Lay opinion vs evidence: MTHFR Senioren

Lay opinion often claims that MTHFR variants (especially C677T) in seniors inevitably cause elevated homocysteine, cardiovascular disease, and cognitive decline, requiring high-dose methylfolate. The evidence is more nuanced: MTHFR polymorphisms are common (10–15% of Europeans are homozygous) and reduce enzyme activity, but most individuals with adequate folate intake maintain normal homocysteine levels. In seniors, elevated homocysteine is indeed a risk factor for cardiovascular events and dementia, but the causal contribution of MTHFR genotype is modest – other factors like vitamin B12, B6, folate status, kidney function, and lifestyle are more influential. Randomized trials of homocysteine-lowering B vitamin therapy have not shown consistent benefit for cardiovascular outcomes. Guidelines recommend a general folate intake of 400–800 µg/day for seniors, regardless of MTHFR status. Specific supplementation based solely on genotype is not well-supported. Lay opinion overstates the clinical relevance of MTHFR in seniors.