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1.
We have reviewed the published literature regarding the effects of CLA on body composition and immune cell functions in humans
and in animal models. Results from studies in mice, hamsters, rats, and pigs generally support the notion that CLA reduced
depot fat in the normal or lean strains. However, in obese rats, it increased body fat or decreased it less than in the corresponding
lean controls. These studies also indicate that t10,c12-CLA was the isomer that reduced adipose fat; however, it also increased the fat content of several other tissues and increased
circulating insulin and the saturated FA content of adipose tissue and muscle. Four of the eight published human studies found
small but significant reductions in body fat with CLA supplementation; however, the reductions were smaller than the prediction
errors for the methods used. The other four human studies found no change in body fat with CLA supplementation. These studies
also report that CLA supplementation increased the risk factors for diabetes and cardiovascular disease including increased
blood glucose, insulin, insulin resistance, VLDL, C-reactive protein, lipid peroxidation, and decreased HDL. Most studies
regarding the effects of CLA on immune cell functions have been conducted with a mixture of isomers, and the results have
been variable. One study conducted in mice with the purified c9,t11-CLA and t10,c12-CLA isomers indicated that the two isomers have similar effects on immune cell functions. Some of the reasons for the discrepancies
between the effects of CLA in published reports are discussed. Although significant benefit to humans from CLA supplementation
is questionable, it may create several health risks in both humans and animals. On the basis of the published data, CLA supplementation
of adult human diets to improve body composition or enhance immune functions cannot be recommended at this time. 相似文献
2.
Recent animal studies have demonstrated that dietary conjugated linoleic acid (CLA) reduces body fat and that this decrease
may be due to a change in energy expenditure. The present study examined the effect of CLA supplementation on body composition
and energy expenditure in healthy, adult women. Seventeen women were fed either a CLA capsule (3 g/d) or a sunflower oil placebo
for 64 d following a baseline period of 30 d. The subjects were confined to a metabolic suite for the entire 94 d study where
diet and activity were controlled and held constant. Change in fat-free mass, fat mass, and percentage body fat were unaffected
by CLA supplementation (0.18±0.43 vs. 0.09±0.35 kg; 0.01±0.64 vs. −0.19±0.53 kg; 0.05±0.62 vs. −0.67±0.51%, placebo vs. CLA,
respectively). Likewise, body weight was not significantly different in the placebo vs. the CLA group (0.48±0.55 vs. −0.24±0.46
kg change). Energy expenditure (kcal/min), fat oxidation, and respiratory exchange ratio were measured once during the baseline
period and during weeks 4 and 8 of the intervention period. At all three times, measurements were taken while resting and
walking. CLA had no significant effect on energy expenditure, fat oxidation, or respiratory exchange ratio at rest or during
exercise. When dietary intake was controlled, 64 d of CLA supplementation at 3 g/d had no significant effect on body composition
or energy expenditure in adult women, which contrasts with previous findings in animals. 相似文献
3.
Christian von Loeffelholz Jürgen Kratzsch Gerhard Jahreis 《European Journal of Lipid Science and Technology》2003,105(6):251-259
Conjugated linoleic acids (CLA) are believed to influence body composition, blood lipids and certain endocrine parameters in animals and humans. The aim of this study was to investigate the effects of a six months dietary supplementation of 7 g CLA‐oil (containing 54% CLA) daily in two groups of male and female resistance‐trained athletes who were at a different training stage. The volunteers were matched according to their previous training: 7 beginners (3♀/4♂) and 7 advanced athletes (2♀/5♂). During the intervention period they performed a standardized training routine three times per week. Blood samples were taken and body mass index, body composition (bioelectrical impedance assessment) and nutrient intake (7‐day food record) were recorded at baseline as well as during and following dietary supplementation Results: Serum lipid concentrations, serum leptin, soluble leptin receptor and IGF‐I levels or body composition were similar in the two categories of athletes after CLA supplementation. However, despite a higher energy intake, a significant reduction of body fat (P <0.05) was observed and both groups tended to increase their body cell mass (not significant). Total body water increased in the novice athletes (P <0.05). Furthermore, total cholesterol (P = 0.049) increased over baseline levels in the novice athletes. These levels remained within the physiological range. In all athletes there was a significant correlation between percentage body fat and leptin (baseline: r2 = 0.46, P = 0.01, CLA: r2 = 0.49, P = 0.011), as well as between fat mass and serum leptin levels (baseline: r2 = 0.35, P = 0.033, CLA: r2 = 0.60, P = 0.002). Conclusions: Over a period of six months no differences were observed in the effects of a commercial CLA‐triacylglyceride (54% CLA, 7g/d) on selected endocrine parameters, blood lipids, food intake and body composition between advanced and novice resistance‐trained athletes who take part in a regular training program. 相似文献
4.
