Boning up: preventing osteoporosis requires more than just calcium. Here's your complete bone health guide

Muscle & Fitness/Hers, May, 2004 by Stacey Colino

But, sorry, being dairy averse isn't a good excuse for shrugging off the recommended amount of calcium when you can also get enough through other food sources. True, it may take a concerted effort to incorporate these other calcium-rich foods into your diet--among them kale, calcium-fortified soymilk and fortified orange juice, canned sardines and salmon--but the fact that they're also chock-full of other nutrients may make it worth the trouble.

Your other (and perhaps easiest) option, of course, is to take a calcium supplement. Which among the multitudes lining store shelves are the best? Supplements that contain calcium carbonate (such as Tums) offer more available calcium per pill but some women find they cause bloating or constipation. "Another option is calcium citrate, such as Citracal, which may be easier on the stomach," says Leslie Bonci, MPH, RD, director of sports nutrition at the University of Pittsburgh Medical Center. Another difference between the two types of calcium is when you have to take them. For best absorption, calcium carbonate should be taken with a meal, while calcium citrate can be taken with or without food. Consumption of either supplement, though, needs to be spaced out during the day. "The body doesn't absorb more than 500 mg of calcium at one time," says Bonci.

It's important to note, too, that calcium isn't the only nutrient essential to bone health. Good calcium absorption, in fact, depends on vitamin D, which increases the uptake of the mineral into the bone. Throughout much of the year, the skin produces plenty of vitamin D when it's exposed to the sun, but this may be a problem during the winter months in sun-deprived parts of the country. At those times and in those places, it's critical to consume at least 400 IU of vitamin a day from fortified foods or to take a multivitamin. (See Recipe for Strong Bones, p. 116, for sources of D and other osteoporosis-preventive nutrients.)

Vitamin K also has a role in bone health. K stimulates the production of osteocalcin, a protein that contributes to bone strength. Another player is vitamin C, which is critical to the production of collagen, the glue that holds bones together. Magnesium assists in bone formation, too, and helps maintain the body's calcium levels. And potassium contributes to the retention of calcium that's already in bones. In fact, research has found that women who consume large amounts of fruits and vegetables tend to have stronger bones than those who don't, largely because produce is rich in magnesium and potassium, among other nutrients.

While you should definitely make sure you're getting enough of these bone helpers, it's also important that you avoid megadosing on them or any other vitamins or minerals--especially vitamin A. "Excessive levels of vitamin A can interfere with calcium metabolism and utilization and increase calcium excretion, which can increase the risk of bone loss," says Bonci. To be on the safe side, limit your intake of vitamin A to 700 mcg.