Myths vs facts: FADS1 and Blutzucker

FADS1 encodes delta-5 desaturase, a key enzyme in polyunsaturated fatty acid (PUFA) metabolism. GWAS and candidate gene studies have linked certain FADS1 variants (e.g., rs174550) to altered blood glucose levels and type 2 diabetes risk. The proposed mechanism involves changes in omega-3/omega-6 fatty acid ratios, which can modulate insulin sensitivity. However, the evidence is inconsistent: some studies report significant associations, while others find weak or no effects. Effect sizes are generally small and depend on ethnicity, diet, and other genetic factors. Thus, FADS1 is a potential but unconfirmed biomarker. No clinical guidelines currently recommend DNA testing for FADS1 variants to predict or manage blood glucose. The evidence is primarily mechanistic and from GWAS, not from randomized controlled trials. Consumers should be cautious of exaggerated claims that a specific diet (e.g., high omega-3) based on FADS1 genotype will significantly improve blood sugar. Dietary changes should follow established evidence-based principles.