Vitamin D intake could delay development of type 2 diabetes in adults with prediabetes: Study

USA: Higher vitamin D intake is linked to a 15% lower risk of developing type 2 diabetes in adults with prediabetes, according to results from a review of clinical trials. The review appeared in the Annals of Internal Medicine.

Prediabetes is a condition of having a higher-than-normal blood sugar level that is not high enough to be considered type 2 diabetes. In patients having prediabetes, long-term diabetes damage, particularly to the blood vessels, heart and kidneys, may already be starting. However, progression from prediabetes to type 2 diabetes isn't inevitable. 

Vitamin D is a fat-soluble vitamin available in or added to some foods as a supplement or produced by the body when ultraviolet rays from sunlight strike the skin. Vitamin D has many functions in the body, including a role in insulin secretion and glucose metabolism. Observational studies have found an association between having a low vitamin D level in the blood and a high risk of developing diabetes.

Researchers from Tufts Medical Center conducted a systematic review and meta-analysis of three clinical trials comparing vitamin D supplement impacts on diabetes risk.

The authors found that over a three-year follow-up period, new-onset diabetes occurred in 22.7 percent of adults who received vitamin D and 25 percent of those who received a placebo, which is a 15 percent relative reduction in risk. According to the authors, extrapolating their findings to the more than 374 million adults worldwide who have prediabetes suggests that inexpensive vitamin D supplementation could delay the development of diabetes in more than 10 million people.

In an accompanying editorial, University College Dublin and Food Safety Authority of Ireland authors highlight that previous data have demonstrated significant adverse effects of high vitamin D intake. They argue that professional societies promoting vitamin D therapy must warn physicians about required vitamin D intake and safe limits. They advise that this very-high-dose vitamin D therapy might prevent type 2 diabetes in some patients but may also cause harm.

Reference:

Anastassios G. Pittas, Tetsuya Kawahara, Rolf Jorde, Bess Dawson-Hughes, Ellen M. Vickery, Edith Angellotti, Jason Nelson, Thomas A. Trikalinos,and Ethan M. Balk, https://doi.org/10.7326/M22-3018