Effect of conjugated linoleic acid on body composition and plasma lipids in humans: an overview of the literature

Terpstra, A.H.M.

doi:10.1093/ajcn/79.3.352

Cited by 202 publications

(128 citation statements)

References 73 publications

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“…25 In humans, however, the majority of studies have shown that supplementation with CLA mixtures does not have an effect on plasma cholesterol or TG levels compared to controls. 5 Similarly, we found no difference between groups in the change in total cholesterol, LDL, HDL or TGs. We also assessed the effect of CLA on biomarkers of inflammation and endothelial dysfunction that have been linked to the development of cardiovascular disease: CRP, IL-6 and TNFR-2 are markers of systemic inflammation, whereas E-selectin, sICAM-1 and s-VCAM-1 are overexpressed in the presence of inflammatory stimuli to the endothelium.…”

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confidence: 44%

“…4 CLA's effect on body fat was first demonstrated almost a decade ago in mice, and research has since confirmed and extended these findings to include several species, with some variation by animal type and CLA isomer. 5 By far, the most dramatic results have been shown in mice with decreases in body fat between 40 and 80% compared to controls. 6 Proposed mechanisms have included increased fat mobilization and oxidation, reduced adipocyte proliferation and differentiation, and increased apoptosis in pre-adipocytes.…”

Section: Introductionmentioning

confidence: 99%

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The role of conjugated linoleic acid in reducing body fat and preventing holiday weight gain

et al. 2006

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Objective: The incidence of obesity and overweight in the US has increased considerably during the past two decades and currently affects 65% of the adult population. Research has indicated that small, yet irreversible, gains during the holiday season contribute to increases in weight during adulthood. Conjugated linoleic acid (CLA), a naturally occurring dietary fatty acid, has been found to reduce weight gain and dramatically decrease fat mass in animals. Although research in humans has shown inconsistent results, most studies have been of insufficient duration or have utilized body composition methods that are less accurate than the currently accepted criterion. Design: Randomized, double-blind, placebo-controlled study of 3.2 g/day CLA for 6 months. Subjects: Forty healthy, overweight subjects (age: 18-44 years; body mass index: 25-30 kg/m 2 ). Measurements: Body composition by the four-compartment model, resting metabolic rate (RMR) by indirect calorimetry, selfreported physical activity and dietary intake, and blood chemistries were determined at baseline and after 6 months. Body weight was measured monthly during the pre-holiday season (August-October), holiday season (November-December) and post-holiday season (January-March). Adverse events were assessed monthly. Results: Compared to CLA, the placebo group showed a greater rate of weight gain during the holiday season (P ¼ 0.01). Within the placebo group, holiday weight change was significantly greater compared to the pre-holiday period (August-October) (P ¼ 0.03). Six-month change in body composition was improved with CLA compared to placebo (P ¼ 0.02), and body fat was significantly reduced within the CLA group (À1.072.2 kg, P ¼ 0.05). CLA had no effect on RMR, physical activity or dietary intake. The rate of reported negative emotions decreased significantly with CLA, although there was no difference in any other category of adverse event. In comparison to the placebo, CLA did not affect insulin resistance, blood lipids and markers of liver function or markers of inflammation, with the exception of a significant decrease in a biomarker of endothelial dysfunction. Conclusion: CLA supplementation among overweight adults significantly reduced body fat over 6 months and prevented weight gain during the holiday season. Although no adverse effects were seen, additional studies should evaluate the effect of prolonged use of CLA.

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confidence: 44%

Section: Introductionmentioning

confidence: 99%

The role of conjugated linoleic acid in reducing body fat and preventing holiday weight gain

et al. 2006

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“…Published studies report contradicting results. Although in the majority of them there are no significant differences on body weight, body composition 26 or weight regain 27,28 between controls and CLA-supplemented groups, some studies suggest that CLA might have a tendency to increase lean body mass 27,29,30 . On one hand, one study carried out in overweight/obese adult volunteers 30 report a reduction in body fat mass with doses $3.4 g MI-CLA per day at week 12 (150-580 g more than placebo), with a significant increase in body lean mass in the group that received 6.8 g MI-CLA per day, measured by dual-energy X-ray absorptiometry; however, this group was also the only one with a significant increase in exercise level.…”

Section: Evidence Of Conjugated Linoleic Acid Effects On Body Weight mentioning

confidence: 99%

Conjugated linoleic acid (CLA) and obesity

Silveira

Carraro

Monereo

et al. 2007

Public Health Nutr.

