Can Vitamin D Reduce the Risk of Type 2 Diabetes? The NIH Announces the First Large-Scale Clinical Trial to Investigate.

The National Institutes of Health (NIH) recently announced it will provide millions of dollars in funding for the first large-scale clinical trial to determine whether vitamin D supplements can reduce the risk of type 2 diabetes. The multiyear trial, known as the Vitamin D and Type 2 Diabetes study (D2d) will recruit about 2,500 people with prediabetes (30 years or older) from 20 sites nationwide. Half the study’s participants will take a daily dose of 4,000 international units (IU) of vitamin D – significantly more than the typical daily vitamin D intake of 600-800 IUs, though still well within clinical research guidelines – while the other half will take a placebo. The study is currently recruiting, and information is available both at ClinicalTrials.gov and at the D2d Study website.

The study’s organizers note that the use of vitamin D has increased significantly over the last 15 years as it has earned a reputation for numerous health benefits, including reducing the risk of diabetes. While there is some evidence from observational studies to support such a link, there’s no clinical trial data that can demonstrate a real link between use of vitamin D supplements and reduced risk of diabetes. Researchers believe substantial vitamin D intake could reduce the risk of diabetes by as much as 25%. Vitamin D is primarily involved in enhancing the absorption of calcium and phosphates in the intestines, and previous research has demonstrated a link to increased bone health and reduction in death rates for elderly women. Please inform any family members or friends who may have diabetes about this study – they can call 617-636-3232 or email d2d@tuftsmedicalcenter.org. —AW