Conjugated linoleic acid and chromium lower body weight and visceral fat mass in high-fat-diet-fed mice 总被引:1,自引:1,他引:0
More than half of the U.S. population has a body mass index of 25 kg/m2 or more, which classifies them as overweight or obese. Obesity is often associated with comorbidities such as diabetes, cardiovascular
diseases, and cancer. CLA and chromium have emerged as major dietary supplements that reduce body weight and fat mass, and
increase basal metabolic rate in animal models. However, studies show that CLA induces insulin resistance in mice and in humans,
whereas Cr improves insulin sensitivity. Hence, we designed the present study to examine the combined effect of CLA and Cr
on body composition and insulin sensitivity in a Balb/c mice (n=10/group) model of high-fat-diet-induced obesity. CLA alone lowered body weight, total body fat mass, and visceral fat mass,
the last of which decreased further with the combination of CLA and Cr. This effect was accompanied by decreased serum leptin
levels in CLA-fed and CLA+Cr-fed mice, and by higher energy expenditure (EE) and oxygen consumption (OC) in CLA+Cr-fed mice.
Serum levels of glucose, insulin, the pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6),
as well as insulin resistance index (IRI), decreased with CLA, whereas CLA and Cr in combination had significant effects on
insulin and IL-6 concentrations and IRI. In summary, CLA+Cr decreased body weight and fat mass in high-fat-diet-fed mice,
which may be associated with decreased leptin levels and higher EE and OC. 相似文献
5.
Conjugated linoleic acid supplementation in humans: Effects on circulating leptin concentrations and appetite 总被引:3,自引:0,他引:3
Medina EA Horn WF Keim NL Havel PJ Benito P Kelley DS Nelson GJ Erickson KL 《Lipids》2000,35(7):783-788
Conjugated linoleic acid (CLA) has been demonstrated to reduce body fat in animals. However, the mechanism by which this reduction
occurs is unknown. Leptin may mediate the effect of CLA to decrease body fat. We assessed the effects of 64 d of CLA supplementation
(3 g/d) on circulating leptin, insulin, glucose, and lactate concentrations in healthy women. Appetite was assessed as a physiological
correlate of changes in circulating leptin levels. Analysis of plasma leptin concentrations adjusted for adiposity by using
fat mass as a covariate showed that CLA supplementation significantly decreased circulating leptin concentrations in the absence
of any changes of fat mass. Mean leptin levels decreased over the first 7 wk and then returned to baseline levels over the
last 2 wk of the study in the CLA-treated group. Appetite parameters measured at around the time when the greatest decreases
in leptin levels were observed showed no significant differences between supplementation and baseline determinations in the
CLA-supplemented group or between the CLA and placebo-supplemented groups. There was a nonsignificant trend for mean insulin
levels to increase toward the end of the supplementation period in CLA-treated subjects. CLA did not affect plasma glucose
and lactate over the treatment period. Thus, 64 d of CLA supplementation in women produced a transient decrease in leptin
levels but did not alter appetite. CLA did not affect these parameters in a manner that promoted decreases of adiposity. 相似文献
6.
Supplementation with CLA: Isomer incorporation into serum lipids and effect on body fat of women 总被引:5,自引:5,他引:0
Animal studies have suggested that CLA, a natural component of meat and dairy products, may confer beneficial effects on health.
