High-Dose Vitamin D Supplements Won’t Prevent Diabetes in Healthy Seniors

Taking even high doses of supplementary vitamin D won’t lower an older person’s odds for type 2 diabetes, new research confirms.

Vitamin D supplements may have other benefits, but in otherwise healthy folks with sufficient levels of the nutrient, “our findings do not suggest benefits of long-term moderate- or high-dose vitamin D₃ supplementation” in warding off type 2 diabetes, the team of Finnish researchers concluded.

They published their findings Dec. 2 in the journal Diabetologia.

The new research followed on data from other studies that had suggested that people with especially low levels of vitamin D might face a higher risk for diabetes. That was true for people who were already prediabetic, especially.

So could a relatively high dose of vitamin D supplements help lower type 2 diabetes rates among people without prediabetes — those at no special risk for the blood sugar disease?

To find out, researchers led by Jirki Vyrtanen, from the University of Eastern Finland, randomly assigned nearly 2,300 people aged 60 or older to receive either placebo pills or 40 or 80 micrograms of vitamin D3 supplements per day, for five years.

At the end of the five years, “105 participants developed type 2 diabetes: 38 in the placebo group, 31 in the group receiving 40 micrograms of vitamin D3 per day, and 36 in the group receiving 80 micrograms of vitamin D3 per day,” according to a university news release.

In other words, there were no significant differences in the rate at which people developed type 2 diabetes, regardless of how much supplemental vitamin D they took.

Vytanen’s team also saw no benefit from high-dose supplements on a person’s blood sugar or insulin levels, or measures of overweight/obesity.

The bottom line, according to the researchers: For any healthy, non-prediabetic person with healthy vitamin D levels, upping intake of the vitamin won’t alter your odds for diabetes or its common risk factors.

More information

Find out more about vitamin D and health at the U.S. National Institutes of Health.

SOURCE: University of Eastern Finland, news release, Dec. 2, 2024