An epidemiological study conducted by researchers at University of California San Diego School of Medicine and Seoul National University suggests that people deficient in vitamin D may be at much greater risk of developing diabetes.
For the study, the researchers identified the minimum healthy level of 25-hydroxyvitamin D in blood plasma to be 30 nanograms per milliliter. This is 10 ng/ml above the level recommended in 2010 by the Institute of Medicine, now part of The National Academies, a health advisory group to the federal government. Many groups, however, have argued for higher blood serum levels of vitamin D, as much as 50 ng/ml.
The research team found that people with blood levels of 25-hydroxyvitamin D that were above 30 ng/ml had one-third of the risk of diabetes and those with levels above 50 ng/ml had one-fifth of the risk of developing diabetes.
People with 25-hydroxyvitamin D levels below 30 ng/ml were considered vitamin D deficient. They were up to five times at greater risk for developing diabetes than people with levels above 50 ng/ml.