Docosahexaenoic Acid-Rich Fish Oil Supplementation Improves Body Composition without Influence of the PPARγ Pro12Ala Polymorphism in Patients with Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Background: The aims of this research were to investigate (1) the impact of docosahexaenoic acid (DHA)-rich fish oil supplementation on body composition, plasma adiponectin level, and peroxisome proliferator-activated receptor γ (PPARγ) gene expression, and (2) whether the effect of DHA-rich fish oil supplementation on the aforementioned variables is modulated by PPARγ Pro12Ala polymorphism. Methods: We genotyped PPARγ Pro12Ala polymorphism in subjects with type 2 diabetes mellitus (T2DM). Ala carriers and non-Ala carriers were randomly assigned to DHA-rich fish oil or placebo intake for 8 weeks. Results: Glycemic control was not affected by the intervention. The supplementation with DHA-rich fish oil decreased waist circumference (p < 0.001), body fat mass (p = 0.01), body fat percent (p = 0.04), and visceral fat rating (p = 0.02) as well as trunk fat mass (p = 0.04). Weight, body mass index, fat-free mass, adiponectin level, and PPARγ gene expression changes showed no significant difference. No gene-diet interaction was found on body composition, adiponectin level, and PPARγ gene expression. Conclusions: DHA-rich fish oil supplementation favorably modulated body composition in patients with T2DM and could be useful to reduce visceral obesity. However, the PPARγ Pro12Ala polymorphism did not influence the changes in the desired variables.