CLA, Omega-3s Don't Support Insulin Resistance

PADOVA, ItalyThe results of a recent Italian study did not support beneficial effects of conjugated linoleic acid (CLA)/omega-3 long-chain polyunsaturated fatty acids (omega-3 LC-PUFAs) for beta-cell dysfunction or insulin resistance in humans, but suggested insulin sensitivity in older obese subjects is reduced (Eu J Clin Nutr. 2009;63:77886) (DOI:10.1038/ejcn.2008.45). CLA (3 g/d) plus omega-3 LC-PUFA (3 g/d) or a control oil (6 g/d) was given to lean (n=12; BMI 2026 kg/m2) or obese (n=10; BMI 2935 kg/m2) young (20 to 37 years old) or lean (n=16) or obese (n=11) older men (5065 years) for 12 weeks. The study had a double blind, placebo-controlled randomized crossover design, and primary end points were insulin secretion and sensitivity during a standardized meal test, evaluated by modeling glucose, insulin and C-peptide data.
The combination was well tolerated. There was no significant difference in fasting levels of glucose, insulin or C-peptide after CLA/omega-3 LC-PUFA treatment compared with control oil. Neither insulin secretion nor estimated sensitivity was affected by CLA/omega-3 LC-PUFA in lean or obese young subjects or in older lean subjects. However, in older obese subjects, estimated insulin sensitivity was reduced with CLA/omega-3 LC-PUFA compared with control (P=0.024).