Risks and limits of Vitamin D Genetik

Vitamin D genetics involves variants in genes such as VDR, GC, CYP2R1, and DHCR7, which influence synthesis, transport, and receptor function. GWAS have identified significant but small effect sizes; heritability accounts for only about 20–30% of serum 25(OH)D variation. The majority is determined by sun exposure, diet, skin pigmentation, BMI, and lifestyle. Therefore, a genetic test alone cannot reliably predict or rule out vitamin D deficiency. Risks include overestimation of genetic influence: users with a 'risk genotype' might self-supplement with high doses, risking hypercalcemia. Conversely, a 'favorable' genotype could falsely reassure, masking actual insufficiency. Clinical guidelines (e.g., Endocrine Society) recommend serum 25(OH)D measurement as the gold standard – not genetics. Supplementation recommendations based solely on DNA tests lack evidence. MyBody-X explicitly states that its genetic insights are neutral hints, not medical evaluations. In summary, vitamin D genetics is scientifically intriguing but of limited practical value for individual dosing without a blood test. The risks of misinterpretation and over-supplementation are real.