In a 2007 review of the research, researchers noted that vitamin D and calcium work hand in hand to influence the body's secretion of insulin, the hormone that controls blood sugar levels.
In one study of 314 healthy adults, vitamin D appears to have offset or prevented age-related increase in blood glucose levels. In the control group, participants averaged a 6.1 mg/dl increase in fasting blood sugar over three years. However, people taking vitamin D (700 IU daily) and calcium (500 mg daily) supplements had virtually no change in their fasting blood sugar levels, according to the 2007 report in Diabetes Care.
Early in 2009, doctors at the Harvard School of Public Health found that low vitamin D and calcium levels were related to higher, unhealthy levels of C-peptide, a common marker of insulin function. A separate study by researchers at the University of California, Los Angeles, found that people with low vitamin D levels were more likely to have insulin resistance (a form of prediabetes) and also abnormalities in beta cells, which make insulin in the pancreas.
In 2008 Australian researchers reported on their use of vitamin D in the treatment of 51 patients with type 2 diabetes who had nerve problems, including numbness, tingling, and burning. After taking an average of 2,000 IU daily for three months, pain decreased by roughly half.
Call Your Doc
None of this means you should start treating yourself with a high dose of vitamin D. However, it's probably worthwhile having your vitamin D and calcium blood levels tested and discussing with your doctor the possibility of taking supplements and an appropriate dosage for you. We live in the age of the proactive healthcare consumer: Call your doctor's office and get the answers you need.
Note: Before changing or adding any nutritional supplement to your regimen, talk to your health care provider.
Reviewed by Susan Weiner, R.D., M.S., C.D.E., C.D.N. 10/10
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- Pittas AG, SS Harris, PC Stark, et al. 2007. The effects of calcium and vitamin D supplementation on blood glucose and markers of inflammation in nondiabetic adults. Diabetes Care 30: 980-986.
- Wu T, WC Willett, and E Giocannucci. 2009. Plasma c-peptide is inversely associated with calcium intake in women with plasma 25-hydroxy vitamin D in men. Journal of Nutrition 139: 547-554.
- Chiu KC, A Chu, VL Go, et al. 2004. Hypovitaminosis D is associated with insulin resistance and beta-cell dysfunction. American Journal of Clinical Nutrition 79:820-820.
- Lee P and R Chen. 2008. Vitamin D as an analgesic for patients with type 2 diabetes and neuropathic pain. Archives of Internal Medicine 168:771-772.
- Ginde AA, MC Liu, and CA Camargo. 2009. Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Archives of Internal Medicine 169: 626-632.