of the proinflammatory cytokines IL-6, IL-18 and
TNF-alpha, as well as the sensitive marker of inflammation C-reactive protein,
were significantly higher (p<0.01). All obese women were submitted to a single
large volume liposuction (superwet technique): the mean aspirate volume was 3540
ml (range 2550-4670), corresponding to a net lipid loss of 2.7+/-0.7 kg
(mean+/-SD). After six months of stable body weight after liposuction, women
were less insulin resistant (p<0.05), had reduced concentrations of IL-6, IL-18,
TNF-alpha and CRP (p<0.05-0.02), and increased serum levels of adiponectin
(p<0.02) and HDL-cholesterol (p<0.05). There was a significant correlation
between the amount of fat aspirate and changes in HOMA (r=0.28, p<0.05),
TNF-alpha (r=0.31, p<0.02), and adiponectin (r=-0.34, p<0.02), as well as
between the decrease in TNF-alpha and the increase in adiponectin after the
surgical procedure (r=-0.45, p<0.01). Our study demonstrates that liposuction is
safe and free of metabolic sequelae in obese women, pending a careful screening
of the patient. Moreover, it is associated with amelioration of insulin
resistance and reduced circulating markers of vascular inflammation which may
help obese subjects to reduce their cardiovascular risk.
PMID: 15006519 [PubMed]
41: Am J Physiol Regul Integr Comp Physiol. 2004 Apr;286(4):R734-9.
Leptin prevents obesity induced by a high-fat diet after diet-induced weight
loss in the marsupial S. crassicaudata.
Wittert GA, Turnbull H, Hope P, Morley JE, Horowitz M.
Department of Medicine, Royal Adelaide Hospital, Adelaide SA 5000, Australia.
gary.wittert@adelaide.edu.au
The aims of this study were to determine in the marsupial Sminthopsis
crassicaudata, the effects of leptin on food intake, body weight, tail width (a
reflection of fat stores), and leptin mRNA, after caloric restriction followed
by refeeding ad libitum with either a standard or high-fat preferred diet. S.
crassicaudata (n = 32), were fed standard laboratory diet (LabD; 1.01 kcal/g,
20% fat) ad libitum fo 3 days. On days 4-10, animals received LabD at 75% of
basal intake and then (days 11-25) were fed either LabD or a choice of LabD and
mealworms (MW; 2.99 kcal/g, 30% fat); during this time, half the animals (n = 8)
in each group received either leptin (2.5 mg/kg) or PBS intraperitoneally two
times daily. On day 26, animals were killed and fat was removed for assay of
leptin mRNA. At baseline, body weight, tail width, and food intake were similar
in each group. After caloric restriction, body weight (P < 0.001) and tail width
(P < 0.001) decreased. On return to ad libitum feeding in the PBS-treated
animals, body weight and tail width returned to baseline in the LabD-fed animals
(P < 0.001) and increased above baseline in the MW-fed animals (P < 0.001). In
the LabD groups, tail width (P < 0.001) and body weight (P < 0.001) decreased
after leptin compared with PBS. In the MW groups, the increase in tail width (P
< 0.001) and body weight (P = 0.001) were attenuated after leptin compared with
PBS. The expression of leptin mRNA in groups fed MW were greater in PBS than in
leptin-treated animals (P < 0.05). Therefore, after diet-induced weight loss,
leptin prevents a gain in fat mass in S. crassicaudata; this has potential
implications for the therapeutic use of leptin.
PMID: 15003944 [PubMed]
42: J Clin Endocrinol Metab. 2004 Mar;89(3):1301-11.
Dissociation between fat-induced in vivo insulin resistance and proximal insulin
signaling in skeletal muscle in men at risk for type 2 diabetes.
Storgaard H, Jensen CB, Bjornholm M, Song XM, Madsbad S, Zierath JR, Vaag AA.
Department of Endocrinology and Clinical Research Unit, Hvidovre Hospital,
University of Copenhagen, DK-2650 Hvidovre, Denmark. hstorgaard@dadlnet.dk
The effect of short- (2 h) and long-term (24 h) low-grade Intralipid infusion on
whole-body insulin action, cellular glucose metabolism, and proximal components
of the insulin signal transduction cascade was studied in seven obese male
glucose intolerant first degree relatives of type 2 diabetic patients [impaired
glucose tolerance (IGT) relatives] and eight matched control subjects. Indirect
calorimetry and excision of vastus lateralis skeletal muscle biopsies were
performed before and during hyperinsulinemic euglycemic clamps combined with
3[(3)H]glucose. Clamps were performed after 0, 2, or 24 h Intralipid infusion
(0.4 ml.kg(-1).min(-1)). Insulin-stimulated glucose disposal decreased
approximately 25% after short- and long-term fat infusion in both IGT relatives
and controls. Glucose oxidation decreased and lipid oxidation increased after
both short- and long-term fat infusion in both groups. Insulin-stimulated
glucose oxidation was higher after long-term as compared with short-term fat
infusion in control subjects. Short- or long-term infusion did not affect the
absolute values of basal or insulin-stimulated insulin receptor substrate-1
tyrosine phosphorylation, tyrosine-associated phosphoinositide 3-kinase (PI
3-kinase) activity, insulin receptor substrate-1-associated PI 3-kinase
activity, or Akt serine phosphorylation in IGT relatives or matched controls. In
fact, a paradoxical increase in both basal and insulin-stimulated PI 3-kinase
activity was noted in the total study population after both short- and long-term
fat infusion. Short- and long-term low-grade Intralipid infusion-induced (or
enhanced) whole-body insulin resistance and impaired glucose metabolism in IGT
relatives and matched control subjects. The fat-induced metabolic changes were
not explained by impairment of the proximal insulin signaling transduction in
skeletal muscle.
