Vitamin D Does Not Prevent Diabetes, New Study Finds

Vitamin D is very good for you but, apparently, it does not prevent diabetes in folks who are already at an elevated risk.  A new study has investigated existing evidence from observational studies that low levels of Vitamin D can contribute to diabetes, but that is no longer the accepted understanding. 

D2d Project—one of the largest studies of this type—has now reported that taking a substantial vitamin D supplement, every day, does not seem to help those most at risk for developing type 2 diabetes. The study aimed, specifically, at discerning a direct link between the two, but, indeed, found none. 

The study found that more than 50 percent of adults in the US take nutritional supplements, either including or in addition to vitamin D supplements.  The study also found that vitamin D use has increased quite a bit over the past two decades.  These trends, then, inspired the study, which evaluated the safety of taking as much as 4,000 daily units of vitamin D. This is far greater than the average daily recommended dose (between 600 and 800 IU per day), but still within the limits the Institute of Medicine have redeemed safe and appropriate for clinical research. 

The researchers say they found no difference in both the number and frequency of the predicted side effects like high blood calcium levels and kidney stones when compared against placebo groups.  

NIDDK D2d Project Scientist Myrlene Staten, MD explains, “Observational studies have reported an association between low levels of vitamin D and increased risk for type 2 diabetes.  Additionally, smaller studies found that vitamin D could improve the function of beta cells, which produce insulin. However, whether vitamin D supplementation may help prevent or delay type 2 diabetes was not known.”

In summary, the study found there is no link between large amounts of vitamin D and Type-2 diabetes prevention. Of course, the recommended amount of Vitamin D may still contribute to decreased risk of a variety of health outcomes as part of a healthy (nutritious) lifestyle. 

The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), which is part of the United States National Institutes of Health.  Also, the study was presented at the 79thScientific Sessions of the American Diabetes Association and has been published in the New England Journal of Medicine.