However, human studies using supplementation with CLA have produced contradictory results. The aim of the present study was
to further investigate the effect of CLA supplementation on human body fat, serum leptin, and serum lipids, as well as the
incorporation of CLA isomers into serum lipids classes. Sixteen young healthy nonobese sedentary women received 2.1 g of CLA
(divided equally between the cis,trans-9,11 and trans,cis-10,12 isomers) daily for 45 d and placebo for 45 d in a randomized double-blind crossover design. Body fat was estimated
(by measurement of skinfold thickness at 10 sites), and blood was sampled at the beginning, middle, and end of the entire
intervention period; an additional blood sample was obtained 2 wk thereafer. No significant differences in energy, carbohydrate,
lipid, or protein intake existed between the CLA and placebo intake periods. No significant differences were found in body
fat or serum leptin, TAG, total cholesterol, HDL-cholesterol, and alanine aminotransferase between CLA and placebo. The CLA
isomer content of serum TAG, phospholipids, and total lipids increased 2–5 times with CLA supplementation (P<0.05). In contrast, the CLA content of cholesteryl esters did not change significantly. The period of 2 wk after the end
of CLA supplementation was sufficient for its washout from serum lipids. These data indicate that supplementation with 2.1
g of CLA daily for 45 d increased its levels in blood but had no effect on body composition or the lipidemic profile of nonobese
women. 相似文献
7.
Supplementation with conjugated linoleic acid (CLA) induces a number of physiological effects in experimental animals, including
reduced body fat content, decreased aortic lipid deposition, and improved serum lipid profile. Controlled trials on the effects
of CLA in humans have hitherto been scarce. The aim of this study was to evaluate the effects of supplementation with CLA
in healthy humans on anthropometric and metabolic variables and on the fatty acid composition of serum lipids and thrombocytes.
Fifty-three healthy men and women, aged 23–63 yr, were randomly assigned to supplementation with CLA (4.2 g/d) or the same
amount of olive oil during 12 wk in a double-blind fashion. The proportion of body fat decreased (−3.8%, P<0.001) in the CLA-treated group, with a significant difference from the control group (P=0.050). Body weight, body mass index, and sagittal abdominal diameter were unchanged. There were no major differences between
the groups in serum lipoproteins, nonesterified fatty acids, plasma insulin, blood glucose, or plasminogen activator inhibitor
1 (PAI-1). In the CLA group the proportions of stearic, docosatetraenoic, and docosapentaenoic acids increased in serum lipids
and thrombocytes, while proportions of palmitic, oleic, and dihomoγ-linolenic acids decreased, causing a decrease of the estimated
Δ-6 and Δ-9 and an increase in the Δ-5 desaturase activities. These results suggest that supplementation with CLA may reduce
the proportion of body fat in humans and that CLA affects fatty acid metabolism. No effects on body weight, serum lipids,
glucose metabolism, or PAI-1 were seen. 相似文献
8.
Prais Botelho A Santos-Zago LF Costa de Oliveira A 《Archivos latinoamericanos de nutrición》2008,58(2):156-163
Dietary supplementation with conjugated linoleic acid (CLA) may reduce body fat mass and increase lean body mass in various species. The objective of this study was to study the effects of conjugated linoleic acid (CLA) supplementation on body composition, serum leptin and triacylglycerol levels in Wistar rats. Rats received linoleic acid (group C) or conjugated linoleic acid (group AE, supplemented with AdvantEdge CLA, and group CO, supplemented with CLA One) in the concentrations of 2% of daily feed consumption. Serum leptin and triacylglycerol levels of rats were measured by means of commercial kits. After 42 days of supplementation, rats in the control group exhibited body fat contents of 53.94 +/- 6.80 g, and those in groups AE and CO had 45.43 +/- 4.86 g and 43.75 +/- 1.93 g, respectively, corresponding to a mean body fat reduction of 18%. Water, whole body protein and ash contents of rats supplemented with CLA were statistically higher relative to control group content (corresponding to a mean increasing of 7.65%; 6.5% and 12.35%, respectively). Experimental groups AE and CO, which received CLA supplementation, had statistically lower serum leptin levels (3.45 +/- 0.46 ng/mL and 3.08 +/- 0.19 ng/mL, respectively) relative to the control group (4.21 +/- 0.22 ng/mL) which received linoleic acid. Triacylglycerol levels did not change after CLA supplementation (p > 0.05). Supplementation with conjugated linoleic acid in the concentration of 2% of mean daily feed consumption was able to change body composition of rats after 42 days of experimentation. 相似文献
9.
