Does early n.3 fatty acid exposure alter DNA methylation in the developing human immune system?

Abstract

Evaluation of: Lee HS, Barraza‑Villarreal A, Hernandez‑Vargas H et al. Modulation of DNA methylation states and infant immune system by dietary supplementation with n‑3 PUFA during pregnancy in an intervention study. Am. J. Clin. Nutr. 98(2), 480–487 (2013). Long-lasting effects of n-3 fatty acids on the immune cells involved in allergic disease may be due to epigenetic alterations. Pregnant women consumed the n-3 fatty acid docosahexaenoic acid (DHA; 400 mg/day) or placebo from mid-gestation until delivery, and the methylation status of CpG loci within the promoter regions of several genes involved in immune function was measured in umbilical cord blood mononuclear cells (CBMCs) using pyrosequencing. There was no significant effect of DHA supplementation in pregnancy on methylation within the promoter regions of any of the cytokine or transcription factor genes measured in CBMCs. Methylation of the promoter region of the genome stabilizer LINE-1 was higher in CBMCs from infants of mothers who smoked in the DHA group compared with those in the placebo group, although this effect was lost following statistical correction for confounders, but did not differ between nonsmoking women in the two groups. Several factors limit interpretation of the findings. It remains unknown whether there is a role for epigenetic alterations as a mechanism for long-lasting immune and clinical effects of very early n-3 fatty acid exposure.