Publication Types:
Clinical Trial
PMID: 15001626 [PubMed]
43: Eur J Nutr. 2004 Feb;43(1):2-6. Epub 2004 Jan 06.
Plasma antioxidants and lipid oxidation after submaximal resistance exercise in
men.
Ramel A, Wagner KH, Elmadfa I.
Unit for Nutrition Research, University of Iceland, Eiriksgata 29, 101,
Reykjavik, Iceland. ramel@hi.is
BACKGROUND: An increased generation of reactive oxygen species occurs during
exercise. THE AIM OF THE STUDY: We investigated whether changes in plasma
antioxidants and lipid oxidation products after submaximal resistance exercise
are detectable, and whether training status has any effect on changes. METHODS:
Seven resistance trained (RT, 31.3 +/- 10.2 yrs) and ten non-resistance trained
male subjects (NRT, 28.2 +/- 3.9 yrs) performed a submaximal resistance exercise
circuit (10 different exercises, 75% of 1-repetition maximum, 18.6 +/- 1.1
minutes). Blood samples were taken before and immediately after exercise. Plasma
antioxidants (AO), lipid oxidation products malondialdehyde (MDA) and conjugated
dienes (CD) were measured using HPLC and/or photometric detection. Groups were
compared using the Mann-Whitney U test, the exercise effect was tested using the
Wilcoxon signed ranks test. P < 0.05 was regarded as significant. RESULTS:
alpha-Tocopherol, gamma-tocopherol, beta-carotene, lycopene, ascorbic acid,MDA
and CD concentrations did not differ between groups at rest. There was a similar
increase of fat soluble plasma AO in both groups after exercise, but not
ascorbic acid. MDA increased also in both groups after exercise, but CD
increased only in NRT. CONCLUSION: There is no difference in plasma AO and lipid
oxidation products in RT and NRT at rest. After short time resistance exercise
there is a mobilization of fat soluble AO. Despite mobilization of AO, oxidative
stress occurs during submaximal resistance exercise, which is indicated by
increased MDA and CD concentrations. As exercise induced an increase of CD only
in NRT, it seems that regular resistance training partly prevents lipid
peroxidation during exercise.
PMID: 14991263 [PubMed]
44: J Nutr. 2004 Mar;134(3):586-91.
High-protein, low-fat diets are effective for weight loss and favorably alter
biomarkers in healthy adults.
Johnston CS, Tjonn SL, Swan PD.
Department of Nutrition, Arizona State University, Mesa, AZ 85212, USA.
carol.johnston@asu.edu
Although popular and effective for weight loss, low-carbohydrate, high-protein,
high-fat (Atkins) diets have been associated with adverse changes in blood and
renal biomarkers. High-protein diets low in fat may represent an equally
appealing diet plan but promote a more healthful weight loss. Healthy adults (n
= 20) were randomly assigned to 1 of 2 low-fat (<30% energy), energy-restricted
groups: high-protein (30% energy) or high-carbohydrate (60% energy); 24-h
intakes were strictly controlled during the 6-wk trial. One subject from each
group did not complete the trial due to out-of-state travel; two subjects in the
high-carbohydrate group withdrew from the trial due to extreme hunger. Body
composition and metabolic indices were assessed pre- and post-trial. Both diets
were equally effective at reducing body weight (-6%, P < 0.05) and fat mass (-9
to -11%, P < 0.05); however, subjects consuming the high-protein diet reported
more satisfaction and less hunger in mo 1 of the trial. Both diets significantly
lowered total cholesterol (-10 to -12%), insulin (-25%), and uric acid (-22 to
-30%) concentrations in blood from fasting subjects. Urinary calcium excretion
increased 42% in subjects consuming the high-protein diet, mirroring the 50%
increase in dietary calcium with consumption of this diet; thus, apparent
calcium balance was not adversely affected. Creatinine clearance was not altered
by diet treatments, and nitrogen balance was more positive in subjects consuming
the high-protein diet vs. the high-carbohydrate diet (3.9 +/- 1.4 and 0.7 +/-
1.7 g N/d, respectively, P < 0.05). Thus, low-fat, energy-restricted diets of
varying protein content (15 or 30% energy) promoted healthful weight loss, but
diet satisfaction was greater in those consuming the high-protein diet.
PMID: 14988451 [PubMed]
45: J Nutr. 2004 Mar;134(3):568-73.
A high dairy protein, high-calcium diet minimizes bone turnover in overweight
adults during weight loss.
Bowen J, Noakes M, Clifton PM.
CSIRO Health Sciences and Nutrition, Adelaide, South Australia, Australia, 5000.
Weight loss induces bone resorption and this can be attenuated by calcium
supplementation. Protein-rich diets were recently associated with favorable
effects on bone density, although this remains controversial. We hypothesized
that a diet high in calcium and protein would minimize bone resorption during
weight loss compared with a lower calcium, protein-rich diet. The effects of
dietary calcium in high protein diets on calcium excretion and bone metabolism
were examined in overweight adults (n = 50, BMI 33.4 +/- 2.1 kg/m(2)) during 12
wk of energy restriction followed by 4 wk of energy balance. Subjects were
randomly assigned to isoenergetic diets (5.5 MJ/d, 34% energy from protein, 41%
carbohydrate, 24% fat) high in either dairy protein (DP, 2400 mg Ca/d) or mixed
protein sources (MP, 500 mg Ca/d). During energy restriction, weight loss was
10% (-9.7 +/- 3.8 kg, P < 0.01), and 24-h urinary calcium excretion decreased
independently of diet (-1.09 +/- 0.23 mmol/d, P < 0.01). By wk 16, the MP diet
group had a 40% greater increase in deoxypyridinoline (bone resorption marker)
than the DP diet group (P = 0.008). Osteocalcin (bone formation marker)
increased from wk 0 to 16 in only the MP diet group [+2.16 +/- 0.63 micro g/L
(+0.63 +/- 0.11nmol/L), P = 0.001]. In conclusion, weight loss was associated
with increased bone resorption, yet the DP diet had a modest advantage over the
MP diet by minimizing overall turnover. Combined with reduced urinary calcium
excretion, this suggests that a high-protein, calcium-replete diet may protect
against bone loss during weight reduction.
