Although some observational studies found that having low levels of vitamin D increased a person’s risk of diabetes, researchers wanted to know if supplementing vitamin D would help prevent or delay the disease.
To find out, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) funded a large study called D2d. Here’s what the researchers found.
Vitamin D vs. placebo
More than 2,000 adults of varying ages, races, sex and body mass index volunteered to have their vitamin D levels checked. Approximately 80% of the participants had sufficient levels of vitamin D based on the U.S. RDA. The volunteers were divided into two groups; one group took 4,000 IU of vitamin D and one group took a placebo.
Every 3 to 6 months for an average of 2 years, the researchers screened the volunteers. At the end of the study, the team reported that:
- 293 of the 1,211 people in the group who took vitamin D supplements developed diabetes.
And
- 323 of the 1,212 people in the group who took the placebo developed diabetes.
The D2d study did not find a difference between the two groups in terms of the risk of high blood calcium levels and kidney stones, despite 4,000 IU of vitamin D is higher than the recommended dose.
These numbers did not represent a statistically significant difference.
Other ways to prevent diabetes
With no hope of vitamin D, the researchers presented other recommendations to prevent diabetes.
“While we continue to search for new ways to prevent the disease, we know that lifestyle change or the drug metformin remain effective methods to prevent type 2 diabetes,” explains Dr. Griffin P. Rodgers, director of the NIDDK. “We encourage the 84 million U.S. adults at high risk for developing type 2 diabetes to explore options like the CDC’s National Diabetes Prevention Program, available to communities throughout the country.”
