Vitamin D associated with a 29% reduced risk of type 1 diabetes.

In a new study published last week in the Archives of Disease in Childhood reported that giving children vitamin D supplements in infancy may decrease their risk of developing type 1 diabetes later in life. Utilizing previous studies, British researchers found significant evidence that supplements of the vitamin were associated with a 29% reduced risk of the disease.

Subjects in the studies ingested vitamin D supplements beginning at birth and continued from there, each for variable time periods. They were tracked for 15 to 30 years. Types and doses of vitamin D supplements varied from subject to subject, and were not always reported. But it appears that supplementation was roughly 1-mcg, or 400 I.U. of vitamin D daily. The amount typically found in infant multivitamins.

Dr. Christos Zipitis, a pediatrician at the Stockport NHS Foundation Trust was the lead author of the paper. Based on data from three case-control studies which tracked 6,455 subjects, found that infants who were given supplements were 29% less likely to develop type 1 diabetes compared to those who never got extra vitamin D.

Dr. Zipitis, reviewing five studies, also found evidence that the vitamin's protective effect increased with larger doses and consistant supplementation. "[Our study] provides the strongest evidence to date that vitamin D might be protective against type 1 diabetes in later life," says Zipitis. "Obviously we're based on other studies, so this has come up before. The new thing with our study is the strength of the association and the confidence with which we can talk about it."

The studies did have some limitations however... it did not take into account how much vitamin D the subjects were getting from other sources. It also did not reveal if the subjects were vitamin D deficient in the first place. But some of the participants had rickets, a bone disorder casued by extreme vitamin D dificiency and Zipitis reported that they "were at a much higher risk of developing type 1 diabetes — I think about three times higher than the rest of the population, which would suggest that the higher the level of vitamin D in your body, the less likely you are to develop type 1 diabetes."

This is not really a big surprise, as extensive past research has basically come to the same conclusion. Sunshine triggers vitamin D production in the body, so countries with lots of sunshine naturally have a lower incidence of type 1 diabetes. And conversly, type 1 diabetes crop up more often in less sunnier places during winter months when there is less sunshine. And when doctors check vitamin D blood levels of newly diagnosed type 1 diabetes patients, they are generally lower than average.

Dr. Zipitis says, "In the U.K. and other European countries, we haven't got the right UV radiation for most of the year. With all the scares about skin cancer, when people go outside, they're covered with sunblock, which doesn't allow the conversion of UV light into vitamin D. That's where the supplements come in."

It should also be noted that insufficient blood levels of vitamin D have also been linked to other health problems... above and beyond type 1 diabetes and rickets. Rheumatoid arthritis and multiple sclerosis have been associated with vitamin D deficiency as well as cardiomyopathy, a rare but serious heart problem.

On the up side, there appears to be additional benefits of vitamin D supplementation beyond the prevention of these diseases: better bone health, stronger muscles and fewer fractures in adults are a few. Some research studies are suggesting that vitamin D can reduce the risk of various cancers as well. A study of 1,179 postmenopausal women published in the American Journal of Clinical Nutrition last year found that women who took calcium and 1,100 I.U. of vitamin D daily had 80% fewer cancers than women who took a placebo or calcium alone.