Publication Types:
Clinical Trial
Randomized Controlled Trial
PMID: 14988448 [PubMed]
46: Am J Clin Nutr. 2004 Mar;79(3):352-61.
Effect of conjugated linoleic acid on body composition and plasma lipids in
humans: an overview of the literature.
Terpstra AH.
Department of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht
University, Utrecht, Netherlands. a.h.m.terpstra@las.vet.uu.nl
Studies in mice have indicated that feeding diets containing 0.5-1% conjugated
linoleic acid (CLA) considerably reduces body fat. These findings have attracted
much interest because of the potential use of CLA as a tool to promote weight
loss in humans. Several CLA studies in humans have now been published, and the
objective of the present review was to give an overview of these experiments.
Most of the studies were done in free-living subjects and were not strictly
controlled for nutrient and energy intakes. None of the studies found a
significant reduction in body weight, and only 2 studies showed a significant
but relatively small body fat-lowering effect. Some studies suggested that CLA
may have a tendency to increase lean body mass. Furthermore, there are
indications from animal studies that CLA may have effects on plasma lipids.
However, only one study in humans showed a significant HDL-cholesterol-lowering
effect of CLA; in all the other studies, there were no significant effects on
plasma total, LDL-, and HDL-cholesterol concentrations or on plasma
triacylglycerol concentrations. Thus, the results of the studies in humans
indicate that the effect of CLA on body fat is considerably less than that
anticipated from mice studies and that CLA has no major effect on plasma lipids.
Publication Types:
Review
Review, Tutorial
PMID: 14985207 [PubMed]
47: Biochim Biophys Acta. 2004 Feb 27;1636(1):59-68.
Induction of lipolysis in vitro and loss of body fat in vivo by
zinc-alpha2-glycoprotein.
Russell ST, Zimmerman TP, Domin BA, Tisdale MJ.
Pharmaceutical Sciences Research Institute, Aston University, Birmingham B4 7ET,
UK.
Loss of adipose tissue in cancer cachexia has been associated with tumour
production of a lipid-mobilizing factor (LMF) which has been shown to be
homologous with the plasma protein zinc-alpha(2)-glycoprotein (ZAG). The aim of
this study was to compare the ability of human ZAG with LMF to stimulate
lipolysis in vitro and induce loss of body fat in vivo, and to determine the
mechanisms involved. ZAG was purified from human plasma using a combination of Q
Sepharose and Superdex 75 chromatography, and was shown to stimulate glycerol
release from isolated murine epididymal adipocytes in a dose-dependent manner.
The effect was enhanced by the cyclic AMP phosphodiesterase inhibitor Ro20-1724,
and attenuated by freeze/thawing and the specific beta3-adrenoreceptor
antagonist SR59230A. In vivo ZAG caused highly significant, time-dependent,
decreases in body weight without a reduction in food and water intake. Body
composition analysis showed that loss of body weight could be attributed
entirely to the loss of body fat. Loss of adipose tissue may have been due to
the lipolytic effect of ZAG coupled with an increase in energy expenditure,
since there was a dose-dependent increase in expression of uncoupling protein-1
(UCP-1) in brown adipose tissue. These results suggest that ZAG may be effective
in the treatment of obesity.
PMID: 14984739 [PubMed]
48: Nutr Metab Cardiovasc Dis. 2003 Dec;13(6):349-56.
Relationships between changes in abdominal fat distribution and insulin
sensitivity during a very low calorie diet in abdominally obese men and women.
Laaksonen DE, Kainulainen S, Rissanen A, Niskanen L.
Department of Medicine, Kuopio University Hospital, Kuopio, Finland.
david.laaksonen@uku.fi
BACKGROUND AND AIM: Little is known about the association between abdominal
obesity and insulin sensitivity during rapid weight loss. We assessed the role
of visceral and subcutaneous fat as determinants of insulin sensitivity during
rapid weight loss in obese persons with the metabolic syndrome. METHODS AND
RESULTS: Twenty abdominally obese individuals [11 women and 9 men, body mass
index (BMI) 35.8+/-3.5 kg/m2] with the metabolic syndrome underwent a
very-low-calorie diet (VLCD) for nine weeks. At baseline, the computed
tomography (CT) measured area of total (r=-0.50, p=0.033) and visceral fat
tissue (r=-0.48, p=0.043), but not that of subcutaneous fat tissue (r=-0.34,
p=0.17), correlated with insulin sensitivity as assessed by the quantitative
insulin sensitivity check index after adjusting for sex and age. The 18 subjects
who completed the study lost 14.8 kg during the VLCD. Total, visceral and
subcutaneous abdominal fat tissue decreased by 22%, 29% and 17%, respectively.
The decrease in total (r=-0.51, p=0.035) and subcutaneous abdominal fat
(r=-0.57, p=0.017), but not visceral fat (r=0.11, p=0.68), correlated with the
increase in insulin sensitivity. Waist circumference did not offer any
additional information concerning abdominal fat distribution or insulin
sensitivity compared with that provided by BMI at baseline or after weight loss.
