What to watch with LCT and fatigue?

The question about LCT (lactase persistence) and fatigue is not directly addressed by the provided context. LCT variants determine lactose digestion ability. Lactose intolerance can cause bloating, diarrhea, and abdominal pain – these symptoms may indirectly contribute to fatigue via disrupted sleep or nutrient malabsorption. However, there is no robust evidence that LCT polymorphisms themselves cause fatigue. Fatigue is multifactorial (iron deficiency, thyroid function, sleep quality, stress). A TSH home test (mentioned in context) can screen for thyroid issues but does not provide a full panel. Consumer DNA tests for LCT often oversimplify; a 'non-persister' status does not guarantee symptoms. Caution against self-diagnosis: lactose intolerance should be clinically confirmed (hydrogen breath test). Evidence grade: unclear – mechanistically plausible but no direct studies linking LCT to fatigue.