ROCHESTER, Minn., Aug. 17 (UPI) -- Vitamin D supplements showed no benefit for heart health or lowering the risk for diabetes in obese teenagers, and may increase cholesterol and triglycerides for them, according to a recent small study.
While vitamin D is increasingly being used in doses 5- to 10-times its recommended daily intake as a homeopathic or complementary treatment for obesity, the science is not entirely clear.
Previous studies have linked vitamin D deficiency with obesity, as well as complications of obesity just as cardiovascular disease and insulin resistance, but the risks of developing toxicity from taking too much of the supplements are real.
"After three months of having vitamin D boosted into the normal range with supplements, these teenagers showed no changes in body weight, body mass index, waistline, blood pressure or blood flow," said Dr. Seema Kumar, a pediatric endocrinologist at the Mayo Clinic's Children's Center, in a press release. "We're not saying the links between vitamin D deficiency and chronic diseases don't exist for children -- we just haven't found any yet."
Researchers treated 19 teenagers between the ages of 13 and 18 with a high-level dosage of vitamin D for 3 months, using endothelial function as an overall measure of the supplement's effects. They also monitored calcium, fasting lipids, glucose, insulin and high-sensitivity C-reactive proteins in the participants, all of which vitamin D would be expected to effect.
They found that while levels of vitamin D had been suitably increased for health levels, none of the expected benefits on endothelial function could be detected.
In addition to not finding the health effects of the supplements, researchers mention that vitamin D toxicity, called hypervitaminosis, can result in poor appetite, nausea, vomiting, and kidney complications.
"I have been surprised that we haven't found more health benefit," said Dr. Kumar. "We're not saying it's bad to take vitamin D supplements at reasonable doses, and we know most obese teens are vitamin D deficient. We're just saying the jury is still out on how useful it is for improving overall health in adolescents."
The study is published in Pediatric Obesity.