100 percent of obese adolescent girls tested as vitamin D deficient or insufficient in study published in the May issue of the Journal of Adolescent Health — a surprising result that some researchers believe is further evidence that the best way to get vitamin D levels up is through regular outdoor activity.

“The prevalence of low vitamin D status among obese adolescents in this study is greater than previously reported for this age group,” Dr. Zeev Harel, a pediatrician specializing in adolescent medicine at Hasbro Children’s Hospital in Providence, R.I., and the study’s lead author, said in a hospital news release. The release was written up in an article on Health Day News May 4.

What concerned researchers most: Treating the deficient teens with vitamin D supplements only raised the vitamin D levels to ‘normal’ in 28 percent of the cases.

“It’s more and more clear that vitamin D’s best and most natural source is UV exposure from sunshine,” Smart Tan Vice President Joseph Levy said. “Articles like these continue to point out that sun is the natural source of vitamin D, but short-change that truth by also saying that milk and fish are other sources. A suntan makes as much vitamin D in most people as 100 glasses of fortified milk, which is not a natural source. Clearly, nature’s source is the most abundant.”

To read the Health Day News story click here.