Nutrition News: Can Vitamin D Help Prevent Diabetes?
Three in 4 Americans have a vitamin D deficiency, according to the Academy of Nutrition and Dietetics. It's a growing problem.
New research finds that those deficient may be at a greater risk of developing Type 2 diabetes.
In a new study published in Diabetes Care, high-risk patients with the highest blood levels of vitamin D were 28 percent less likely to develop Type 2 diabetes than those with the lowest vitamin D levels.
Tufts University researchers studied 2,039 participants in the Diabetes Prevention Program. Unlike past studies that measured vitamin D status only once, blood levels of vitamin D were tested multiple times over an average 2.7 years. After adjusting for other diabetes risk factors, the researchers found that those in the top one-third of vitamin D status were significantly less likely to develop diabetes.
In an epidemiological study conducted by researchers at University of California San Diego School of Medicine and Seoul National University, scientists came to a similar conclusion. Their findings were reported in PLOS One journal online.
Scientists studied a cohort of 903 healthy adults (mean age: 74) with no indications of either pre-diabetes or diabetes during clinic visits from 1997 to 1999, and then followed the participants through 2009. Vitamin D levels in blood were measured during these visits, along with fasting plasma glucose and oral glucose tolerance.
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Over the course of time, there were 47 new cases of diabetes and 337 new cases of pre-diabetes, in which blood sugar levels are higher than normal but not yet high enough to be categorized as Type 2 diabetes.
For the study, the researchers identified the minimum healthy level of 25-hydroxyvitamin D in blood plasma to be 30 nanograms per milliliter.
"We found that participants 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," said first author Dr. Sue Park, in the Department of Preventive Medicine at Seoul National University College of Medicine.
Researchers considered people 25-hydroxyvitamin D levels below 30 ng/ml vitamin D deficient. These people, the researchers found, were at up to five times greater risk for developing diabetes than people with levels above 50 ng/ml.