What role does VDR play in blood sugar?

The vitamin D receptor (VDR) is a nuclear receptor activated by calcitriol, the active form of vitamin D. It regulates genes involved in insulin secretion, insulin sensitivity, and glucose metabolism. Several VDR polymorphisms (e.g., rs2228570, rs1544410) have been associated with type 2 diabetes risk and impaired insulin release in GWAS and meta-analyses, but effect sizes are modest. Lifestyle factors and actual vitamin D status are stronger determinants. A DNA test for VDR variants alone cannot predict or manage blood sugar; it should be combined with clinical markers (fasting glucose, HbA1c, 25(OH)D). Evidence: human-moderate. Caveat: do not supplement vitamin D based solely on genetics; get a blood test first.