The waist/hip ratio was not associated with the CT measures of abdominal fat
distribution or insulin sensitivity. CONCLUSIONS: Total abdominal fat may be
more important than its compartmentalisation in abdominally obese individuals
with the metabolic syndrome. In this subgroup of individuals with obesity, the
measurement of waist circumference and the waist/hip ratio offered little
additional information over that provided by BMI at baseline or after weight
loss.
PMID: 14979681 [PubMed]
49: Endocrinology. 2004 Feb 19 [Epub ahead of print]
Fibroblast growth factor 19 increases metabolic rate and reverses dietary and
leptin deficient diabetes.
Fu L, John LM, Adams SH, Xian Yu X, Tomlinson E, Renz M, Mickey Williams P,
Soriano R, Corpuz R, Moffat B, Vandlen R, Simmons L, Foster J, Stephan JP, Ping
Tsai S, Stewart TA.
Departments of Molecular Biology, Protein Engineering and Assay Technologies,
Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080.
Hormonal control of metabolic rate can be important in regulating the imbalance
between energy intake and expenditure that underlies the development of obesity.
In mice fed a high fat diet, human fibroblast growth factor 19 (FGF19) increased
metabolic rate (1.53 +/- 0.06 L 02/hr/kg(0.75) (vehicle) vs. 1.93 +/- 0.05 L
02/hr/kg(0.75) (FGF19); P < 0.001) and decreased RQ (0.82 +/- 0.01 (vehicle) vs.
0.80 +/- 0.01 (FGF19); P < 0.05). In contrast to the vehicle treated mice that
gained weight (0.14 +/- 0.05 g/mouse/day), FGF19 treated mice lost weight (-0.13
+/- 0.03 g/mouse/day; P < 0.001) without a significant change in food intake.
Furthermore, in addition to a reduction in weight gain, treatment with FGF19
prevented or reversed the diabetes that develops in mice made obese by genetic
ablation of brown adipose tissue, or genetic absence of leptin. To explore the
mechanisms underlying the FGF19 mediated increase in metabolic rate, we profiled
the FGF19 induced gene expression changes in the liver and brown fat. In BAT,
chronic exposure to FGF19 led to a gene expression profile that is consistent
with activation of this tissue. We also found that FGF19 acutely increased liver
expression of the leptin receptor (1.8 fold; P < 0.05) and decreased the
expression of acetyl CoA carboxylase 2 (0.6 fold; P < 0.05). The gene expression
changes were consistent with the experimentally determined increase in fat
oxidation and decrease in liver triglycerides. Thus, FGF19 is able to increase
metabolic rate concurrently with an increase in fatty acid oxidation.
PMID: 14976145 [PubMed]
50: Ann Ital Med Int. 2003 Oct-Dec;18(4):238-45.
Body habitus changes, metabolic abnormalities, osteopenia and cardiovascular
risk in patients treated for human immunodeficiency virus infection.
Cirelli A, Cirelli G, Balsamo G, Masciangelo R, Stasolla A, Marini M.
S.S. Chemioantibioticoterapia Monitorizzata/AIDS, Dipartimento di Malattie
Infettive e Tropicali, Universita degli Studi "La Sapienza", Policlinico Umberto
I di Roma.
The aim of this study was to evaluate the influence of three variables--protease
inhibitors, stavudine, and the length of combined therapy--on body habitus
changes, metabolic effects and bone mineral density in HIV patients treated with
highly active antiretroviral therapy (HAART). The onset of possible
cardiovascular involvement was considered. Forty HIV patients (29 men and 11
women, mean age 39.13 +/- 7.82 years, range 28-61 years) treated with HAART for
12-43 months were evaluated for fat, lean, bone tissues, immunohematological and
cardiovascular alterations. The differences in fat/lean tissues and bone mineral
density were evaluated at dual-energy X-ray absorptiometry (DEXA). Serum lipids
and the CD4/CD8 T-cell counts were recorded. ECGs were taken every 6 months;
color Doppler echocardiography and color Doppler ultrasounds of the carotid
vessels were performed in close chronological sequence with the second DEXA.
Statistical analyses included: Student's t-test, Wilcoxon test, and
single-multiple regression analysis. Thirteen patients presented with fat loss,
7 fat accumulation, and 20 a combined form of both. The changes in the single
body districts showed that the decrease in the limb fat is to be attributed to
protease inhibitors, while none of the three variables was responsible for the
decrease in the upper limb fat. The trunk weight increase was not significant.
The decrease in the lean mass of the upper limbs is to be attributed to protease
inhibitors, while none of the three variables was responsible for the increase
in the lean mass of the upper and lower limbs. The decrease in bone mineral
density was not significant. No treatment-related cardiovascular lesions were
observed. In HIV patients treated with HAART for 12-43 months, the decrease in
lower limb fat was due to protease inhibitors. Neither osteopenia nor
cardiovascular diseases were observed during follow-up.
PMID: 14971712 [PubMed]
51: J Sports Sci. 2004 Jan;22(1):31-8.
Pre-exercise carbohydrate and fat ingestion: effects on metabolism and
performance.
Hargreaves M, Hawley JA, Jeukendrup A.
Centre for Physical Activity and Nutrition Research, School of Health Sciences,
Deakin University, Burwood, Vic 3125, Australia. mharg@deakin.edu.au
A key goal of pre-exercise nutritional strategies is to maximize carbohydrate
stores, thereby minimizing the ergolytic effects of carbohydrate depletion.
