What role does Homocystein play in Langlebigkeit?

Homocysteine is a sulfur-containing amino acid whose elevated levels (hyperhomocysteinemia) are associated with increased risk of cardiovascular disease, cognitive decline, and all-cause mortality, thus potentially impacting longevity. Observational studies link high homocysteine to shorter telomeres and oxidative stress, mechanisms of aging. However, randomized controlled trials of B-vitamin supplementation (folic acid, B12, B6) to lower homocysteine have not consistently reduced cardiovascular events or mortality, suggesting homocysteine may be a marker rather than a causal factor. The role in longevity is therefore indirect and context-dependent. Genetic variants like MTHFR C677T can raise homocysteine, but even then, standard folate is effective. Routine testing is not recommended for the general population. For longevity, maintaining adequate B-vitamin status is prudent, but aggressive lowering of homocysteine beyond normal ranges lacks evidence for extending lifespan. Evidence is mixed: strong association but weak causal intervention data.