Myths vs facts: B12 and longevity

The claim that high B12 levels extend lifespan is a myth. B12 is essential for methylation, DNA synthesis, and neurological function, but excess does not confer additional longevity benefits. Observational studies link B12 deficiency – common in older adults due to malabsorption or in vegans – with cognitive decline and increased mortality. Correcting deficiency is crucial, but no robust evidence supports supraphysiological B12 supplementation for slowing aging. Genetic variants (e.g., MTHFR, FUT2) influence B12 status, but their effect on longevity is small and confounded by lifestyle. Evidence: human-moderate (observational). Caveat: B12 supplements are indicated for deficiency, not as anti-aging agents. MyBody-X tests can measure B12 levels but do not replace medical advice.