Older women with low levels of vitamin D are more likely to struggle with weight gain than those who get enough of the “sunshine vitamin,” new research shows.
The study, funded by the National Institutes of Health and published in the Journal of Women's Health, tracked more than 4,600 women – ages 65 and older – for a 5-year period and found those with insufficient levels of vitamin D in their blood gained about two pounds more than those with adequate amounts.
Although the actual weight differences were small, lead research Dr. Erin LeBlanc – an endocrinologist with the Kaiser Permanente Center for Health Research – said the findings are significant because most older women have low levels of the beneficial vitamin.
"This is one of the first studies to show that women with low levels of vitamin D gain more weight, and although it was only two pounds, over time that can add up," she said. "Nearly 80 percent of women in our study had insufficient levels of vitamin D. A primary source of this important vitamin is sunlight, and as modern societies move indoors, continuous vitamin D insufficiency may be contributing to chronic weight gain."
The U.S. Preventive Services Task Force recently noted many healthy postmenopausal women may need higher doses of the vitamin to prevent fractures, but that there isn't enough evidence to recommend supplements for younger people.
LeBlanc said the new study doesn’t challenge those recommendations, but added: “We would need to do more studies before recommending the supplements to keep people from gaining weight. Since there are so many conflicting recommendations about taking Vitamin D for any reason, it's best if patients get advice from their own health care provider."
She noted about 60 percent of the participants remained at a stable weight during the study period, 27 percent lost more than 5 percent of their body weight, and 12 percent gained more than 5 percent of their body weight.
Nearly 80 percent had less than 30 nanograms per millimeter of vitamin D in their blood — the level defined as sufficient by The Endocrine Society. Of the 571 women who gained weight during the study, those with insufficient vitamin D levels gained more — 18.5 pounds over five years — than women who had sufficient levels (who gained 16.4 pounds over the same period).