DNA Stoffwechseltest: which supplements make sense?

A DNA metabolism test can identify certain gene variants linked to nutrient processing (e.g., MTHFR, VDR, FTO). However, effect sizes are generally small, and the evidence base is mostly from GWAS, not randomized intervention trials. Supplements often recommended based on such tests (e.g., methylfolate, vitamin D, omega-3s) are commonly beneficial anyway, but the added value of genetic information is questionable. Without blood levels or medical guidance, supplementation carries risks (e.g., overdosing fat-soluble vitamins). The evidence for personalized supplement recommendations from DNA tests is weak to moderate. A possible exception is rare monogenic disorders, but these are usually not covered by consumer tests. Conclusion: DNA tests may offer hints, but they do not replace blood work and medical advice.