Sunlight's Vitamin for Heavy Teens

Vitamin D may improve diabetes risk factors in obese teens

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) In recent decades, obesity rates among children and teens have skyrocketed, putting many young people at risk of diabetes. Research has suggested that a lack of vitamin D may play a role in this risk.

According to a recent study, vitamin D supplements may improve certain factors that increase the risk of type 2 diabetes in obese teens. In other words, vitamin D supplements may help obese teens keep diabetes at bay.

Study results showed that obese teens who took vitamin D supplements had reduced levels of insulin and insulin resistance, which may mean better blood sugar control – an important element in preventing diabetes.

"Learn about natural ways to lower your diabetes risk."

The study was conducted by Catherine A. Peterson, PhD, RD, of the Department of Nutrition and Exercise Physiology at the University of Missouri School of Medicine, and colleagues.

According to background information in the study, obese teens have a higher risk of vitamin D deficiency, or low levels of vitamin D. In addition, poor vitamin D levels have been linked to higher rates of metabolic syndrome (a group of risk factors that contribute to heart disease and diabetes) and type 2 diabetes in both adults and teenagers.

Therefore, Dr. Peterson and colleagues set out to determine the safety and effectiveness of vitamin D supplementation in obese teens, and whether increases in blood levels of vitamin D were associated with markers of diabetes risk. These markers included insulin sensitivity, insulin resistance and inflammation.

Insulin is a natural hormone that helps the body turn sugar from food into energy for the body. People with type 2 diabetes become less sensitive to insulin, leading to higher levels of blood sugar.

This small study included 35 obese teens who were randomly assigned to take either 4,000 IU of vitamin D per day or placebo (fake supplements). The researchers measured changes to BMI (a measure of body fat using height and weight), inflammatory markers, protein markers of diabetes risk, fasting blood sugar levels, fasting insulin (insulin while not eating) levels and insulin resistance.

After six months, there were no significant differences between those who took vitamin D and those who did not in terms of BMI, inflammatory markers in the blood and blood sugar levels. However, participants who took vitamin D had improvements in other measures of diabetes risk.

Vitamin D supplementation led to increases in 25-hydroxy vitamin D – a measure of how much vitamin D is in the body. The normal range of 25-hydroxy vitamin D is 30 to 74 ng/mL. After six months, 25-hydroxy vitamin D increased by 19.5 ng/mL in participants who took vitamin D, compared to 2.8 ng/mL among those did not take vitamin D supplements.

Fasting insulin decreased by 6.5 μU/mL in those who took vitamin D, while fasting insulin increased by 1.2 μU/mL in those who did not take vitamin D. The normal range of fasting insulin varies from person to person. However, decreases in fasting insulin are generally considered an improvement, as it is a sign that the body is not overcompensating for rising blood sugar.

Results also showed a decrease leptin-to-adiponectin ratio in participants who took vitamin D. Participants who did not take vitamin D experienced an increase in this ratio. A leptin-to-adiponectin ratio is a ratio of two proteins in the body in which a higher number indicates a higher diabetes risk.

"By increasing vitamin D intake alone, we got a response that was nearly as powerful as what we have seen using a prescription drug," said Dr. Peterson in a University of Missouri press release. "We saw a decrease in insulin levels, which means better [blood sugar] control, despite no changes in body weight, dietary intake or physical activity."

Body weight, diet and physical activity are all factors that affect diabetes risk.

"The vitamin D dosage we gave to the obese adolescents in our study is not something I would recommend for everyone," said Dr. Peterson. "For clinicians, the main message from this research is to check the vitamin D status of their obese patients, because they're likely to have insufficient amounts. Adding vitamin D supplements to their diets may be an effective addition to treating obesity and its associated insulin resistance."

Vitamin D is good for one's health for many reasons. It promotes healthy bones, muscles and nerves. While people can get the vitamin through supplements, vitamin D can also enter the body through exposure to sunlight.

According to Dr. Peterson, low vitamin D is a common problem. However, it can be very harmful to people who are obese.

"What makes vitamin D insufficiency different in obese individuals is that they process vitamin D about half as efficiently as normal-weight people," she said. "The vitamin gets stored in their fat tissues, which keeps it from being processed. This means obese individuals need to take in about twice as much vitamin D as their lean peers to maintain sufficient levels of vitamin D."

The study by Dr. Peterson and colleagues was published in the American Journal of Clinical Nutrition. The research was funded by the J.R. Albert Foundation. No conflicts of interest were disclosed.

Reviewed by: 
Review Date: 
March 27, 2013
Last Updated:
April 1, 2013