What to watch with FADS1 and fertility?

FADS1 encodes delta-5 desaturase, a key enzyme in polyunsaturated fatty acid (PUFA) metabolism. Variants such as rs174547 alter the conversion of alpha-linolenic acid (ALA) to EPA/DHA and linoleic acid to arachidonic acid. These fatty acids are precursors for prostaglandins and leukotrienes, which modulate inflammation and hormone synthesis (e.g., estrogen, progesterone). Imbalanced PUFA profiles can affect oocyte quality, sperm function, and implantation. Evidence is primarily mechanistic and from GWAS; direct RCTs linking FADS1 variants to fertility outcomes are lacking. Effect size is moderate and modifiable by diet (e.g., omega-3 supplementation). Caveat: FADS1 is one piece of a complex puzzle; lifestyle, age, and other genetic factors dominate. No standalone clinical recommendation without professional guidance.