How are LCT and Langlebigkeit related?

The relationship between LCT (lactase persistence) and longevity is not well established. LCT variants determine adult lactose digestion, a trait that evolved in dairying populations. Some observational studies (e.g., in Sardinia or Scandinavia) have reported associations between lactase persistence and increased lifespan, but effect sizes are small and confounded by diet, lifestyle, and population stratification. No randomized controlled trials exist to support a causal link. Longevity is polygenic and multifactorial; a single gene like LCT does not directly determine lifespan. Consumers should not interpret a lactase persistence genotype as a longevity marker. Evidence grade: unclear – current literature is mostly associative and not consistently replicated. Sources: none from the provided context.