Vitamin D deficiency in obese children may contribute to type 2 diabetes

Obese children have significantly lower levels of vitamin D and higher degrees of insulin resistance, according to a new study slated for publication in the January 2012 issue of Journal of Clinical Endocrinology & Metabolism.

While scientists don't fully understand the mechanisms linking obesity and vitamin D deficiency, past studies have correlated low vitamin D levels to type 2 diabetes.

“Although our study cannot prove causation, it does suggest that low vitamin D levels may play a role in the development of type 2 diabetes,” said Micah Olson, MD, The University of Texas Southwestern Medical Center and lead author of the study.

Researchers followed 411 obese children and 87 normal weight subjects. They measured vitamin D levels, blood sugar levels, serum insulin, body mass index (BMI) and blood pressure. In addition, participants self-reported their daily soda, juice and milk intake, their average daily fruit and vegetable intake, and if they skipped meals regularly.

“Poor dietary habits such as skipping breakfast and increased soda and juice intake were associated with the lower vitamin D levels seen in obese children,” said Olson. “Future studies are needed to determine the clinical significance of lower vitamin D levels in obese children, the amount and duration of treatment necessary to replenish vitamin D levels in these children and whether treatment with vitamin D can improve primary clinical endpoints such as insulin resistance.”

According to the National Institutes of Health, people absorb vitamin D from food or produce it in their skin when exposed to sunlight. People may become deficient in vitamin D if they stay or work indoors or live in climates with less sunlight. Lactose intolerance, a vegetarian diet and non-consumption of dairy products may also contribute to a deficiency.

Fortified foods like milk and cold cereal provide most of the vitamin D in the American diet, according to the National Institutes of Health. Very few natural foods contain vitamin D, but the best sources are the flesh of fatty fish and fish liver oils. Sun exposure and dietary supplements are other important sources.

Sources: Journal of Clinical Endocrinology & Metabolism, National Institutes of Health

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