Effets des acides gras conjugués sur les composantes de la dépense énergétique chez la souris et le hamster

We measured the effects of feeding conjugated linoleic acids (CLA) on the various components of energy expenditure in two species known to react differently to CLA treatments, the hamster and the mouse. We measured in particular resting energy expenditure, and the metabolic responses to feeding and treadmill exercise. Our results confirmed the poor responsivenes of hamsters and the high sensibility of mice. In agreement with the lack of effects of CLAs on body weight and body composition in hamsters, we did not find any significant effects on the various components of energy expenditure. Mice responded to CLA feeding by a complete inhibition in the development of the white adipose tissue, but we observed only marginal effects of the components of energy expenditure, and it was difficult to separate the metabolic alterations that resulted from the energy deficit and those that could be specifically attributed to CLAs feeding. However, the possibility that a high spontaneous activity together with the progressive development of a form of insulin resistance participate in the lipoatrophy observed in mice

Effet anti-obésité des CLA : mythe ou réalité ?

Conjugated linoleic acids (CLA) are positional and geometric isomers of linoleic acid. Inclusion of CLA in the diet provokes a rapid and marked decrease in body weight gain and adiposity in mice leading to a lipoatrophic syndrome. However, CLA supplementation raised fasting blood glucose and insulin concentrations and was associated with severe insulin resistance and liversteatosis. Conflicting results have been reported with regard to reduction of fat mass in humans. We have reviewed the publish literature regarding the effect of CLA on body composition in humans and animal models. These studies indicate that t10-c12 was the isomer that reduced adipose fat storage, however it also increased insulin resistance and liver steatosis. Although significant benefit to humans from dietary CLA supplementation is questionable, it may create several health risks in both animals and humans. The potential mechanisms by which CLA inhibits lipid storage capacity in adipocytes are presented and discussed in this review