FADS genotype affects change in fatty acid levels after a Mediterranean dietary intervention

Abstract

A Mediterranean diet increases intake of n‐3 and n‐9 fatty acids and lowers intake of n‐6 fatty acids. Limiting n‐6 fatty acid levels is expected to decrease levels of pro‐inflammatory eicosanoids such as prostaglandin E2 (PGE2) that increase colon cancer risk. This study evaluated whether polymorphisms in fatty acid desaturases (FADS1 and FADS2) genes may identify subgroups that have a greater response to dietary changes. A total of 107 individuals with a personal history of adenomas or colon cancer were randomized to either a Mediterranean diet or a Healthy diet. Fatty acids were measured in both serum and colonic mucosa at baseline and at 6 months. Each individual was genotyped for 4 SNPs in the FADS1/FADS2 cluster. Genetic variation in the FADS cluster was strongly associated with baseline serum arachidonic acid (p<0.0001) but less evidence was present for serum and colonic mucosa n3 fatty acids. Minor allele carriers had lower 20:4, n6 levels at baseline than major allele carriers. Both diets led to slightly but not significantly lower 20:4, n6 levels at 6 months. The Mediterranean diet intervention increased long chain n3 fatty acids in the colonic mucosa. There was a significant interaction of diet and FADS genotype on changes in fatty acid levels after intervention indicating that a Mediterranean intervention may have a relatively larger impact in specific subgroups.