Vitamin D fails to prevent type 2 diabetes in a large study

If you are talking about vitamin D and you expect it to lower your risk of getting type 2 diabetes with age, it's time to lower your expectations.
A new study, the largest of its kind, has shown that consumption of 4,000 international units (IU) per day, which is the upper limit of the recommended intake, can double the amount of vitamin D in the body. blood, but gives most people about the same chances of developing blood sugar problems as people who do not take vitamin.
After about 2.5 years, diabetes appeared at a rate of 9.4% per year with vitamin D supplements and 10.7% with placebo capsules, an insignificant difference. All patients were already at high risk of developing type 2 diabetes and 80% already had adequate levels of vitamin.
For the 5% of the population "with very low levels of vitamin D, there seems to be an advantage, but we urge caution and do not ask people to overreact," said Dr. Anastbadios Pittas, lead author , to Reuters Health during a phone interview.
Even though the vitamin helped this group reduce their risk of diabetes – and the number was too small to prove it – "these people will still have to take vitamin D so that it does not change the recommendations," said Dr. Pittas, co-director of the Diabetes and Lipids Center at the Tufts Medical Center in Boston.
Vitamin D also keeps bones healthy and doctors can also recommend a supplement for other reasons. Many foods add vitamin.
The study, published online by the New England Journal of Medicine and at a meeting of the American Diabetes Association in San Francisco, focused on 2,423 volunteers at high risk of developing the early-onset version of the disease. which can often be prevented diet and exercise.
According to the American Diabetes Association, about 29 million Americans already suffer from type 2 diabetes. This is the seventh leading cause of death in the United States. More than 84 million adults are at risk of contracting the disease.
Previous research has shown that people with low levels of vitamin D are at higher risk. The new study, known as D2d, was designed to test whether supplementation would reduce the chances of success.
All volunteers met two out of three criteria for pre-diabetes, which made it more likely that vitamin D – if it was effective – would help them.
In the end, 616 developed diabetes: 293 in the vitamin D group and 323 under treatment with placebo. But when the researchers adjusted the number of patients participating in the study and other factors, they found that the risks of developing type 2 diabetes were too similar to indicate that vitamin D was doing a great deal. difference.
In contrast, previous studies have shown that lifestyle changes, such as diet and exercise, can reduce by 58% the chances of developing type 2 diabetes over a similar period, said the Dr. Deborah Wexler of the Mbadachusetts General Hospital Diabetes Center in an editorial of the Journal.
Metformin, a preventative medicine, can reduce it by 31%, she said.
The D2d study volunteers who took vitamin D had a similar rate of side effects to those who received placebo.
Reports published in 2016 on two diabetes-preventive vitamin D tests, one conducted in Norway and the other in Japan, also found that type 2 levels were lower with vitamin, but that the differences were, once again, not large enough to be offset. statistically significant.
"Any benefit of vitamin D in preventing diabetes, if it exists, is modest and obviously does not relate to a sufficient vitamin D population," said Dr. Wexler. The question of whether this could help the few people suffering from vitamin D deficiency remains unanswered.
"The message is that there is no magic pill," said Dr. Pittas. "Weight loss and increased physical activity remain the best way to prevent diabetes."