Increased dietary carbohydrate intake in the days before competition increases
muscle glycogen levels and enhances exercise performance in endurance events
lasting 90 min or more. Ingestion of carbohydrate 3-4 h before exercise
increases liver and muscle glycogen and enhances subsequent endurance exercise
performance. The effects of carbohydrate ingestion on blood glucose and free
fatty acid concentrations and carbohydrate oxidation during exercise persist for
at least 6 h. Although an increase in plasma insulin following carbohydrate
ingestion in the hour before exercise inhibits lipolysis and liver glucose
output, and can lead to transient hypoglycaemia during subsequent exercise in
susceptible individuals, there is no convincing evidence that this is always
associated with impaired exercise performance. However, individual experience
should inform individual practice. Interventions to increase fat availability
before exercise have been shown to reduce carbohydrate utilization during
exercise, but do not appear to have ergogenic benefits.
PMID: 14971431 [PubMed]
52: J Inherit Metab Dis. 2004;27(1):89-99.
The distribution of white blood cell fat oxidation in health and disease.
Pendergast DR, Fisher NM, Meksawan K, Doubrava M, Vladutiu GD.
Department of Physiology, University at Buffalo, Buffalo, New York 14214, USA.
dpenderg@buffalo.edu
Fat oxidation is important for maintaining health and for supplying energy for
exercise. We have proposed that the predisposition for individual rates of fat
oxidation is determined genetically but may be modulated by acute exercise or
exercise training. The purpose of this study was to examine cellular fat
oxidation in white blood cells (WBC) using [9,10-3H]palmitic acid. Sedentary
controls free of symptoms (SED-C, n=32), were compared with known carnitine
palmitoyltransferase (CPT) II-deficient patients (n =2), patients with fatiguing
diseases (chronic fatigue syndrome, CFS, n=6; multiple sclerosis, MS, n=31),
obesity (OB, n=5), eating disorders (ED, n=16), sedentary individuals prior to
and after exercise (SED-Ex, n=12), exercise-trained sedentary individuals
(SED-Tr, n=12), and elite runners (ER, n=5). Fat oxidation in WBC for all
subjects was normally distributed (mean=0.270 +/- 0.090 nmol/h per 10(9) WBC)
and ranged from 0.09 nmol/h per 10(9) WBC in CPT II-deficient patients to 0.59
nmol/h per 10(9) WBC in ER. There were no significant sex or acute exercise
effects on WBC fat oxidation. Patients with MS, OB or ED were not different from
SED-C; however, in CPT II-deficient patients, fat oxidation was low, while that
of CFS patients was high. Exercise training in SED-C resulted in a 16% increase
in fat oxidation but in ER it was still 97% higher than in SED-C. We propose
that while WBC fat oxidation is not significantly affected by sex or acute
exercise, and only by 15-20% with training, genetic factors play a role in
determining both high and low fat oxidation in certain groups of individuals.
The genetic predisposition for individual rates of fat oxidation may be easily
measured using WBC fat oxidation, as has been shown for CPT II-deficient
patients and for elite runners. Ranges of WBC fat oxidation that are abnormally
low (<20 nmol/h per 10(9) WBC, normal 20-35) or high (>35 nmol/h per 10(9) WBC)
are proposed based on genetic factors evaluated in this study.
PMID: 14970749 [PubMed]
53: J Appl Physiol. 2004 Feb 13 [Epub ahead of print]
Pyruvate dehydrogenase activation and kinase expression inhuman skeletal muscle
during fasting.
Spriet LL, Tunstall RJ, Watt MJ, Mehan KA, Hargreaves M, Cameron-Smith D.
Department of Human Biology and Nutritional Sciences, University of Guelph,
Guelph, Ontario, Canada.
Fasting forces adaptive changes in whole body and skeletal muscle metabolism
that increase fat oxidation and decrease the oxidation of carbohydrate. We
tested the hypothesis that 40 h of fasting would decrease pyruvate dehydrogenase
(PDH) activity and increase PDH kinase isoform (PDK1-4) mRNA expression in human
skeletal muscle. The putative transcriptional activators of PDK isozymes,
peroxisome proliferator-activated receptor alpha (PPARalpha) protein and
forkhead homolog in rhabdomyosarcoma (FKHR) mRNA were also measured. Eleven
healthy adults fasted following a standard meal (25% fat, 60% carbohydrate, 15%
protein) with blood and skeletal muscle samples taken at 3, 15, and 40 h post
prandial. Fasting increased plasma free fatty acid, glycerol and
beta-hydroxybutyrate concentrations and decreased glucose and insulin
concentrations. PDH activation decreased from 0.88 +/- 0.11 mmol
acetyl-CoA/min/kg wet muscle at 3 h to 0.62 +/- 0.10 (NS) and 0.39 +/- 0.06
(p<0.05) mmol/min/kg wet mass following 15 and 40 h of fasting. While all four
PDK isoforms were expressed in human skeletal muscle, PDK2 and 4 mRNA were the
most abundant. PDK1 and 3 mRNA abundance was ~ 1% and 15% of the PDK2 and PDK4
levels, respectively. The 40 h fast had no effect on PDK1, 2 and 3 mRNA
expression. PDK4 mRNA was significantly increased ~3-fold after 15 h and
~14-fold after 40 h of fasting. Skeletal muscle PPARalpha protein and FKHR mRNA
abundance were unaffected by the fast. The results suggest that decreased PDH
activation following 40 h of fasting may have been a function of the large
increase in PDK4 mRNA expression and possible subsequent increase in PDK protein
and activity. The changes in PDK4 expression and PDH activity did not coincide
with increases in the transcriptional activators, PPARalpha and FKHR.
PMID: 14966024 [PubMed]
54: J Endocrinol Invest. 2003 Sep;26(9):902-10.
Effects of estrogen replacement on metabolic factors that influence physical
performance in female hypogonadism.
Kohrt WM, Van Pelt RE, Gozansky WS.
