Can Vitamin D Help Reduce Risk of Type 2 Diabetes?

Recruitment for the first large-scale clinical trial has begun to determine if a vitamin D3 supplement (cholecalciferol) helps prevent or delay type 2 diabetes in adults who have prediabetes.

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The multiyear Vitamin D and Type 2 Diabetes (D2d) study will enroll about 2,500 patients across 20 study sites. The study’s aim is to learn if 4,000 IU vitamin D will prevent or delay type 2 diabetes in adults >30 years old with prediabetes. 

This dose is greater than the typical adult intake of 600–800 IU/day, but has been deemed appropriate for clinical research by the Institute of Medicine.

“Past observational studies have suggested that higher levels of vitamin D may be beneficial in preventing type 2 diabetes, but until this large, randomized and controlled clinical trial is complete, we won’t know if taking vitamin D supplements lowers the risk of diabetes,” said Anastassios G. Pittas, MD, the study’s principal investigator at Tufts Medical Center, Boston, MA.

Study researchers hypothesize that vitamin D can reduce the risk of diabetes risk by 25%. The double-blind study will also assess if sex, age or race affect the potential of vitamin D in reducing the risk of diabetes. Patients will be randomized to receive vitamin D or placebo. 

Check-ups for the study will occur twice a year, and patients will receive regular health care through their own health care providers. The study will continue until enough people have developed type 2 diabetes to be able to make scientifically valid comparison between the two groups–likely to be about four years.

This study is funded by the National Institutes of Health.

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