Weight Loss in Heavy, Obese Women Boosts Vitamin D Levels

FRIDAY, May 27 (HealthDay News) -- Older women who are overweight or obese and lose more than 15 percent of their body weight could significantly boost their levels of vitamin D, new research suggests.

The study, conducted by researchers at Fred Hutchinson Cancer Research Center, also indicates that the surge in vitamin D could help scientists explore new avenues for the prevention of chronic diseases such as cancer and diabetes.

"Since vitamin D is generally lower in persons with obesity, it is possible that low vitamin D could account, in part, for the link between obesity and diseases such as cancer, heart disease and diabetes," study author Caitlin Mason, a postdoctoral research fellow, said in a Hutchinson news release.

Vitamin D is fat-soluble nutrient that plays many important roles in the body, including promoting calcium absorption, reducing inflammation and influencing cell health and the immune system. It's found in certain foods, such as fatty fish, and produced naturally in the body through exposure to sunlight.

The study, published in the May 25 online issue of the American Journal of Clinical Nutrition, assigned 439 overweight or obese postmenopausal women to one of four regimens: exercise only, diet only, exercise plus diet and no intervention.

Although women who lost up to 10 percent of their body weight (10 to 20 pounds) through diet and exercise saw modest increases in vitamin D, those levels were roughly three times higher in women who dropped more than 15 percent of their body weight, regardless of what they ate.

"We were surprised at the effect of weight loss greater than 15 percent on blood vitamin D levels," study senior author Dr. Anne McTiernan, director of the Hutchinson Center's Prevention Center, said in the news release. "It appears that the relationship between weight loss and blood vitamin D is not linear but goes up dramatically with more weight loss."

McTiernan concluded the findings suggest the greater the weight loss, the more meaningful the surge in vitamin D levels.

The researchers noted, however, the degree to which vitamin D is available to the body during and after weight loss remains unclear. They also cautioned that more targeted research is needed to understand any link between vitamin D deficiency and chronic disease.

More information

The National Institutes of Health offers more information on the functions and sources of vitamin D.

--Mary Elizabeth Dallas
SOURCE: Fred Hutchinson Cancer Research Center, news release, May 25, 2011.