While researchers have long suspected that vitamin D might help reduce the risk of developing an autoimmune disease, a US study recently provided the first evidence of such a causal link.
Nearly 26,000 subjects followed for five years
In the context of works published in the British Medical Journal, Karen Costenbader and his colleagues from Brigham and Women’s Hospital de Boston studied the effects of vitamin D in nearly 26,000 subjects aged 50 or over, randomly divided into two groups who received vitamin D supplements or a placebo. The team followed the participants for regarding five years to measure the development of autoimmune diseases, including rheumatoid arthritis, autoimmune thyroid disease and psoriasis.
« Animal studies have shown vitamin D to benefit the immune system, but this is the first time we’ve shown it can prevent autoimmune conditions in humans. “, highlighted Costenbader. « What’s great regarding randomized trials is that they really answer the question of causation. »
The study found that a dose of 2,000 international units (IU) of vitamin D per day reduced the risk of developing an autoimmune disease by 22% compared to placebo. This is a dose five times higher than that recommended by most health organizations (400 IU).
Although it is not known exactly how vitamin D prevents autoimmune diseases, it is known that it is transformed in the body to produce an active form which can modify the behavior of immune cells. ” There are tons of potential mechanics “, say the authors of the study. ” It might be that vitamin D helps the immune system distinguish between normal body tissue and disease-causing microbes, or that it helps decrease inflammatory responses. »
“It is essential to discuss this with your doctor beforehand”
Costenbader now advises his patients to take 2,000 IU of vitamin D a day, if they are of the required age and if it does not present any danger to their health. “ It is essential to discuss this beforehand with your doctor, in order to ensure that there are no harmful interactions. “, she underlines.
His team is currently continuing the trial to determine precisely how long the benefits last and hope to start a new one to explore the effects of such vitamin D supplementation in younger subjects.
