Vitamin D Improves Oral Glucose Tolerance and Insulin Secretion in Human Diabetes

抄録

Glucose intolerance and impaired insulin secretion in vitamin D deficiency, and altered vitamin D metabolism in streptozotocin- or alloxan-induced diabetes, are well established in experimental animals. No such data are available in humans. The present study was conducted on a group of uncontrolled diabetic patients: those with non-insulin-dependent diabetes mellitus (NIDDM: 42) and those with insulin-dependent diabetes mellitus (IDDM: 6). After an initial oral glucose tolerance test, each subject was given one intramuscular injection of vitamin D (vitamin D₃: 300, 000IU), and the oral glucose tolerance test was then repeated after 4 weeks. Administration of vitamin D resulted in a significant improvement in the oral glucose tolerance, serum calcium, and also glucose-stimulated increase in serum insulin levels. Possible mechanism(s) of this beneficial effect of vitamin D on human diabetes is discussed.