DNA Methylation Pattern in Overweight Women under an Energy-Restricted Diet Supplemented with Fish Oil

Abstract

Dietary factors modulate gene expression and are able to alter epigenetic signatures in peripheral blood mononuclear cells (PBMC). However, there are limited studies about the effects of omega-3 polyunsaturated fatty acids (n-3 PUFA) on the epigenetic mechanisms that regulate gene expression. This research investigates the effects ofn-3-rich fish oil supplementation on DNA methylation profile of several genes whose expression has been reported to be downregulated byn-3 PUFA in PBMC:CD36,FFAR3,CD14,PDK4, andFADS1. Young overweight women were supplemented with fish oil or control in a randomized 8-week intervention trial following a balanced diet with 30% energy restriction. Fatty acid receptorCD36decreased DNA methylation at CpG +477 due to energy restriction. Hypocaloric diet-induced weight loss also reduced the methylation percentages of CpG sites located inCD14,PDK4, andFADS1. The methylation patterns of these genes were only slightly affected by the fish oil supplementation, being the most relevant to the attenuation of the weight loss-induced decrease inCD36methylation after adjusting by baseline body weight. These results suggest that then-3 PUFA-induced changes in the expression of these genes in PBMC are not mediated by DNA methylation, although other epigenetic mechanisms cannot be discarded.