Kids who are deficient in vitamin D accumulated fat around the waist and gained weight more rapidly than kids who got enough vitamin D, a new U-M study suggests.

Vitamin D, which primarily is provided to the body by the sun, has been a hot topic in the United States lately. The federal standards for vitamin D intake have come under fire by public health professionals as being much too low, and disagreement continues over the proper amount of vitamin D necessary for optimal health.

Accumulation of abdominal fat, or central fat, may lead to a so-called apple body shape, which is commonly linked to increased risks of type 2 diabetes, heart disease and other chronic conditions later in life, says epidemiologist Eduardo Villamor, associate professor in the School of Public Health and senior author of the study.

Villamor worked with colleagues at the National University of Colombia and began the research while at Harvard.

“We found that the kids with the lowest vitamin D levels at the beginning tended to gain weight faster than the kids with higher levels,” Villamor says, and children with the lowest vitamin D levels had more drastic increases in central body fat measures. Vitamin D deficiency was also linked to slower growth in height among girls but not boys, he says.

Though vitamin D intake could be related to early obesity, it’s just part of a very complex picture, Villamor says.

Of all the children tested, 10 percent were vitamin D deficient, and another 46 percent of kids were insufficient, which meant they were at risk of becoming deficient.

“Interestingly, Bogota, Colombia is in a subtropical zone where one may not expect to find a lot of vitamin D deficiency since the assumption is that sunlight is abundant there, but there could be many reasons people in sub-tropical climates may not get enough sun exposure,” Villamor says. Indeed, previous studies have shown that populations in other subtropical areas such as Sao Paulo, Brazil and Costa Rica also may have vitamin D deficiency.

“These findings should motivate some discussion on ways to enhance vitamin D status of children there, although it will be necessary to confirm in intervention studies whether improvements in vitamin D status decrease the risk of childhood obesity and early development of chronic diseases,” he says.

In addition to sun exposure, other sources of vitamin D are fortified foods and supplements. Vitamin D supplementation has been shown to prevent some viral infections in school-age children, so there could be benefits on other outcomes as well, which need to be tested in future studies, Villamor says.

The paper, “Vitamin D deficiency and anthropometric indicators of adiposity in school-age children: a prospective study,” is available this month in the American Journal of Clinical Nutrition.