Maternal polymorphisms in the FADS1 and FADS2 genes modify the association between PUFA ingestion and plasma concentrations of omega-3 polyunsaturated fatty acids

•Our results suggest a possible gene-nutrient interaction in maternal plasma concentrations of n−3 PUFAS.•In pregnant women, increased dietary intake of ALA and LA/ALA ratio promoted plasma ALA accumulation in homozygotes for the minor alleles for polymorphisms rs174561 and rs3834458.•Moderate intake of LA/ALA ratio may reduce plasma concentration of EPA in pregnant women carrying the rs174575 minor allele. There is a lack of studies about polymorphisms in FADS genes in pregnant women. We aimed to verify the interaction between three FADS gene polymorphisms (rs174561; rs174575; rs3834458) and dietary α-linolenic acid (ALA) or linoleic/α-linolenic acid ratio (LA/ALA) and plasma concentrations of omega-3 (n−3) PUFAs in pregnant women. Of the 250 women evaluated, the homozygous for the rs174561 and rs3834458 minor allele had high plasma ALA concentrations at the highest ALA and LA/ALA ratio tertile (p