Grethe Berven Amund Bye Ottar Hals Henrietta Blankson Hans Fagertun Erling Thom Jan Wadstein Ola Gudmundsen 《European Journal of Lipid Science and Technology》2000,102(7):455-462
The main objective of the study was to investigate the safety of conjugated linoleic acid (CLA) in healthy volunteers. The effect of CLA on body composition was also investigated. The trial design was a randomized, double‐blind placebo controlled study including 60 overweight or obese volunteers (body mass index (BMI) 27.5—39.0 kg/m2). The subjects were divided into two groups receiving 3.4 g CLA or placebo (4.5 g olive oil) daily for 12 weeks. The safety was evaluated by analysis of blood parameters and by clinical examinations at baseline and week 12. Vital signs and adverse events were registered at baseline, week 6, and week 12. Bio Impedance Assessment was applied for body composition measurements. 55 subjects completed the study. Adverse events occurred in 10% of the subjects. No difference in adverse events or other safety parameters was found between the treatment groups. Small changes in the laboratory safety data were not regarded as clinically significant. Moreover, no clinically significant changes in vital signs were observed in any of the groups. In the CLA group, mean weight was reduced by 1.1 kg (paired t‐test p = 0.005), while mean BMI was reduced by 0.4 kg/m2(p = 0.007). However, the overall treatment effect of CLA on body weight and BMI was not significant. There were no differences found between the groups with regard to efficacy parameters. The results indicate that CLA in the given dose is a safe substance in healthy populations with regard to the safety parameters investigated. 相似文献
10.
CLA and body weight regulation in humans 总被引:3,自引:0,他引:3
CLA comprises a group of unsaturated FA isomers with a variety of biological effects in experimental animals. CLA reduces
body fat accumulation in animal models and has been suggested to have significant effects on lipid and glucose metabolism,
e.g., antidiabetic effects in obese Zucker rats. It has been proposed that the trans10-cis12 isomer is the active isomer associated with the antiobesity and insulin-sensitizing properties of CLA. The metabolic effects
in humans in general, and isomer-specific effects specifically, are not well characterized. In a series of controlled studies
in humans, we investigated the effects of CLA (given as the commercially available mixture of isomers and as the purified
trans10-cis12 CLA isomer) on anthropometry, lipid and glucose metabolism, and markers of lipid peroxidation. Preliminary results indicate
that CLA may slightly decrease body fat in humans also, particularly abdominal fat, but there is no effect on body weight
or body mass index. There is no simultaneous improvement in lipid or glucose metabolism. Rather, the trans10-cis12 CLA isomer unexpectedly caused significant impairment of the peripheral insulin sensitivity as well as of blood glucose
and serum lipid levels. In addition, CLA markedly elevated lipid peroxidation. Thus, the metabolic effects of CLA in human
seem complex; further studies, especially of isomer-specific effects and for longer time periods, are warranted. 相似文献
11.
Anke Jaudszus Katrin Kuhnt Carsten Rohrer Gerhard Jahreis 《European Journal of Lipid Science and Technology》2010,112(12):1393-1396
We analyzed a triacylgylcerol esterified CLA preparation characteristically rich in c9,t11‐CLA and free of t10,c12‐CLA three times within a period of 2${1 \over 2}$ years by GC and silver ion‐HPLC. For the first time, we present data on the long‐term stability of this preparation with regard to the fatty acid profile and the isomeric composition of CLA under certain storage conditions, providing useful information for the planning of long‐term trials. 相似文献
12.
