Composition/ Adipose Mass and Conjugated Linoleic Acid Effects.
Accumulating data demonstrate that consumption of conjugated linoleic acid (CLA) modulates body composition, especially by suppressing the accumulation of adipose tissue in mice, rats, pigs, and humans. For instance, mice fed CLA-supplemented diets exhibited over 50% lower body fat and approximately 10% increased lean body mass relative to those fed control diets. Further work demonstrated that dietary CLA-induced reduction of adiposity could be sustained in mice even after CLA was removed from the diet. Site specificity to CLA-mediated effects has also been shown across various depots of fat mass, specifically retroperitoneal and epididymal white adipose tissue masses and brown adipose tissue. Isomer-specific effects of CLA on adiposity have been observed, where t-10,c-12 CLA appears more effective in lowering adipose tissue mass than c-9,t-11 CLA isomer in mice. In addition, t-10,c-12 CLA is most able to modulate gene expression in cultured 3T3-L1 pre-adipocytes. In adult humans, the ability of CLA to reduce adipose tissue mass has been shown repeatedly. For instance, supplementation with CLA (3.4-6.8 g/day) for 12 wk resulted in reduction in fat depot mass, body weight and BMI. Mechanisms explaining how CLA reduces adiposity likely involves pathways that regulate energy expenditure including increased metabolic rates and decreased nocturnal respiratory quotients, mediated possibly through enhanced sympathetic nervous activity. Assuming safety of use, existing data point to a role for dietary CLA in maintenance of healthy body weight.