By Richard Harkness
Enquirer contributor

Question: What are the best ways to get calcium?

Answer: Calcium is necessary for building bone and preventing the bone-weakening disorder osteoporosis.

OTHER TIPS

• Take calcium supplements two hours apart from the times you drink milk or ingest other dairy foods. Dairy products are high in phosphorus, which can bind to the calcium in supplements and inhibit its absorption. • The body can absorb only so much calcium at a time. Absorption of calcium from supplements is most efficient in doses of 500 mg or less, spread throughout the day as needed. • Vitamin D is required for proper calcium absorption. The adult recommended daily intake of vitamin D is 400 IU in people ages 51 to 70, and 600 IU in those over 70. Foods high in vitamin D include fish liver oils, eggs, butter and fortified milk and cereals. Note that most multivitamin supplements contain 400 IU of vitamin D. • The daily upper-intake levels are 2,500 mg for calcium and 2,000 IU for vitamin D. Stay under these amounts and count both dietary sources and supplements in your total intake.

The recommended daily intake for calcium (from both diet and supplements) is 1,000 mg for adults up to age 50 and 1,200 mg for those over age 50. Post-menopausal women may benefit from 1,500 mg a day, as they are at high risk for bone loss due to the decline in the body's estrogen production.

These amounts refer to "elemental" calcium, just the calcium portion of calcium compounds. The compounds used in calcium supplements include calcium carbonate, calcium citrate, calcium gluconate, calcium lactate and calcium phosphate.

Two of the most commonly used compounds in calcium supplements are calcium carbonate and calcium citrate, which contain about 40 percent and 21 percent of elemental calcium, respectively. To get 1,200 mg of elemental calcium, for instance, you'd need to take 3,000 mg of calcium carbonate or 5,700 mg of calcium citrate. That may translate to taking more or larger pills if you use a calcium citrate supplement.

Realize, though, that you can fulfill part, and perhaps all, of your daily calcium needs from foods. A good dietary source of calcium for most people is skim milk, which contains about 300 mg of elemental calcium per glass (8 ounces). Four glasses provide 1,200 mg of calcium. Skim milk provides slightly more available calcium than milk with higher fat content.

Other foods high in calcium include yogurt, cheese and calcium-fortified juice.

It's generally recommended that calcium supplements, particularly calcium carbonate and calcium phosphate, be taken with meals. That's because food stimulates the release of stomach acid, which increases calcium absorption.

There's another issue to consider, though. Certain dietary fiber constituents can bind to calcium and impair its absorption. These include phytates, which are present in most cereals, wheat bran, unleavened bread, nuts and legumes (e.g., beans), as well as soy foods. Others are oxalic acid (found in rhubarb and spinach) and uronic acid (a common plant fiber component).

It may be a good idea to take calcium supplements two hours apart from meals high in these foods.

E-mail rharkn@aol.com