Choosing a calcium supplement

It's an ally in the fight against osteoporosis and, according to the Osteoporosis Society of Canada, women between the ages of 19 and 49 should get 1,000 mg of it each day. Calcium, we're told, helps build strong, healthy bones but sometimes we just don't get enough of it.

Changing your diet offers several ways to increase your calcium intake, according to Dr. Nelson Ferreira, a Toronto-based general practitioner who operates a nutritional lifestyle clinic. "Besides dairy, almonds are a good source of calcium, as are sardines, tofu, and salmon," he says. Leafy greens, such as spinach, broccoli, bok choy, and kale are also good sources.

What are the consequences of calcium deficiency?
Not getting enough calcium can lead to osteopenia, a weakening of the bones, which leads to osteoporosis. Ferreira notes that women who have osteoporosis have an increased risk of hip and back fractures. "Calcium deficiencies may also be linked to hypertension, heart disease and stroke."

For those whose diets lack sufficient calcium, getting the daily amount can be as simple as taking a pill, according to Leslie Beck, a registered dietitian and author of Leslie Beck's 10 Steps To Healthy Eating (Viking Canada, 2002).

Build strong bones from the start
The majority of bone density is achieved between the ages of 8 and 16, says Beck. Then, we reach peak bone mass at about 20, according to the Osteoporosis Society of Canada, and bone density is reduced over the years. But even if you didn't get enough calcium in your youth, that's no reason to scrimp on it today. "Calcium helps slow down density loss," says Beck, "so it's never too late to start taking calcium supplements."

But don't head out to the nearest pharmacy or health food store just yet. There's much to consider before choosing a calcium supplement.

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Which type do you want?
Two common types of calcium pill supplements are: calcium carbonate and calcium citrate. "Calcium carbonate is cheaper," says Beck. "But it is less well-absorbed than calcium citrate."

Because calcium carbonate is insoluble, it relies on stomach acid to be absorbed by the body and should be taken with meals. In contrast, calcium citrate can be taken on an empty stomach, and it's better absorbed.

Would you like some vitamin D with that?
Regardless of which type of calcium supplement you choose, you may want to ensure your pills contain vitamin D -- also known as the "sunshine vitamin" because our bodies produce it when skin is exposed to sunlight. "Vitamin D helps the body absorb more calcium," says Beck. "It's actually in very few foods and since our country is dark [for] about six months of the year, it's hard for us to get enough."

What should you avoid?
If you have an allergy to shellfish, be sure to read the label on your bottle. Some supplements are made with oyster shells and other shellfish.

"You should also avoid supplements that contain bone meal and dolomite," cautions Beck, "as they may contain trace amounts of heavy metals, like lead and mercury."

How much should you take at once?
Your body can only absorb 500 mg of calcium at one time, so if you're taking a few supplements each day to make up the required 1,000 mg, Beck advises to divide your doses throughout the day to improve absorption.

To find out if you're getting enough calcium, check out the Osteoporosis Society of Canada's calcium calculator.

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