High levels of vitamin D, low-calorie diet may increase weight loss

Researchers at the University of Minnesota Medical School have found that people who have higher levels of vitamin D while on a low-calorie diet may increase weight loss — particularly abdominal weight.

“Our results suggest the possibility that the addition of vitamin D to a reduced-calorie diet will lead to increased weight loss in individuals with low levels of vitamin D,” Shalamar Sibley, MD, of the University of Minnesota Medical School, said in a press release. “Although I would caution against excess vitamin D intake, these studies may suggest another reason for individuals who have inadequate vitamin D levels to bring their levels into the recommended range.”

Sibley and colleagues conducted a study to assess whether vitamin D levels are associated with weight loss in 38 obese men and women. They measured two forms of vitamin D: the precursor form, 25-hydroxyvitamin D and the active hormonal form, 1,25-dihydroxyvitamin D at baseline. All participants had insufficient vitamin D levels at baseline.

Participants were followed for 11 weeks while randomly assigned to a diet program that included a daily caloric intake <750 of the estimated daily recommendation.

Baseline vitamin D levels predicted weight loss in a linear relationship, according to the researchers. For every one-unit increase of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, weight loss was increased by about one-quarter pound or more.

Moreover, higher baseline levels of either form of vitamin D predicted greater loss of abdominal fat.

The researchers cautioned that further research is warranted.

“Our findings need to be followed up by a controlled clinical trial to determine if there is a role for vitamin D supplementation to help people lose weight when reducing the number of calories consumed,” Sibley said.

This study was funded by the National Institutes of Health, University of Minnesota, and Pennock Family Endowment at the University of Minnesota.