Calcium: More than just a bone-builder
Consuming adequate amounts of calcium each day is no doubt right at the top of your priority list, just behind cleaning out the refrigerator and organizing your sock drawer. But beyond strengthening bones, calcium may help your heart and even your waistline―and there are a slew of easy ways to introduce more of it into your diet and reap its rewards. If only sorting out that sock drawer were so simple.
All About Calcium
What it is: The most abundant mineral in your body; women carry about 2½ pounds’ worth. Ninety-nine percent of it is in your bones and teeth; the rest resides in your muscles, tissues, and body fluids. In nature, calcium is the chalky substance found in rocks, such as marble.
What it does: Calcium’s best-known role is that of a bone builder, helping to prevent osteoporosis, a bone-weakening disease that afflicts about 8 million women in the United States, and osteopenia, a precursor to osteoporosis. But its lesser-known benefits are just as important. “It’s used by every cell and tissue in the body,” says Robert Heaney, M.D., a professor of medicine at Creighton University, in Omaha. For example, it helps muscles contract, including those you use consciously (like your biceps) and those you use unconsciously (like your heart). Some research has shown that consuming calcium helps your heart and waistline, too. A 2008 study at the Harvard School of Public Health showed that getting enough calcium may be associated with a lower risk of hypertension in adult women. And researchers at the University of Tennessee, in Knoxville, found that people who get their recommended daily allowance of calcium through dairy products may burn fat faster than people who don’t. What’s more, a new study from the National Institutes of Health suggests that adults with an adequate calcium intake may have a lower risk of colorectal cancer.
How much you need: One thousand to 1,200 milligrams a day for adults. Pregnant women need only 1,000 milligrams, because their bodies are more efficient at absorbing calcium. As you age, your body becomes less adept at absorbing the mineral. So once you reach age 51 or menopause, aim for a minimum of 1,200 milligrams. (Note: Although 2,500 milligrams a day is considered as high as you should go, your body excretes any calcium it can’t use. However, too much may tax the kidneys.)
How much you get: Probably not enough. About 75 percent of American women don’t meet their daily requirement. According to the U.S. Department of Agriculture, the average woman age 20 or over consumes 858 milligrams a day.
The best places to find it: Dairy products. A cup of nonfat milk has 302 milligrams, and a cup of low-fat yogurt has 245 to 415. If you don’t consume much dairy, other foods can help. Three ounces of canned sardines (with bones) in oil packs 324 milligrams, a cup of cooked kale has 94 milligrams, and a cup of raw broccoli has 42 milligrams. Practically speaking, if you have a cup of nonfat milk over cereal at breakfast, a cup of low-fat yogurt as a snack, a spinach salad for lunch, a cup of cooked broccoli with dinner, and half a cup of low-fat ice cream for dessert, you meet your daily requirement.
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.