Bone Up on Calcium

Yes, it’s a bone builder. But this little mineral does so much more. Learn why else you need it―and how best to get it.

Other less expected sources: You can also fill up on fortified breakfast cereals, fortified juices, and many soy products, including tofu. If you swap your regular six-ounce glass of orange juice for one with added calcium, say, you’ll get at least 200 milligrams in a few gulps. Another option: Add nonfat powdered milk to smoothies, soups, casseroles, and puddings. A third of a cup can give you more than 30 percent of what you need each day.

What helps your body absorb it: Vitamin D. The easiest way to get your recommended daily allowance of 400 international units (I.U.) is to spend 10 to 15 minutes outdoors two to three times a week (your body produces vitamin D when exposed to sunlight). Or take a 400 I.U. supplement each day.

What causes your body to lose it: Sodium, by way of salt intake, is the biggest dietary offender, says Connie Weaver, Ph.D., a professor of foods and nutrition at Purdue University, in West Lafayette, Indiana. As it passes through your body, sodium takes calcium out with it. Also, some foods, like sweet potatoes and beans, contain acids that adversely affect how well the body absorbs the calcium in those foods. Calcium itself inhibits the body’s absorption of iron, so avoid consuming calcium- and iron-rich foods in the same meal.

How to tell if you’re getting enough: There are no early signs that you’re calcium deficient (those white spots on nails aren’t related). And when late signs, such as fractures, show up, you’ve already lost significant bone mass. The best way to know if you’re consuming enough is to track your diet for a few days. And if you have a family history of osteoporosis, ask your doctor about a bone-density scan, which can indicate the beginnings of bone loss.

When to take a supplement: If you know you’re lacking or if you’re on a low-calorie diet, consider supplements. They usually contain calcium citrate or calcium carbonate. Both are used equally well by the body, but calcium carbonate is best absorbed when taken with a meal; calcium citrate can be taken with or without food. Pills and flavored chews are as effective as food, says Weaver. Pick one with 500 milligrams of either form of calcium and at least 400 I.U. of vitamin D, and space out the doses (one in the morning, one in the afternoon). Or take two antacid tablets a day. One regular-strength Tums contains 500 milligrams of calcium carbonate at about half the cost of a supplement.