New research indicates that vitamin D supplements, even when taken in high doses, do not lower the risk of developing type 2 diabetes in older adults who are otherwise healthy. The study, conducted by researchers at the University of Eastern Finland, challenges earlier suggestions that vitamin D might protect against diabetes, particularly in individuals with low vitamin D levels.
The findings, published in Diabetologia, involved a randomized trial with nearly 2,300 participants aged 60 or older. Participants were assigned to receive either a placebo, 40 micrograms of vitamin D3, or 80 micrograms of vitamin D3 daily for five years. The primary outcome was the development of type 2 diabetes.
No Significant Reduction in Diabetes Risk
Over the five-year study period, 105 participants developed type 2 diabetes: 38 in the placebo group, 31 in the 40-microgram vitamin D3 group, and 36 in the 80-microgram vitamin D3 group. These results indicate no statistically significant difference in diabetes incidence across the groups. According to a university news release, the team observed no benefit from high-dose supplements on a person's blood sugar or insulin levels, or measures of overweight/obesity.
Jirki Vyrtanen, the lead researcher from the University of Eastern Finland, and his team concluded that for healthy, non-prediabetic individuals with sufficient vitamin D levels, increasing vitamin D intake does not alter the likelihood of developing diabetes or its associated risk factors.
Implications for Vitamin D Supplementation
These findings suggest that vitamin D supplementation may not be beneficial for preventing type 2 diabetes in healthy older adults who are not prediabetic. While vitamin D supplements may offer other health benefits, this study indicates they are ineffective in reducing diabetes risk in this population. The research adds to the growing body of evidence that questions the widespread use of vitamin D supplements for diabetes prevention in generally healthy individuals.