Division of Geriatric Medicine, Department of Medicine, University of Colorado
Health Sciences Center, Denver, Colorado 80262, USA. wendy.kohrt@uchsc.edu
There is a lack of knowledge regarding the effects of estrogens on physical
performance. This is related, in part, to the challenge of isolating the effects
of estrogens from those of progestins, because levels of both hormones fluctuate
across the menstrual cycle, both decline during the menopausal transition, and
the administration oh hormones to hypogonadal women typically involves a
combination of estrogens and progestins. Some research findings suggest that
fluctuations in estrogen levels acutely influence factors that may affect
physical performance, such as substrate utilization or maximal aerobic power,
but solid evidence is lacking. The simple observation that hypogonadism is not
uncommon among elite athletes in some sports suggests that estrogen deficiency
does not have a major negative impact on athletic performance. However, chronic
hypogonadism may ultimately lead to impaired performance by menas that are not
necessarily obvious. For example, chronic estrogen deficiency has potent,
deleterious effects on the skeleton that can increase risk for stress fracture
and may limit the ability to sustain a high level of physical training. Estrogen
deficiency also appears to promote fat accumulation and may accelerate the loss
of fat-free mass, and both of these changes in body composition could impair
physical performance. There is evidence that hormone replacement attenuates the
negative effects of hypogonadism on body composition and bone density, and that
effects are mediated primarily by estrogens rather than progestins. Further
research is necessary to broaden the understanding of the role of the estrogens
in physical performance.
PMID: 14964444 [PubMed]
55: J Endocrinol Invest. 2003 Sep;26(9):893-901.
Body composition and muscle performance during menopause and hormone replacement
therapy.
Sipila S.
Department of Health Sciences, University of Jyvaskyla, Finland.
sipila@sport.jyu.fi
Menopausal transition is characterized by ovarian failure and its consequent
decrease in female sex steroid production. Earlier studies suggest that an
increase and redistribution of body fat during menopause predispose women to
cardiovascular disease and metabolic syndrome. In addition, peri- and
post-menopausal women seem to have less lean body mass (LBM) compared with
pre-menopausal women. Accordingly, a changing ovarian hormonal status may
accelerate the loss of muscle mass and result in decreased muscle performance
and functional capacity. Hormone replacement therapy (HRT) has been used to
treat menopausal symptoms and as a primary prevention therapy in chronic
conditions. Inconsistent findings have, however, been published on the effects
of HRT on body composition in post-menopausal women. Some studies clearly
suggest that HRT counteracts menopause-related changes in body composition
whereas others fail to show any difference between post-menopausal HRT users and
abstainers. Although cross-sectional studies show conflicting results concerning
the association between HRT and muscle performance, experimental trials suggest
that deterioration in muscle force during menopause can be prevented by HRT. In
the future, longitudinal data need to be collected to confirm changes in body
composition and muscle performance during menopausal transition irrespective of
age. Although HRT seems to have beneficial effects on body composition and
muscle performance in healthy post-menopausal women, there is considerable
variation in the effects of HRT between different studies. The underlying
mechanism of HRT action on muscle performance is still unclear.
PMID: 14964443 [PubMed]
56: Adv Ther. 2003 Sep-Oct;20(5):270-81.
Master Amino acid Pattern as sole and total substitute for dietary proteins
during a weight-loss diet to achieve the body's nitrogen balance equilibrium.
Luca-Moretti M, Grandi A, Luca E, Muratori G, Nofroni MG, Mucci MP, Gambetta P,
Stimolo R, Drago P, Giudice G, Tamburlin N, Karbalai M, Valente C, Moras G.
American Nutrition Clinics, Coral Gables, FL 33143, USA.
Results of this multicentric study have shown that by giving Master Amino acid
Pattern (MAP) as a sole and total substitute of dietary proteins to 500
overweight participants undergoing the American Nutrition Clinics/Overweight
Management Program (ANC/OMP), the participants' body nitrogen balance could be
maintained in equilibrium with essentially no calories (MAP 1 g=0.04 kcal),
thereby preserving the body's structural and functional proteins, eliminating
excessive water retention from the interstitial compartment, and preventing the
sudden weight increase after study conclusion commonly known as the yo-yo
effect. Study results have shown that the use of MAP, in conjunction with the
ANC/OMP regimen, has proven to be safe and effective by preventing those adverse
effects associated with a negative nitrogen balance, such as oversized or flabby
tissue, stretch marks, the sagging of breast tissue, increased hair loss, faded
hair color, and fragile or brittle nails. Also prevented were those anomalies
commonly associated with weight-loss diets, such as hunger, weakness, headache
caused by ketosis, constipation, and decreased libido. The use of MAP in
conjunction with the ANC/OMP also allowed for mean weight loss of 2.5 kg (5.5
lb) per week, achieved through reduction of excessive fat tissue and elimination
of excessive water retention from the interstitial compartment.
Publication Types:
Clinical Trial
Multicenter Study
PMID: 14964347 [PubMed]
57: Dev Cell. 2004 Feb;6(2):241-51.
Comment in:
Dev Cell. 2004 Feb;6(2):163-4.
Drosophila cyclin D/Cdk4 requires Hif-1 prolyl hydroxylase to drive cell growth.
Frei C, Edgar BA.
