Vitamin D supplementation may slow the progression of prediabetes and type 2 diabetes in those newly diagnosed by improving insulin sensitivity and beta cell function, according to a small new study published in the European Journal of Endocrinology.
Vitamin D is a fat-soluble vitamin involved in a number of critical processes in the body, including maintaining bone health, preserving immune function and reducing chronic inflammation. Deficiency of the vitamin is common worldwide, affecting an estimated three quarters of teens and adults the United States population, and the condition has been linked with a variety of serious health issues, including type 2 diabetes.
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The researchers looked at 96 people who were at high risk of developing type 2 diabetes or who had recently been diagnosed with the condition. The participants were assigned to take either 5,000 IU of vitamin D for six months, while the others were assigned to take a placebo (inactive treatment). (Average daily recommended amounts of vitamin D from the Food and Nutrition Board are currently from 400–800 IU, with up to 4,000 IU daily considered safe.)
At the end of the study, subjects filled out questionnaires about their weekly sun exposure (sunlight is a source of vitamin D) and had various health markers measured. Although only 46% of the participants were identified as having low vitamin D at the start of the study, the researchers found that those receiving vitamin D supplementation had increased insulin sensitivity in their muscle tissue and improved function of beta cells (the cells in the pancreas that produce insulin).
These findings differed from trials in people with long-standing type 2 diabetes, which had shown no benefit of vitamin D supplementation. The reasons for these differences are unclear, the researchers state, but may be due to longer treatment being needed or to “improvements in metabolic function” being harder to detect in those with longstanding diabetes.
“Type 2 diabetes and prediabetes are a growing public health concern and although our results are promising, further studies are required to confirm our findings, to identify whether some people may benefit more from this intervention, and to evaluate the safety of high-dose vitamin D supplementation in the long term,” noted lead research Claudia Gagnon, MD. “Until then I would suggest that current vitamin D supplementation recommendations be followed.”
Want to learn more about vitamin D? Read “Vitamin D: Making Sure You Get Enough.”
Senior Digital Editor for DiabetesSelfManagement.com, Fennell has 16 years’ experience specializing in diabetes and related health conditions. Based in New York City, she has a degree from Columbia University.