welche vitamine fehlen bei müdigkeit — can a DNA test help?

Fatigue can be caused by deficiencies in vitamin B12, vitamin D, iron, folate, or magnesium. A DNA test can identify genetic variants such as MTHFR (folate metabolism), VDR (vitamin D), or FUT2 (B12 absorption) that influence vitamin status. However, the effect sizes of these variants are small and not sufficient to diagnose a clinical deficiency. The gold standard for detecting vitamin deficiencies remains a blood test. DNA tests are not recommended as a standalone tool for supplementation decisions. Evidence is mixed: some SNPs have moderate human-observational support, but their predictive value for fatigue is weak. Caution: self-interpretation may lead to unnecessary or incorrect supplementation. Persistent fatigue should always be evaluated by a doctor with appropriate lab work.