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Background: The term conjugated linoleic acid (CLA) refers to several positional and geometric conjugated dienoic isomers of linoleic acid (LA), of which the trans-10,cis-12 isomer has been reported to reduce adiposity and increase lean mass in mice and other animals when included at #1% of the diet. However, most dietary CLA in humans is obtained from dairy products, accounting for the cis-9,trans-11 CLA isomer, also known as rumenic acid, for more than 90% of the total CLA intake. Commercial CLA preparations industrially produced, containing trans-10,cis-12 and cis-9,trans-11 CLA isomers in diverse proportions, are attracting consumers' interest because of the purported body fat-lowering effects of CLA, coupled to the perception of a 'natural' compound devoid of harmful effects. Nevertheless, despite numerous studies on CLA effects on body composition for nearly a decade, the mechanisms by which CLA isomers elicit their effects remain largely unknown. The purpose of this paper is to provide an updated review of the studies performed on animals and humans, as well as to describe the potential mechanisms involved in CLA effects on body weight and composition and metabolism. Method: Literature review. Results: Experiments in humans have not been able to show a significant effect on body weight, body composition or weight regain related to either of the CLA isomers. In fact, some studies suggest a tendency towards a decrease in body fat mass and an increase in body lean mass, while some others raise concern about the possibility of deleterious effects of trans-10,cis-12 CLA on lipid profile, glucose metabolism and insulin sensitivity. Conclusions: Evidence regarding effectiveness of CLA in humans is not concluding.

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“…Today a number of beneficial physiological properties are attributed to CLA such as anti-cancer, anti-atherosclerosis, anti-inflammatory, and anti-obesity effects (reviewed in Scimeca 1999;Gnädig et al 2001;Pariza et al 2001;Evans ME et al 2002;Belury 2002;Terpstra 2004;Wahle et al 2004;Zulet et al 2005; Kelley et al 2007;Li et al 2008). These beneficial effects seem to be structure-specific.…”

Section: Introductionmentioning

confidence: 99%

Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α‐Tocopherol: The Hydroperoxide Pathway

Pajunen

Johansson

Hase

et al. 2008

Lipids

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The autoxidation of conjugated linoleic acid (CLA) is poorly understood in spite of increasing interest in the beneficial biological properties of CLA and growing consumption of CLA-rich foods. In this thesis, the autoxidation reactions of the two major CLA isomers, 9-cis,11-transoctadecadienoic acid and 10-trans,12-cis-octadecadienoic acid, are investigated. The results contribute to an understanding of the early stages of the autoxidation of CLA methyl ester, and provide for the first time a means of producing and separating intact CLA methyl ester hydroperoxides as well as basic knowledge on lipid hydroperoxides and their hydroxy derivatives.Conjugated diene allylic monohydroperoxides were discovered as primary autoxidation products formed during autoxidation of CLA methyl esters in the presence and absence oftocopherol. This established that one of the autoxidation pathways of CLA methyl ester is the hydroperoxide pathway.Hydroperoxides were produced from the two major CLA methyl esters by taking advantage of the effect of -tocopherol to promote hydroperoxide formation. The hydroperoxides were analysed and separated first as methyl hydroxyoctadecadienoates and then as intact hydroperoxides by HPLC. The isolated products were characterized by UV, GC-MS, and NMR techniques. In the presence of a high amount of -tocopherol, the autoxidation of CLA methyl ester yields six kinetically-controlled conjugated diene monohydroperoxides and is diastereoselective in favour of one particular geometric isomer as a pair of enantiomers. The primary autoxidation products produced from the two major CLA isomers include new positional isomers of conjugated diene monohydroperoxides, the 8-, 10-, 12-, and 14-hydroperoxyoctadecadienoates. Furthermore, two of these new positional isomers have an unusual structure for a cis,trans lipid hydroperoxide where the allylic methine carbon is adjacent to the cis instead of the usual trans double bond.The 1 H and 13 C NMR spectra of nine isomeric methyl hydroxyoctadecadienoates and of ten isomeric methyl hydroperoxyoctadecadienoates including the unusual cis,trans hydroperoxides, i.e. Me 8-OOH-9c,11t and Me 14-OOH-10t,12c, were fully assigned with the aid of 2D NMR spectroscopy. The assigned NMR data enabled determination of the effects of the hydroxyl and hydroperoxyl groups on the carbon chemical shifts of CLA isomers, identification of diagnostic signals, and determination of chemical shift differences of the olefinic resonances that may help with the assignment of structure to as yet unknown lipid hydroperoxides either as hydroxy derivatives or as intact hydroperoxides.A mechanism for the hydroperoxide pathway of CLA autoxidation in the presence of a high amount of -tocopherol was proposed based on the characterized primary products, their relative distribution, and theoretical calculations. This is an important step forward in CLA research, where exact mechanisms for the autoxidation of CLA have not been presented before. Knowledge of these hydroperoxide formation steps is of cr...

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Effect of conjugated linoleic acid on body composition and plasma lipids in humans: an overview of the literature

Cited by 202 publications

References 73 publications

The role of conjugated linoleic acid in reducing body fat and preventing holiday weight gain

The role of conjugated linoleic acid in reducing body fat and preventing holiday weight gain

Conjugated linoleic acid (CLA) and obesity

Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α‐Tocopherol: The Hydroperoxide Pathway

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