This study aims to assess methylation modifications in blood cell genes induced by eicosapentaenoic acid (EPA) and/or alpha-lipoic acid (LA) supplementation, and their potential relationship with metabolic risk biomarkers. Healthy overweight/obese women were assigned to 4 experimental groups (control or groups supplemented with 1.3 g EPA/day, 0.3 g LA/day, or both), all followed a 10-week hypocaloric diet. White blood cells DNA was hybridized in Human-450K-methylation microarray. Differentially methylated CpGs (post-pre) were identified in supplemented groups, including CpG regions from NCK2, FITM2, TRRAP, RPTOR and CREBBP genes. In peripheral blood mononuclear cells (PBMC), LA upregulated NCK2, TRRAP and RPTOR mRNA, which negatively associated with changes in body weight and fat mass. Changes in cg10320884 (TRRAP) methylation site negatively correlated with changes in TRRAP mRNA in PBMC, and positively with Framingham score. Further studies are needed to better characterize the potential involvement of epigenetics in the actions of LA and EPA. (C) 2017 Elsevier Ltd. All rights reserved.