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, P.O. Box
19024, Seattle, WA 98109, USA. christian.frei@zool.unizh.ch
The Drosophila cyclin-dependent protein kinase complex Cyclin D/Cdk4 induces
cell growth (accumulation of mass) as well as proliferation (cell cycle
progression). To understand how CycD/Cdk4 promotes growth, we performed a screen
for modifiers of CycD/Cdk4-driven overgrowth in the eye. Loss-of-function
mutations in Hif-1 prolyl hydroxylase (Hph), an enzyme involved in the cellular
response to hypoxic stress, dominantly suppress the growth but not the
proliferation function of CycD/Cdk4. hph mutant cells are defective for growth,
and, remarkably, ectopic expression of Hph is sufficient to increase cellular
growth. Epistasis analysis places Hph downstream of CycD/Cdk4. Overexpressed
CycD/Cdk4 causes an increase in Hph protein in tissues where Hph induces growth,
suggesting a mechanism whereby Hph levels are regulated posttranscriptionally in
response to CycD/Cdk4. Our data suggest that Hph, in addition to its function in
hypoxic response, is a regulator of cellular growth and that it is a key
mediator for CycD/Cdk4.
PMID: 14960278 [PubMed]
58: Proc Natl Acad Sci U S A. 2004 Feb 17;101(7):2058-63. Epub 2004 Feb 09.
Rapid transformation of white adipocytes into fat-oxidizing machines.
Orci L, Cook WS, Ravazzola M, Wang MY, Park BH, Montesano R, Unger RH.
Department of Morphology, University of Geneva Medical School, Rue Michel Servet
1, CH 1211 Geneva 4, Switzerland. lelio.orci@medecine.unige.ch
Adenovirus-induced hyperleptinemia rapidly depletes body fat in normal rats
without increasing free fatty acids and ketogenesis, implying that fat-storing
adipocytes are oxidizing the fat. To analyze the ultrastructural changes of
adipocytes accompanying this functional transformation, we examined the fat
tissue by electron microscopy. After 14 days of hyperleptinemia, adipocytes had
become shrunken, fatless, and encased in a thick basement-membrane-like matrix.
They were crowded with mitochondria that were much smaller than those of brown
adipocytes. Their gene expression profile revealed striking up-regulation of
peroxisome proliferator-activated receptor gamma coactivator 1alpha (an
up-regulator of mitochondrial biogenesis not normally expressed in white fat),
increased uncoupling proteins-1 and -2, and down-regulation of lipogenic
enzymes. Phosphorylation of both acetyl CoA carboxylase and AMP-activated
protein kinase was increased, thus explaining the increase in fatty acid
oxidation. The ability to transform adipocytes into unique fat-burning cells may
suggest novel therapeutic strategies for obesity.
PMID: 14769942 [PubMed]
59: Maturitas. 2004 Feb 20;47(2):99-105.
Relationship between soft tissue body composition and bone mass in
perimenopausal women.
Li S, Wagner R, Holm K, Lehotsky J, Zinaman MJ.
Loyola University, Chicago, IL 60153, USA. sli@luc.edu
OBJECTIVES: Perimenopause, the transition into menopause, marks the beginning of
accelerated bone loss, contributing to the development of osteoporosis, a major
public health problem. This perimenopausal transition has also been associated
with a decrease in body lean mass, an increase in fat mass, and an increase in
body weight. How these changes in fat mass and lean mass may influence bone
mineral density (BMD) is currently unknown. The purpose of this study is to
determine the independent effect and relative contribution of lean mass and fat
mass to BMD in perimenopausal women. MATERIAL AND METHODS: The sample consisted
of 43 sedentary perimenopausal women (age: mean = 49.6; S.D. = 3.2) with an
intact uterus and ovaries, participating in a study of exercise and
perimenopausal symptoms. Total body BMD, regional BMD, and soft tissue body
composition were measured by dual-energy X-ray absorptiometry. Other measures
including age, height, weight, and serum FSH and E2 were also obtained. RESULTS:
Findings revealed that 14% of these perimenopausal women had low bone mass
(osteopenia) in the lumbar spine and/or the femoral neck. Overall body fat mass
and lean mass had positive relationships with BMD of lumber spine and the femur.
However, using multiple regression analyses, only lean mass and ethnicity
remained significant predictors for BMD of the femoral neck (r2 = 45%) with lean
mass explaining more variance than ethnicity. Lean mass was the sole predictor
of total proximal femur BMD explaining 38% of the variance. Fat mass was not a
significant predictor of BMD at any skeleton site. CONCLUSIONS: These findings
suggest that body lean mass, not fat mass, is a significant contributor to
femoral BMD in perimenopausal women.
PMID: 14757268 [PubMed]
60: Br J Nutr. 2004 Feb;91(2):245-52.
The acute effects of olive oil v. cream on postprandial thermogenesis and
substrate oxidation in postmenopausal women.
Soares MJ, Cummings SJ, Mamo JC, Kenrick M, Piers LS.
Department of Nutrition, Dietetics and Food Science, School of Public Health,
Curtin University of Technology, GPO Box U 1987, Perth WA 6845, Australia.
m.soares@curtin.edu.au
The influence of the source of dietary fat on postprandial thermogenesis and
substrate oxidation rates, was examined in twelve postmenopausal women aged
57-73 years, with BMI 21.9-38.3 kg/m(2). A single blind, randomised, paired
comparison of two high-fat, isoenergetic, mixed test meals was conducted. The
major source of fat was either cream (CREAM) or extra virgin olive oil (EVOO).
