What role does VDR play in Schlaf?

The vitamin D receptor (VDR) is a nuclear receptor activated by calcitriol, the active form of vitamin D, and regulates genes involved in circadian rhythm and melatonin synthesis. Several studies have linked VDR polymorphisms (e.g., FokI, BsmI, TaqI) to sleep traits such as duration, latency, and quality. However, the evidence is moderate and inconsistent: some associations have been replicated in GWAS, but large-scale clinical trials confirming causality are lacking. Moreover, the effect of VDR variants is often modulated by actual vitamin D status – low serum vitamin D is more strongly associated with sleep disturbances than genetics alone. Consumer DNA tests that include VDR markers cannot diagnose sleep disorders. Interpretation should consider lifestyle factors (sun exposure, diet) and measured vitamin D levels. Vitamin D deficiency may contribute to fatigue and poor sleep, but supplementation without medical advice is not recommended. Overall, VDR plays a supportive but non-deterministic role in sleep regulation.