The effect of conjugated linoleic acid on plasma lipoproteins and tissue fatty acid composition in humans 总被引:3,自引:10,他引:3
Conjugated linoleic acid (CLA) has been suggested by some animal studies to possess antiatherogenic properties. To determine,
in humans, the effect of dietary CLA on blood lipids, lipoproteins, and tissue fatty acid composition, we conducted a 93-d
study with 17 healthy female volunteers at the Metabolic Research Unit of the Western Human Nutrition Research Center. Throughout
the study, subjects were fed a low-fat diet [30 energy percent (en%) fat, 19 en% protein, and 51 en% carbohydrate] that consisted
of natural foods with the recommended dietary allowances for all known nutrients. After a 30-d stabilization period, subjects
were randomly assigned to either an intervention group (n=10) supplemented daily with capsules containing 3.9 g of CLA or a control group (n=7) that received an equivalent amount of sunflower oil. The CIA capsules (CLA 65%) contained four major cis/trans geometric isomers (11.4% 9 cis-,11 trans-18∶2; 10.8% 8 trans-,10 cis-18∶2; 15.3% 11 cis-,13 trans-18∶2; and 14.7% 10 trans-, 12 cis-18∶2) and their corresponding cis/cis (6.74% total) and trans/trans (5.99% total) varieties in smaller amounts. Fasting blood was drawn on study days 30 (end of the stabilization period), 60
(midpoint of the intervention period), and 93 (end of the intervention period). Adipose tissue samples were taken on days
30 and 93. CLA supplementation for 63 d did not change the levels of plasma cholesterol, low density lipoprotein cholesterol,
high density lipoprotein cholesterol, and triglycerides. The weight percentage of CLA in plasma increased from 0.28±0.06 to
1.09±0.31 (n=10, P<0.05) after the supplementation. The 9 cis-,11 trans-isomer was the most prominent variety followed by the 11 cis-,13 trans- and 10 trans-,12 cis-isomers in lesser amounts. CLA in adipose tissue was not influenced by the supplementation (0.79±0.18 to 0.83±0.19 wt%) (n=10) and the 9 cis-,11 trans-variety was the only isomer present. Thus, contrary to findings from some animal studies, CLA does not seem to offer health
benefits, in the short term, regarding the prevention of atherosclerosis in humans. CLA supplementation for 2 mon did not
alter the blood cholesterol or lipoprotein levels of healthy, normolipidemic subjects. The supplementation did increase CLA
in the plasma but only 4.23% of the ingested CLA was present in the plasma at any given time. No adverse effect of CLA supplementation
was detected in this study. 相似文献
13.
Gerhard Jahreis Jana Kraft Frank Tischendorf Friedrich Schne Christian von Loeffelholz 《European Journal of Lipid Science and Technology》2000,102(11):695-703
Institute of Nutrition, Friedrich Schiller University of Jena, Jena, Germany In the last decade, conjugated linoleic acids (CLA) have been shown to have some beneficial (but also unfavourable) effects: anticarcinogenic properties, immune modulation, reduction of body fat and increase of lean body mass, normalisation of impaired glucose tolerance, promotion of fatty streak formation, and isomer‐specific effects. The research base on CLA has been derived almost exclusively from animal models, while some of the biological properties have been fairly well‐documented, others are still open to question. For about 5 years a lot of commercial CLA mixtures have been offered. These mixtures produced from linoleic acid‐rich oil like sunflower or safflower oil by alkali isomerization contained, besides cis‐9,trans‐11 and trans‐10,cis‐12 CLA isomers (about 20—40% of each), parts of cis,cis and trans,trans isomers as well. The quality of the recent products is significantly improved and they contain only two CLA isomers: cis‐9,trans‐11 and trans‐10,cis‐12. CLA play apparently a key role in regulating body composition. Several studies showed a reduction in body fat mass and a slight increase in lean body mass depending on the species. A possible explanation for the decrease of body fat may be a stimulation of lipolysis and a reduction of lipoprotein lipase activity in adipocytes. In adipose and muscle tissue a CLA‐stimulated increase of carnitine palmitoyltransferase activity resulting in an enhanced fatty acid oxidation was shown. There is evidence that CLA provide protection against cytokine‐induced (Tumour necrosis factor‐α, interleukin‐1) skeletal‐muscle catabolism (anabolic effect). The body composition modulating effects are most impressive in rodents and seem to become smaller in pigs and in humans. Data on humans are insufficient. Further research is essential to characterize the multifunctionality of CLA in humans, in order to identify the specific physiological mechanism of the biologically active isomers and to determine the optimal level of these isomers for beneficial effects. 相似文献
14.
