Vitamin D appears to play an important role in the immune system. In a recent post about rheumatoid arthritis risk factors I mentioned that vitamin D appears to cut the risk of getting that terrible auto-immune disorder. Well, now comes a report from vitamin D researcher Cedric Garland of USCD about how type I auto-immune diabetes occurs at the highest rates where people get less sunshine and therefore get less vitamin D synthesized in their skin.

Sun exposure and vitamin D levels may play a strong role in risk of type 1 diabetes in children, according to new findings by researchers at the Moores Cancer Center at University of California, San Diego (UCSD) and the Department of Family and Preventive Medicine. This association comes on the heels of similar research findings by this same group regarding vitamin D levels and several major cancers.

In this new study, the researchers found that populations living at or near the equator, where there is abundant sunshine (and ultraviolet B irradiance) have low incidence rates of type 1 diabetes. Conversely, populations at higher latitudes, where available sunlight is scarcer, have higher incidence rates. These findings add new support to the concept of a role of vitamin D in reducing risk of this disease.

Ultraviolet B (UVB) exposure triggers photosynthesis of vitamin D3 in the skin. This form of vitamin D also is available through diet and supplements.

"This is the first study, to our knowledge, to show that higher serum levels of vitamin D are associated with reduced incidence rates of type 1 diabetes worldwide," said Cedric F. Garland, Dr. P.H., professor of Family and Preventive Medicine in the UCSD School of Medicine, and member of the Moores UCSD Cancer Center.

The study is published June 5 in the online version of the scientific journal Diabetologia.

Do I even need to mention that that vitamin D seems to also cut the risk of the killer auto-immune disorder Multiple Sclerosis? Want to avoid auto-immune disorders, cut your risk of cancer, and probably reduce your incidence of infectious diseases? Vitamin D delivers many benefits.

My Australian and Kiwi readers (and Chileans and Argentineans) are coming up on their shortest day of the year and they ought to be thinking about vitamin D supplementation. Northern hemisphere denizens who stay indoors the vast bulk of the time ought to consider vitamin D supplementation during the summer as well.