What should I know about test auf unvertraglichkeiten?

Tests for intolerances (e.g., lactose, fructose, gluten) are often marketed as DNA tests or home kits. Scientific backing is generally weak. A few well-established genetic intolerances (e.g., lactose intolerance, rs4988235) have solid evidence. Most other 'intolerance tests' rely on SNPs with small effect sizes or purely mechanistic hypotheses – the evidence is mostly 'marketing'. A direct-to-consumer test like MyBody-X DNA Nutrition Test may offer hints but cannot replace medical diagnosis. Symptoms such as bloating, diarrhea, or skin reactions have many causes (gut microbiome, stress, diet). Without a controlled elimination diet and clinical tests (e.g., hydrogen breath test), the predictive value of a genetic test is limited. Be cautious of exaggerated claims: most intolerances are multifactorial and not solely genetically determined.