More Calcium Needed

More Calcium Needed

An old wives' tale reminded Mary Oordt that calcium is essential for strong bones and teeth. "There's a saying that for every baby, you lose a tooth," recalls the managing editor of Lethbridge Living magazine, who began to supplement her diet when she was pregnant. "I felt much better," says Oordt, now 58. "So I kept on - I have taken calcium supplements for more than 30 years." The problem, she notes, is that she never knows if she is taking the right amount. "That's been the frustration since I first got into this." Still, anxious to stave off osteoporosis - a debilitating bone disease caused partly by a loss of calcium - Oordt recently increased her intake to 1,500 mg a day. "As you get older, the bones require more calcium to stay healthy," she says, adding that she could only "guess" at how much more.

Last week, nutritional scientists attempted to eliminate much of the guesswork surrounding calcium and four other substances needed to keep bones and teeth strong and healthy: phosphorus, magnesium, vitamin D and fluoride. Until now, recommended intakes of nutrients were set just high enough to prevent deficiencies. But the new recommendations, proposed by a panel of 30 Canadian and American experts, aim to promote optimal health. There were some surprises. New research shows that, contrary to traditional wisdom, women do not need to drink additional milk during pregnancy because the body naturally rebalances calcium levels. At the same time, almost all other groups - particularly the elderly - are urged to add at least one extra serving of dairy products each day. "It's a major step in the right direction," says Suzanne Hendricks, president of the National Institute of Nutrition.

The new standards attempt to reverse the tendency of older people to drink less milk. Those aged 50 and up are advised to increase dietary calcium to 1,200 mg from 800 mg per day, the equivalent of four eight-ounce glasses of milk. "Previously, the recommended intakes were lower for older people because it was felt they didn't need it for bone growth," explains Stephanie Atkinson, a Canadian representative on the bilateral committee on dietary guidelines. "But studies show you can minimize the loss of bone that may lead to osteoporosis if you have the higher amounts of calcium and vitamin D now recommended."

In another first, the panel set an upper limit on calcium intake. Recent scientific literature, notes Atkinson, indicates that large quantities of nutrients may be harmful. Too much calcium, for instance, may lead to kidney stones and could interfere with absorption of minerals such as zinc and iron.

But most North Americans suffer from a lack of calcium, not an excess. Consumption of dairy products has in fact fallen in recent years, partly - experts say - because of the scare about fat. Surveys indicate that Canadians consume an average of 1.6 servings of dairy products each day, lower than the minimum of two servings a day recommended in Canada's Food Guide. For some, supplements may be the answer, although Atkinson warns that calcium in this form is not as well absorbed as from dairy products. Another solution would be to improve the existing food supply. Current regulations already allow food producers to add calcium to flour and baby cereals in Canada. In the United States, consumers can purchase several calcium-enriched products, including orange juice.

But Margaret Cheney, chief of nutrition evaluation for Health Canada, says that such measures are complex and it may take months to assess the implications of the new recommendations for nutritional standards, labelling and the fortification of food supplies. Cheney points to the panel's recommendation of 600 international units of vitamin D for those aged 70 and over. "You can't get that 600 IU of vitamin D from food in a normal diet," she argues. Milk and margarine, she notes, are already enriched with the vitamin, but if it were added to other foods, "children and younger people who drink more milk than the elderly in the end could be exposed to too much vitamin D."

Dr. Robert Josse, chairman of the scientific advisory board at the Osteoporosis Society of Canada, believes that Health Canada officials may be too cautious. "It is extremely difficult to take too much calcium," argues Josse, noting that his organization has recommended levels similar to the new recommendations since the mid-80s. "How many people drink several litres of milk a day?" he asks. "It is more of a danger to have a population that has too little calcium in their diet." Most experts, it seems, agree that more Canadians should wear a moustache.

Maclean's August 25, 1997