Antiobesity mechanisms of action of conjugated linoleic acid.

Department of Nutrition, University of North Carolina Greensboro, PO Box 26170, Greensboro, NC 27402-6170, USA.
The Journal of nutritional biochemistry (Impact Factor: 4.29). 11/2009; 21(3):171-9. DOI: 10.1016/j.jnutbio.2009.08.003
Source: PubMed

ABSTRACT Conjugated linoleic acid (CLA), a family of fatty acids found in beef, dairy foods and dietary supplements, reduces adiposity in several animal models of obesity and some human studies. However, the isomer-specific antiobesity mechanisms of action of CLA are unclear, and its use in humans is controversial. This review will summarize in vivo and in vitro findings from the literature regarding potential mechanisms by which CLA reduces adiposity, including its impact on (a) energy metabolism, (b) adipogenesis, (c) inflammation, (d) lipid metabolism and (e) apoptosis.

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    ABSTRACT: BACKGROUND AND OBJECTIVE: Metabolic syndrome (MS) frequency is growing and diet has an important influence on its evolution. Our objective was to study the effect of 3 sources of polyunsaturated fatty acids on MS parameters in humans. PATIENTS AND METHOD: The MS was diagnosed according to the International Diabetes Federation. Three groups of individuals (n=15/group) were quasi-randomly assigned to one of the following treatments during 6 weeks: a) 1.8g/d n-3 (1.08g eicosapentoaenoic acid+0.72g docosahexaenoic acid); b) 2.0g/d conjugated linoleic acid (CLA, 50:50, cis9:trans11, trans10:cis12), and c) 40g/d walnut. The clinical and biochemical parameters were evaluated at the beginning and the end of the essay. RESULTS: In the group with n-3 the triglycerides level decreased from 183.9±35.2mg/dl to 149.6±29.0mg/dl (P=.007). In the group with walnut the HDL level rose from 41.7±5.2mg/dl to 47.8±5.4mg/dl (P=.004) and the Castelli index (total cholesterol/HDL) decreased from 4.86±0.97 to 3.82±0.81 (P=.004). There were not significant changes in the CLA group. At the end of the essay, 46.7% of walnut group patients, 46.7% of n-3 group and 20% of CLA group, had no MS. CONCLUSIONS: The groups that consumed polyunsaturated fatty acids n-3 and those in walnut in moderate daily doses during 6 weeks had an improvement of the dyslipidemia component of MS, hypertriglyceridemia and low HDL level.
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    ABSTRACT: μ-Calpain is a calcium-dependent cysteine protease, which is activated by μM concentration of calcium in vitro. Disrupted intracellular calcium homeostasis leads to hyper-activation of μ-calpain. Hyper-activated μ-calpain enhances the accumulation of β-amyloid peptide by increasing the expression level of β-secretase (BACE1) and induces hyper-phosphorylation of tau along with the formation of neurofibrillary tangle by mediating p35 cleavage into p25, both of which are the major mechanisms of neurodegeneration in Alzheimer's disease (AD). Hence, inhibition of μ-calpain activity is very important in the treatment and prevention of AD. In this study, conjugated linoleic acid (CLA), an eighteen-carbon unsaturated fatty acid, was discovered as a μ-calpain-specific inhibitor. CLA showed neuroprotective effects against neurotoxins such as H(2)O(2) and Aβ(1-42) in SH-SY5Y cells, and inhibited Aβ oligomerization/fibrillation and Aβ-induced Zona Occludens-1 degradation. In addition, CLA decreased the levels of proapoptotic proteins, p35 conversion to p25 and tau phosphorylation. These findings implicate CLA as a new core structure for selective μ-calpain inhibitors with neuroprotective effects. CLA should be further evaluated for its potential use as an AD therapeutic agent.
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    ABSTRACT: Previous studies have shown that adding fish oil (FO) to ruminant animal diets increased vaccenic acid (VA; t11 C18:1) accumulation in the rumen. Therefore, the objective of this study was to evaluate the effect of dietary FO amounts on selected strains of rumen bacteria involved in biohydrogenation. A single-flow continuous culture system consisting of four fermenters was used in a 4 × 4 Latin square design with four 9 days consecutive periods. Treatment diets were as follows: (i) control diet (53:47 forage to concentrate; CON), (ii) control plus FO at 0.5% (DM basis; FOL), (iii) control plus FO at 2% (DM basis; FOM) and (iv) control plus FO at 3.5% (DM basis; FOH). Fermenters were fed treatment diets three times daily at 120 g/day. Samples were collected from each fermenter on day 9 of each period at 1.5, 3 and 6 h post-morning feeding and then composited into one sample per fermenter. Increasing dietary FO amounts resulted in a linear decrease in acetate and isobutyrate concentrations and a linear decrease in acetate-to-propionate ratio. Propionate, butyrate, valerate and isovalerate concentrations were not affected by FO supplementation. Concentrations of C18:0 in fermenters linearly decreased, while concentrations of t10 C18:1 and VA linearly increased as dietary FO amounts increased. The concentrations of c9t11 and t10c12 conjugated linoleic acid were not affected by FO supplementation. The DNA abundance for Butyrivibrio fibrisolvens, Butyrivibrio vaccenic acid subgroup, Butyrivibrio stearic acid subgroup and Butyrivibrio proteoclasticus linearly decreased as dietary FO amounts increased. In conclusion, FO effects on trans fatty acid accumulation in the rumen may be explained in part by FO influence on Butyrivibrio group.
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May 31, 2014

Arion Kennedy