Study Questions Bone Benefits of Calcium, Vitamin D

Taking calcium and vitamin D doesn't necessarily protect the bones of older women. That's the news from the same Women's Initiative Study that said low-fat diets aren't all that beneficial in fighting heart disease and other ailments.

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Well, first we find out a low fat diet isn't necessarily healthier than a regular diet. Now comes another surprise on the health front. Calcium and vitamin D supplements may not help protect older women from osteoporosis. NPR Patricia Neighmond reports on the latest results from the seven year, 18 million dollar Women's Initiative Study. It's the same one that raised questions about the benefit of a low fat diet.

PATRICIA NEIGHMOND reporting:

Barbara Duncan is probably typical of many female consumers. She just turned 40 and since her early 30s she's been taking calcium and vitamin D supplements.

Ms. BARBARA DUNCAN (Consumer): I'm taking 1,000 milligrams of calcium minimum per day and 400 milligrams of vitamin D. It's actually in the calcium.

NEIGHMOND: And like many of us, she's hoping these supplements will protect her.

Ms. DUNCAN: I'm hoping I'll be able to age and not be breaking my hips and my bones, keep me strong, strong bones, and I won't be a woman with a humped over back.

NEIGHMOND: The results from this study say, well, maybe. Researchers followed over 32,000 women between the ages of 50 and 79. About half were assigned to take what Duncan takes, 1,000 milligrams of calcium and 400 units of vitamin D every day. The other half took a placebo. After two bone density tests over seven years, researchers found this possibly surprising result. Among women taking supplements, there was only a slight gain in bone mass and virtually no significant difference in broken hips compared to those on placebo.

Researchers are quick to say this doesn't mean women should throw out their calcium pills.

Dr. Rebecca Jackson is an endocrinologist at Ohio State University, and lead author of this study.

Dr. REBECCA JACKSON (Endocrinologist, Women's Initiative Study Author): Post-menopausal women, especially women over the age of 60, can gain a modest benefit in preserving hip bone mass and preventing hip fractures from taking calcium plus vitamin D.

NEIGHMOND: Women over 60 are at greater risk for bone fractures and for them there was a 21 percent decrease in broken hips compared to placebo. And a greater benefit was found as well for women who faithfully took the supplements.

Dr. JACKSON: For women who took the full dose of 1,000 milligrams of elemental calcium and 400 units of vitamin D3, they experienced a significant 29 percent decrease in hip fractures, which was four fewer hip fractures per 10,000 women.

NEIGHMOND: Some researchers say the benefits of calcium might've been greater if the women had taken more vitamin D. They took only 400 units and many doctors now recommend twice that.

Dr. Joe Finkelstein is one of them. He's an endocrinologist at Harvard Medical School. He says vitamin D helps the body absorb calcium. The findings of this study, he says, suggest that for many women, calcium and vitamin D is only the starting point when it comes to protecting bones.

Dr. JOE FINKELSTEIN (Endocrinologist, Harvard Medical School): I actually think that most women should have a bone density test once they enter the menopause, and use that information to help determine whether or not they need therapy in addition to calcium and vitamin D to prevent bone loss.

NEIGHMOND: Drugs like disphosphanates, for example, that really target and shore up bones. But even if women need this extra treatment, Finkelstein says they should still get the recommended daily allowance, 1,000 milligrams of calcium and 400 units of vitamin D.

Women can get that from supplements or from food and food may just be the better option. Women in the study who took the supplement saw an increase in kidney stones. So women might want to take to heart the advice of consumers like Barbara Duncan, who knows where to find her calcium. In food.

DUNCAN: Your dark leafy vegetables have it, and milk, of course. But I prefer to take, eat the broccoli and the dark lettuce, the dark, dark vegetables have lots of calcium.

NEIGHMOND: Calcium is easier to digest in food, another reason why doctors recommend that when women take their supplements, they take it with meals. Patricia Neighmond, NPR News.

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