Myths vs facts: LCT and Langlebigkeit

The myth that the LCT gene (lactase persistence) directly influences longevity is not supported by robust evidence. Genetics primarily determines whether an individual can digest lactose in adulthood – a trait evolutionarily selected in dairy-farming populations. GWAS studies (e.g., rs4988235) show strong association with lactose tolerance, but no causal link to lifespan. The idea that dairy consumption, guided by LCT genotype, significantly extends or shortens life is an oversimplification. Longevity is polygenic and heavily modulated by lifestyle, diet, and environment. Observational studies show mixed results: some suggest modest benefits of dairy for bone health, others point to risks (e.g., prostate cancer). The evidence is heterogeneous and cannot be reduced to a single gene variant. Conclusion: LCT testing is valid for lactose intolerance, but not for longevity predictions. Consumers should avoid drastic dietary changes based solely on this gene.