Evidence check: B12 in the context of Langlebigkeit

The provided context does not contain specific information on vitamin B12 and longevity. In general, B12 is essential for nerve function and red blood cell formation; deficiency is linked to cognitive decline and increased homocysteine, a cardiovascular risk factor. However, observational studies have also reported that very high B12 levels (from supplements) may be associated with slightly higher all-cause mortality, though causality is unproven. For healthy individuals without deficiency risk (e.g., vegans, older adults), routine high-dose B12 supplementation is unlikely to extend lifespan. Evidence is mixed: strong for preventing deficiency, weak for longevity enhancement. Caveat: Do not assume more B12 equals longer life.