Effect of conjugated linoleic acid on body composition in mice 总被引:55,自引:7,他引:55
Yeonhwa Park Karen J. Albright Wei Liu Jayne M. Storkson Mark E. Cook Michael W. Pariza 《Lipids》1997,32(8):853-858
The effects of conjugated linoleic acid (CLA) on body composition were investigated. ICR mice were fed a control diet containing
5.5% corn oil or a CLA-supplemented diet (5.0% corn oil plus 0.5% CLA). Mice fed CLA-supplemented diet exhibited 57% and 60%
lower body fat and 5% and 14% increased lean body mass relative to controls (P<0.05). Total carnitine palmitoyltransferase activity was increased by dietary CLA supplementation in both fat pad and skeletal
muscle; the differences were significant for fat pad of fed mice and skeletal muscle of fasted mice. In cultured 3T3-L1 adipocytes
CLA treatment (1×10−4 M) significantly reduced heparin-releasable lipoprotein lipase activity (−66%) and the intracellular concentrations of triacylglyceride
(−8%) and glycerol (−15%), but significantly increased free glycerol in the culture medium (+22%) compared to control (P<0.05). The effects of CLA on body composition appear to be due in part to reduced fat deposition and increased lipolysis
in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes. 相似文献
15.
Sarah Laraichi Pilar Parra Rocío Zamanillo Ahmed El Amarti Andreu Palou Francisca Serra 《Lipids》2013,48(8):817-826
The scope of this study was to assess the impact of calcium and conjugated linoleic acid (CLA) supplementation on plasma fatty acid profiles and to evaluate potential synergistic effects of both compounds against dietary obesity. Mice separated into five experimental groups were followed: control (C), high-fat diet (HF), HF with calcium (Ca), HF plus CLA and HF with both Ca and CLA. Plasma metabolites and fatty acids were determined by commercial kits and gas chromatography, respectively. Both dietary calcium and CLA supplementation contributed to lower body fat gain under a HF diet. Maximum efficacy was seen with calcium; no additional effect was associated with the combined treatment with CLA. Plasma leptin, adiponectin and HOMA index were in accordance with an altered glucose/insulin homeostasis in the HF and HF + CLA groups, whereas control levels were attained under Ca-enriched diets. Plasma fatty acids showed minor changes associated to CLA treatment, but a high impact on PUFA was observed under Ca-enriched diets. Our results show that the mechanism underlying the anti-obesity effects of calcium supplementation is mediated mainly by changes in PUFA plasma profile. In addition, the lack of synergy on body weight reduction in combination with associated lipid profiles of calcium and CLA suggests that calcium may interfere with absorption and/or bioactivity of CLA, which can be of relevance when using CLA-fortified dairy products against human obesity. 相似文献
16.
