If you take calcium pills, they’ll help. If you don’t take them, they won’t. Seems pretty obvious, right? But there’s more to it.

Women who take the pills need to carefully follow doctors’ orders or they, too, can suffer bone fractures. A recent study shows that women who don’t take calcium supplements have more broken bones. But those who skip dosages have more fractures, too.

Most postmenopausal women need between twelve-hundred and fifteen-hundred milligrams of calcium every day. A six-ounce container of yogurt or eight-ounce glass of milk supplies about three-hundred milligrams of calcium. But the body doesn’t store excess calcium, so you can’t create a “calcium bank account.” If you’re getting enough, taking more won’t make a difference. But if you’re not getting enough, supplements can help.

The study tracked almost fifteen-hundred women aged seventy and older for five years. Half took six-hundred milligrams of calcium carbonate twice daily. The others took placebo… or “dummy” tablets.

Women were noncompliant if they took less than eighty percent of the recommended medication. During the study, sixteen percent of all participants had fractures. Only ten percent of compliant women had fractures versus fifteen percent of placebo users. But surprisingly, almost half the women were noncompliant. Many cited constipation as a calcium side effect that encourages noncompliance.

Still, women who take calcium have fewer fractures. Researchers suggest others seek to eat calcium-rich foods and take eight-hundred to one-thousand international units of vitamin D a day to help the body absorb this vital mineral.