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Vitamin D, the so-called “sunshine vitamin” was once only considered important for bone health, but recent research suggested the nutrient is important to achieve optimum overall health. Low levels of vitamin D have been increasingly blamed for everything from cancer and heart disease to diabetes.
Since overweight and obese women are at risk for chronic diseases and tend to have less-than-optimal levels of vitamin D, Dr. Caitlin Mason, Ph.D., research fellow at Fred Hutchinson Cancer Research Center wanted to know if heavy menopausal women could increase their vitamin D blood levels with weight loss. It turns out those who lost more than 15 percent of their body weight experienced significant increases in the fat-soluble vitamin.
“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," said Mason, the paper’s lead author, published online in the American Journal of Clinical Nutrition. “Determining whether weight loss helps change vitamin D status is important for understanding potential avenues for disease prevention.”
The year-long study – one of the largest ever conducted to assess the effect of weight loss on vitamin D – involved 439 overweight-to-obese, sedentary, postmenopausal Seattle-area women, ages 50 to 75, who were randomly assigned to one of four groups: exercise only, diet only, exercise plus diet and no intervention.
According to the National Institutes of Health, vitamin D plays many important roles in the body. It promotes calcium absorption and is needed for bone growth and bone healing. Along with calcium, vitamin D helps protect older adults from osteoporosis and youngsters from rickets (soft bones).
The nutrient also influences cell growth, neuromuscular and immune function, and reduces inflammation. Many gene-encoding proteins that regulate cell proliferation, differentiation, and programmed cell death necessary to prevent cancer are modulated in part by the vitamin.