The term “conjugated linoleic acid” (CLA) refers to a group of positional and geometric isomers that are derived from linoleic
acid and are found primarily in meat and milk products from ruminant animals. Due to the array of putative benefits associated
with various forms of CLA, there has been recent interest in supplementing human diets with these fatty acids especially when
weight loss is desired. However, in many animal models, CLA has been shown to decrease milk fat production. There is some
concern, therefore, that maternal CLA supplementation during lactation might inadvertently decrease nutrient supply to the
nursing infant. However, there is only limited research on the effect of CLA consumption on milk fat content in women. Based
on previously published work from our laboratory, we hypothesized that CLA supplementation would reduce the milk fat percentage
in lactating women in a dose-dependent manner. Breastfeeding women (n = 12) were assigned randomly to treatments of 4 g/day safflower oil (SFO), 2 g/day CLA plus 2 g/day SFO, or 4 g/day CLA in
a double blind, 3 × 3 Latin square design. Conjugated linoleic acid supplements contained approximately equal amounts of cis9,trans11–18:2 and trans10,cis12–18:2; the two most common isoforms of CLA. Milk was collected by complete breast expression on the last day (day 5) of
each intervention period and analyzed for macronutrient and fatty acid composition. On day 4 of each intervention period,
infant milk consumption was estimated by 24 h weighing of the infant. Washout periods were 9 days in length. We observed a
dose-dependent increase in the concentrations of cis9,trans11–18:2 and trans10,cis12–18:2 in the milk fat. However, we detected neither a change in overall macronutrient composition nor infant milk consumption.
These data do not support those obtained from animal models or our previous human work suggesting that consumption of CLA
mixtures necessarily reduces milk fat. It is possible that either (1) the interpretation of our previously published data
should be reevaluated, and/or (2) there are important intra- and inter-species differences in this regard. 相似文献
17.
Environmental Factors and Beta2‐Adrenergic Receptor Polymorphism: Influence on the Energy Expenditure and Nutritional Status of Obese Women
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Our aim was to evaluate the influence of the Gln27Glu polymorphism of the β2‐adrenergic receptor (ADRβ2) gene, fat intake and physical activity on the energy expenditure (EE) and nutritional status of obese women. Sixty obese women (30–46 years) participated in the study and were assigned to three groups depending on the genotypes: Gln27Gln, Gln27Glu and Glu27Glu. At baseline and after nutritional intervention, the anthropometric and body composition (bioelectrical impedance), dietary, EE (indirect calorimetry) and biochemical variables were measured. All women received a high‐fat test meal to determine the postprandial EE (short‐term) and an energy‐restricted diet for 10 weeks (long term). The frequencies of Gln27Gln, Gln27Glu and Glu27Glu were 36.67, 40.0 and 23.33 %, respectively. Anthropometric and biochemical variables and EE did not differ between groups, although women who had no polymorphism demonstrated decreased carbohydrate oxidation. On the other hand, the Glu27Glu genotype showed a positive relation with EE in physical activity and fat oxidation. The environmental factors and Gln27Glu polymorphism did not influence the nutritional status and EE of obese women, but physical activity in obese women with the polymorphism in the ADRβ2 gene can promote fat oxidation. The results suggest that encouraging the practice of physical exercise is important considering the high frequency of this polymorphism in obese subjects. 相似文献
18.
Julia Pappritz Peter Lebzien Ulrich Meyer Gerhard Jahreis Ronny Kramer Gerhard Flachowsky Sven Dänicke 《European Journal of Lipid Science and Technology》2011,113(12):1443-1455
The objective of the present study was to investigate the effects of a lipid‐encapsulated CLA preparation on rumen metabolism and the actual post‐ruminal bioavailability of the applied CLA isomers. In the rumen, the CLA supplementation modified the molar proportions of VFA. In period CLA‐1 the rumen fermentation shifted toward more butyric acid at the expense of acetic acid. The highest CLA supplementation resulted in increased amounts of isobutyric, isovaleric, and valeric acid. The apparent ruminal digestibility of starch increased in period CLA‐2. The ruminal protein degradation was higher after CLA supplementation, while the efficiency of the use of the RDP for microbial protein synthesis declined. The duodenal flow of trans‐10,cis‐12 CLA amounted to 16 and 5% of the intake in periods CLA‐1 and CLA‐2, respectively. The transfer of trans‐10,cis‐12 CLA from duodenum into milk was 36 and 48% in periods CLA‐1 and CLA‐2, respectively. Overall, the observed effects of the supplementation of lipid‐encapsulated CLA on the parameters of rumen metabolism were negligible. The actual low post‐ruminal bioavailability of trans‐10,cis‐12 CLA suggest that most of the applied fat supplement was biohydrogenated. 相似文献
19.
