Myths vs facts: DNA Stoffwechseltest and longevity

The claim that a DNA metabolism test can provide precise, clinically actionable dietary recommendations to extend lifespan is largely a myth. The facts: a few validated genetic variants (e.g., MCM6 for lactase persistence, CYP1A2 for caffeine metabolism, MTHFR C677T for folate metabolism) have reproducible but usually small effects on nutrient handling. Most commercial tests, however, sell markers with weak or absent evidence—such as those for 'optimal' macronutrient ratios or gluten sensitivity. The association between FADS1 variants (rs174546) and omega-3 needs, for example, is only detectable at the population level (GWAS, small effect) and is not clinically actionable alone. A blood test for actual omega-3 levels is more informative. Similarly, homocysteine is a moderate risk marker for cardiovascular disease; B-vitamins lower it, but whether this extends lifespan in healthy individuals is unproven. Longevity is multifactorial (epigenetics, lifestyle, environment)—a DNA test alone cannot provide a reliable 'longevity diet'. Marketing claims greatly overstate the evidence. Bottom line: these tests can offer interesting background information but not evidence-based life extension.