Docosahexaenoic Acid and Eicosapentaenoic Acid Intakes Modulate the Association of FADS2 Gene Polymorphism rs526126 with Plasma Free Docosahexaenoic Acid Levels in Overweight Children

Polyunsaturated fatty acids are involved in a wide variety of biological functions. Linoleic acid and alpha-linolenic acid are two essential fatty acids that the body cannot synthesize. The conversion rates in the body depend on FADS2 genetic variants. Certain variations in this gene are directly responsible for the low levels and poor conversion efficiency of the delta-6 desaturase enzyme, resulting in low circulating levels of docosahexaenoic acid. In this study, we evaluated the impact of the rs526126 FADS2 gene polymorphism on fatty acid levels in a group of two hundred children (n = 95 males, n = 105 females) aged 7-18 years, with obesity defined by BMI > +2 SD. Fatty acid quantification was performed by LC-MS/MS while genotyping for genetic variants was performed using a custom-made hotspot sequencing panel of 55 SNPs. Our results suggest that rs526126 FADS2 gene polymorphism specifically impacts the plasma levels of free n-3 polyunsaturated fatty acids. Finally, the presence of the minor allele G of rs526126 could have beneficial effects, as it was associated with higher levels of free docosahexaenoic acid in plasma, especially in children with low n-3 intakes.