Despite extensive research on conjugated linoleic acid (CLA) showing multiple beneficial effects in animal models, little
is known about the role of dietary CLA in human health. To investigate if the beneficial effects of CLA seen in animal models
are relevant to humans, we conducted a study with 17 healthy female volunteers who lived in the Metabolic Research Unit of
the Western Human Nutrition Research Center for 93 d. This paper reports only the results from this study that are related
to the effects of CLA supplementation on blood coagulation, platelet function, and platelet fatty acid composition. Throughout
the study, the subjects were fed a low-fat diet (30 en% fat, 19 en% protein, and 51 en% carbohydrate) consisting of natural
foods with the recommended dietary allowances for all known nutrients. After a 30-d stabilization period, subjects were randomly
assigned to either an intervention group (n=10) whose diet was supplemented with 3.9 g/d of CLA or a control group (n=7) who received an equivalent amount of sunflower oil consisting of 72.6% linoleic acid with no detectable CLA. Platelet
aggregation was measured in platelet-rich plasma using adenosine diphosphate, collagen, and arachidonic acid agonists. No
statistical difference was detected between the amount of agonist required to produce 50% aggregation of platelet-rich plasma
before and after the subjects consumed the CLA, with the exception of a decrease in response to collagen. This decrease was
found in both control and intervention groups with no significant difference between the groups, suggesting that both linoleic
acid (sunflower oil) and CLA might have similar effects on platelet function. The prothrombin time, activated partial thromboplastin
time, and the antithrombin III levels in the subjects were determined. Again, there was no statistically significant difference
in these three parameters when pre-and post-CLA consumption values were compared. The in vivo bleeding times were also unaffected by CLA supplementation (10.4+2.8 min pre- and 10.2+1.6 min postconsumption). Platelet
fatty acid composition was not markedly influenced by the consumption of dietary CLA, although there was a small increase
in the amount of the 9 cis, 11 trans-18∶2 isomer normally present in platelets after feeding CLA for 63 days. In addition, small amounts of the 8 trans, 10 cis-18∶2 and the 10 trans, 12 cis-18∶2 isomers were detected in the platelets along with traces of some of the other isomers. Thus, when compared to sunflower 相似文献
20.
Roger E Adams Andie Hsueh Betty Alford Clay King Huanbiao Mo Robert Wildman 《Journal of the International Society of Sports Nutrition》2006,3(2):28-9
Conjugated linoleic acid (CLA) supplementation has shown convincing effects at reducing body fat in animals; yet human study
results have been somewhat inconclusive. The purpose of this study is to determine whether four weeks of CLA supplementation,
the approximate length of a commercial package, can result in a positive change in visceral adipose tissue in resistance-trained
middle-aged men. Thirty overweight and moderately obese, but otherwise healthy male subjects (aged 35 to 55 years) currently
involved in resistance training, were randomly assigned into CLA and placebo groups in a double-blind, placebo controlled
approach. The study lasted for 12 weeks and consisted of three four-week periods. During the first four weeks (run-in period)
each subject received placebo (4 g safflower oil). Throughout the next four weeks (supplementation period), the placebo group
continued receiving placebo, while the CLA group received 3.2 g/d of CLA. During the final four weeks (run-out period) all
subjects received the placebo. Computed tomography (CT) scans were used to measure visceral adipose tissue (VAT) at weeks
4, 8 and 12. No significant reduction in VAT cross-sectional area was determined in the CLA group during the study. On the
contrary, a significant reduction in cross-sectional area of VAT of 23.12 cm2 during the supplementation period was measured in the placebo group, which was abated during the run-out period. Our results
suggest that CLA supplementation of 3.2 g/d for four weeks does not promote decreases in VAT in middle-aged men currently
participating in a resistance-training program. 相似文献