While you may hear the most about vitamin D during peak flu season since it boost immune function, more evidence is mounting that suggests it could play a role in the prevention of numerous other health conditions. Recently, a 5 year study of 5,000 Australian adults was published that shows a 57% increase in risk of developing diabetes in subjects with below average levels of vitamin D. This may very well be a two way street though, because obesity and inactivity which are primary risk factors for diabetes are also potential causes for low vitamin D levels.
The body manufactures vitamin D as a response to natural sunlight, but is also found in other high protein foods like eggs and salmon. It is also available in supplement form, but research to show it helps as much as naturally occurring forms is inconclusive. It has previously been associated with lower risks of heart disease and certain types of cancer, but there seems to be a more direct link regarding diabetes.
More research is needed to prove the link between the two, but the thought now is that vitamin D plays a similar role to calcium in the release of insulin to the blood stream. The most common form, type 2 diabetes, is the result of the bodys inability to efficiently use insulin to control levels of blood sugar. The study measured vitamin D levels in over 5,000 people, and after 5 years measured them again. Roughly 200 participants had developed diabetes in that time, and they were the ones with the lowest levels of vitamin D.
American Diabetes Association