welche mikronährstoffe sollte man testen lassen — what are common causes?

Which micronutrients to test depends on individual risk factors, symptoms, and diet. Routine broad panels are not recommended by most guidelines because they often yield false positives or irrelevant results. Common evidence-based candidates include vitamin D (if sun exposure is low), vitamin B12 (vegans, GI disorders, post-bariatric surgery), iron/ferritin (blood loss, fatigue), folate (pregnancy planning, alcohol use), and selenium or zinc (specific diets, chronic inflammation). The EFSA set upper intake levels (ULs) in 2023/2024: vitamin E at 300 mg/day and selenium at 255 µg/day. High-dose supplements exceeding these levels (e.g., ≥400 IU vitamin E) have been linked to increased mortality and prostate cancer risk in RCTs (SELECT, Miller meta-analysis). Direct-to-consumer DNA tests claiming ‘deficiency genes’ (e.g., SOD2, FUT2) are based on weak mechanistic evidence and are not clinically actionable. Therefore, the evidence for routine micronutrient testing is mixed: useful in at-risk groups, but not as a general health screen. Safety note: high doses of fat-soluble vitamins and trace minerals can be toxic; always consult a physician before supplementing.