Calcium-rich dairy foods may help young women prevent bone loss associated with oral contraceptives, according to a study in the July 5 issue of the Journal of Clinical Endocrinology and Metabolism.

Researchers at Purdue University found that in active women who use birth-control pills, consuming dairy products that contain at least 1,000 milligrams (mg) of calcium per day prevented hip and spine bone loss associated with oral-contraceptive use.

During the one-year study, 154 women between 18 and 30 years of age were randomized to one of three groups: a control group consuming less than 800 mg of calcium per day, a medium dairy group consuming 1,000 to 1,100 mg of calcium per day and a high dairy group consuming 1,200 to 1,300 mg of calcium per day.

In all three diet groups, the researchers compared oral-contraceptive users to non-users. They periodically collected bone-mineral-density measurements and three-day food records throughout the year.

At the end of the year, women who used oral contraceptives and followed the medium or high dairy diet had significantly higher bone-mineral density in their hips and spines, compared to the low dairy group. Oral-contraceptive users consuming low-calcium diets were more susceptible to bone loss than non-users.

“The results of our study suggest it is very important that young women taking oral contraceptives get the recommended level of calcium (1,000 mg) in order to optimize the development of bone,” said Dorothy Teegarden, associate professor of foods and nutrition at Purdue University.

The authors note that women who use birth-control pills could reduce their risk of osteoporosis by approximately 3 percent to 10 percent over one year by consuming adequate dairy foods.

National Dairy Council