Researchers establish link between obesity, vitamin D levels

It is generally understood that obesity is pretty bad for your health. But now researchers are beginning to understand why--specifically, obesity is linked to diseases such as cancer, heart disease and diabetes. If you're obese, you likely have reduced levels of vitamin D, which influences cell growth, neuromuscular and immune function and inflammation reduction.

But there is good news, according to new research at the Fred Hutchinson Cancer Research Center in Seattle. Obese people can significantly increase their levels of vitamin D. All it takes is some really hard work and losing about 15 percent of your body weight.

"Determining whether weight loss helps change vitamin D status is important for understanding potential avenues for disease prevention," said researcher Caitlin Mason in a news release. Mason is lead author of a paper on the topic that appears in the American Journal of Clinical Nutrition. The year-long study followed 439 overweight-to-obese, sedentary, postmenopausal Seattle-area women between the ages of 50 and 75 randomly assigned to one of four groups: exercise only, diet only, exercise plus diet and no intervention. The women who lost 15 percent of their body weight saw a threefold increase in vitamin D.

"We were surprised at the effect of weight loss greater than 15 percent on blood vitamin D levels," said senior author Anne McTiernan in a release. "It appears that the relationship between weight loss and blood vitamin D is not linear but goes up dramatically with more weight loss. While weight loss of 5 percent to 10 percent is generally recommended to improve risk factors such as blood pressure, cholesterol and blood sugars, our findings suggest that more weight loss might be necessary to meaningfully raise blood vitamin D levels."

The reason this happens, researchers speculate, is that during weight loss vitamin D that is trapped in fat tissue is released into the blood and available for the body to use.

The next step is to try to understand the role vitamin D plays in chronic diseases and more studies are planned.

- take a look at the release
- and the abstract in the American Journal of Clinical Nutrition

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