What role does FADS1 play in fatigue?

The provided context does not contain direct evidence linking FADS1 to fatigue. FADS1 encodes a delta-5 desaturase involved in polyunsaturated fatty acid (omega-3/6) metabolism. Variants in FADS1 can alter the ratio of arachidonic acid to eicosapentaenoic acid (EPA), thereby modulating inflammatory pathways. Chronic low-grade inflammation is associated with fatigue, but no specific human studies from the context demonstrate a direct causal role of FADS1 polymorphisms in fatigue. The evidence is purely mechanistic and insufficient for clinical guidance. Lifestyle factors such as sleep, diet, stress, and physical activity are far more influential. A DNA test for FADS1 alone cannot explain or predict fatigue. Evidence grade: mechanistic/unclear.