Evidence check: MTHFR in the context of Langlebigkeit

Claims that MTHFR variants (e.g., C677T, rs1801133) directly influence longevity are weakly supported. MTHFR is a key enzyme in folate metabolism and affects homocysteine levels. Elevated homocysteine is a risk factor for cardiovascular disease, which can shorten lifespan. However, the effect of single MTHFR SNPs on homocysteine is small (~1–2 µmol/L) and highly dependent on folate intake. Population studies show no consistent association between MTHFR genotypes and all-cause mortality or extreme longevity. The evidence for a direct link to longevity is mixed: mechanistic and epidemiological hints exist, but no validated prediction models. Direct-to-consumer tests often overstate clinical relevance. Supplementing with methylfolate without medical indication is not recommended and may be harmful at high doses (e.g., masking B12 deficiency). For evidence-based longevity, lifestyle factors (diet, exercise, sleep) are far more important than individual MTHFR SNPs.