RMR, diet-induced thermogenesis (DIT) and substrate oxidation rates over 5 h
were measured by indirect calorimetry. There were no differences in body weight,
RMR, fasting carbohydrate or fat oxidation rates between the two occasions. DIT
(EVOO 97 (SD 46) v. CREAM 76 (SD 69) kJ/5 h and EVOO 5.2 (SD 2.5) v. CREAM 4.1
(SD 3.7)% energy) did not differ between the two test meals. The postprandial
increase in carbohydrate oxidation rates, relative to their respective fasting
values (DeltaCOX), was significantly lower following the EVOO meal (EVOO 10.6
(SD 8.3) v. CREAM 17.5 (SD 10) g/5 h; paired t test, P=0.023), while
postprandial fat oxidation rates (DeltaFOX) were significantly higher (EVOO 0.0
(SD 4.4) v. CREAM -3.6 (sd 4.0) g/5 h; P=0.028). In the eight obese subjects,
however, DIT was significantly higher following the EVOO meal (EVOO 5.1 (SD 2.0)
v. CREAM 2.5 (sd 2.9) %; P=0.01). This was accompanied by a significantly lower
DeltaCOX (EVOO 10.9 (SD 9.9) v. CREAM 17.3 (SD 10.5) g/5 h; P=0.03) and
significantly higher DeltaFOX (EVOO 0.11 (SD 4.4) v. CREAM -4.1 (SD 4.5) g/5 h,
P=0.034). The present study showed that olive oil significantly promoted
postprandial fat oxidation and stimulated DIT in abdominally obese
postmenopausal women.
Publication Types:
Clinical Trial
Randomized Controlled Trial
PMID: 14756910 [PubMed]
61: J Agric Food Chem. 2004 Feb 11;52(3):587-91.
Effect of antioxidants on oxidative stability of edible fats and oils:
thermogravimetric analysis.
van Aardt M, Duncan SE, Long TE, O'Keefe SF, Marcy JE, Sims SR.
Department of Food Science and Technology, Virginia Polytechnic Institute and
State University, Duck Pond Drive, Blacksburg, Virginia 24061, USA.
mvanaard@vt.edu
Thermogravimetric analysis was used to determine the oxidative stability of
various edible oils (olive oil, milkfat) and triacylglycerides (triolein,
trilinolein), while the effect of natural (alpha-tocopherol, ascorbic acid) and
synthetic antioxidants (butylated hydroxytoluene (BHT), butylated hydroxyanisole
(BHA), and tertiary butyl hydroquinone were evaluated by addition to
trilinolein. Oil resistance to oxidation was obtained by measuring the increase
in sample weight due to the uptake of molecular oxygen, the temperature at
maximum sample weight, and the temperature at the onset of oxidation. When
comparing sample weight increase, trilinolein proved to be oxidatively less
stable than triolein, olive oil, and milk fat, while triolein was less stable
than olive oil and milk fat. Olive oil showed significantly higher stability
than milkfat when comparing the temperature at the onset of oxidation. When
comparing effectiveness of antioxidants, a combination of 0.01% BHA and 0.01%
BHT increased trilinolein stability the most.
PMID: 14759153 [PubMed]
62: Int J Sports Med. 2004 Jan;25(1):32-7.
Relation between plasma lactate concentration and fat oxidation rates over a
wide range of exercise intensities.
Achten J, Jeukendrup AE.
School of Sport and Exercise Sciences, University of Birmingham, Edgbaston,
Birmingham B15 2TT, United Kingdom.
Increasing exercise intensities will induce an increase in glycolytic flux. High
glycolytic activity is associated with reduced fat oxidation rates and increased
accumulation of lactate. Both lactate and hydrogen ions have been shown to be
directly related to the decreased fat oxidation rates. The aim of the present
study was to determine whether the exercise intensity at which maximal fat
oxidation rates occur coincides with the intensity at which lactate starts to
accumulate in plasma. Thirty-three moderately trained endurance athletes
performed a graded exercise test to exhaustion on a cycle-ergometer with 35 W
increments every three minutes. Expired gas analysis was performed throughout
the test and stoichiometric equations were used to calculate fat oxidation
rates. The intensity which elicited maximal fat oxidation (Fat (max)) and the
intensity at which fat oxidation rates became negligible (Fat (min)) were
determined. Blood samples for lactate analysis were collected at the end of each
stage of the graded exercise test. The intensity at which lactate concentration
increased above baseline (LIAB) and the lactate threshold (LT-D) were determined
(D-max method). Fat (max) was located at 63 +/- 9 % V.O (2)max and LIAB at 61
+/- 5 % V.O (2)max and there appeared to be no statistical difference between
the two intensities. Fat (max) and LIAB were significantly correlated. Fat (min)
and LT-D were also significantly correlated but were located at different
intensities (82 +/- 7 and 87 +/- 9 % V.O (2)max respectively). The data of the
present study showed that accumulation of lactate in plasma is strongly
correlated to the reduction seen in fatty acid oxidation with increasing
exercise intensities. The first rise of lactate concentration occurred at the
same intensity as the intensity which elicited maximal fat oxidation rates.
PMID: 14750010 [PubMed]
63: Eur J Clin Nutr. 2004 Feb;58(2):244-9.
Effects of elderberry juice on fasting and postprandial serum lipids and
low-density lipoprotein oxidation in healthy volunteers: a randomized,
double-blind, placebo-controlled study.
Murkovic M, Abuja PM, Bergmann AR, Zirngast A, Adam U, Winklhofer-Roob BM,
Toplak H.
Department of Food Chemistry and Technology, Graz University of Technology,
Graz, Austria. michael.murkovic@tugraz.at
BACKGROUND: In a recent pilot study, the intake of elderberry juice resulted in
a significant decrease in serum cholesterol concentrations and an increase in
low-density lipoprotein (LDL) stability. This study was designed to verify the
preliminary results. OBJECTIVE: We investigated the impact of elderberry juice
on cholesterol and triglyceride concentrations as well as antioxidant status in
a cohort of young volunteers. DESIGN: Study A: The randomized,
placebo-controlled trial for studying the effect of anthocyanes on lipid and
antioxidant status, 34 subjects took capsules with 400 mg spray-dried powder
containing 10% anthocyanes t.i.d. equivalent to 5 ml elderberry juice for 2
weeks. A subgroup of 14 subjects continued for an additional week to test for
resistance to oxidation of LDL. Study B: To investigate the short-te