What role does B12 play in Langlebigkeit?

Vitamin B12 (cobalamin) is crucial for DNA synthesis, nerve myelination, and homocysteine metabolism. Elevated homocysteine is a risk factor for cardiovascular disease and has been linked to accelerated aging, so optimal B12 status may indirectly support longevity. However, no robust clinical trials demonstrate that B12 supplementation directly extends lifespan in healthy individuals with normal levels. Evidence is primarily observational and mechanistic. Deficiency is more common in older adults and vegans, and should be assessed via blood biomarkers (holotranscobalamin, homocysteine). Consumer DNA tests (e.g., MyBody-X) may hint at methylation-related variants (like COMT) but do not replace lab testing. The evidence for B12's role in longevity is mechanistic/unclear, not human-strong. Safety note: excessive B12 is generally safe, but high-dose supplements are unnecessary without deficiency.