Evidence check: FADS1 in the context of Fruchtbarkeit

FADS1 encodes delta-5 and delta-6 desaturases, key enzymes in polyunsaturated fatty acid (PUFA) metabolism, particularly the conversion of alpha-linolenic acid (ALA) to EPA and DHA. Omega-3 fatty acids are important for fertility: they support sperm quality, oocyte maturation, and embryonic development. Several GWAS have linked FADS1 variants to altered blood PUFA levels. However, direct evidence for a causal effect on human fertility is limited. No randomized controlled trials have tested whether specific FADS1 genotypes influence fertility outcomes. Most data come from mechanistic studies or associations with fatty acid profiles. Therefore, personalized dietary advice based solely on FADS1 genotype to enhance fertility is not evidence-based. While optimizing omega-3 intake is generally beneficial, the genetic contribution is modest and interacts with diet, lifestyle, and other factors. Consumers should be cautious of marketing claims that overstate the role of FADS1 in fertility. The evidence level is best described as 'GWAS/mechanistic' with weak direct support for fertility endpoints.