Vitamin D May Lower Blood Sugar in Prediabetes

Study finds those with prediabetes who take vitamin D are more likely to reach normal blood sugar levels.

Published on Feb. 5, 2026

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A study analyzing data from nearly 4,500 people with prediabetes found that 18.5% of those who took vitamin D reached normal blood sugar levels, compared to 14% who took a placebo. Experts say vitamin D may help regulate blood sugar and insulin resistance, but caution that it should be viewed as part of an overall diabetes prevention plan, not a standalone solution.

Why it matters

Prediabetes is a serious condition that often leads to type 2 diabetes if lifestyle changes aren't made. This study suggests vitamin D could be a helpful addition to a diabetes prevention regimen, though more research is still needed to fully understand the connection.

The details

The study, published in the Journal of the Endocrine Society, looked at data from 10 clinical trials involving people with prediabetes. Researchers found that those who took vitamin D supplements were more likely to reach normal blood sugar levels compared to those who took a placebo. Experts believe vitamin D may help regulate blood sugar, insulin resistance, and inflammation - all of which are linked to diabetes risk. However, they caution that vitamin D should not replace other proven diabetes prevention strategies like diet, exercise, and weight management.

  • The study was published in February 2026.

The players

Sylvia Christakos, Ph.D.

A vitamin D researcher and professor of microbiology at Rutgers New Jersey Medical School.

Jessica Cording, R.D.

Author of The Little Book of Game Changers.

David Cutler, M.D.

A family medicine physician at Providence Saint John's Health Center in Santa Monica, CA.

Ankit Shah, M.D.

Assistant professor in the Division of Endocrinology, Metabolism, and Nutrition at Rutgers – Robert Wood Johnson Medical School.

Anastassios Pittas, M.D.

Study co-author and a professor of medicine at Tufts University School of Medicine.

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What they’re saying

“Vitamin D should be viewed as part of an overall diabetes prevention plan, not a stand-alone solution.”

— Anastassios Pittas, M.D., Study co-author and professor of medicine at Tufts University School of Medicine

“While vitamin D deficiency and diabetes are two separate issues that have different treatment strategies, there might be a benefit such that treating one issue may have positive spillover effects on the other.”

— Ankit Shah, M.D., Assistant professor in the Division of Endocrinology, Metabolism, and Nutrition at Rutgers – Robert Wood Johnson Medical School

What’s next

More research is still needed to fully understand the connection between vitamin D and blood sugar management in people with prediabetes.

The takeaway

This study suggests vitamin D may be a helpful addition to a comprehensive diabetes prevention plan, but it should not replace other proven strategies like diet, exercise, and weight management. Consulting with a healthcare provider is key for those with prediabetes looking to lower their risk of developing type 2 diabetes.