by Dave Schiller
The latest information about calcium counters the oft-heard advice that in creasing one's intake of the vital element is the way to preserve bone mass and reduce the risk of fractures and osteoporosis. The dairy industry likes to promote its products as the key to strong bones and healthy teeth. Best to take that with a grain of salt - er, make that a serving of cooked dark greens.
In the chemistry of calcium, other substances in food aid its retention by the body and transport to the skeletal structure; still others promote the leaching and excretion of calcium.
Simply consuming more calcium is not enough. In a February Vegetarian Times article, "Calcium Clash" Senior Editor Sharon Bloyd-Peshkin writes, "People eating the most dairy products are ingesting the most calcium but coming out behind in the calcium equation."
A strike against dairy as a calcium source, according to Dr. Anthony Sebastian of the General Clinical Research Center at the University of California-San Francisco, is the high content of sulfur amino acids, which increases the amount of calcium excreted by the body.
Bloyd-Peshkin's Vegetarian Times article quotes Dr. Sebastian and Mark Hegsted, PhD, of Harvard Medical School, who ventures even further to tip a sacred cow: "To assume that osteoporosis is due to calcium deficiency is like assuming that infection is due to penicillin deficiency." Bone quality may not be based simply on mineral content.
The governments of Canada and the United States both recommend an intake of 800 mg. of calcium per day, far exceeding what most other nations advise their citizens. Many physicians advise women to consume 1,000 mg. to 1,500 mg to head off osteoporosis. In a letter to the Toronto Star published May 25, Harold H. Draper of the University of Guelph's Department of Human Biology and Nutritional Science points out these recommendations may have more to do with dairy-minded culture than health science. An indication is that in Japan, "the mean intake is 500 mg to 600 mg and the incidence of hip fractures in women is well below that in Canada."
Non-dairy sources of calcium include grains, tofu make with calcium, beans, broccoli, citrus fruits, collard greens, kale, peas, sea vegetables, sesame seeds, spinach and turnip greens. Plant foods overall are a rich source of potassium bicarbonate, which increases the retention of calcium.
According to Rena Mendelson, professor of nutrition at Ryerson Polytechnic University in Toronto, "a woman would need to drink 2.5 cups of milk or eat three to five cups of [calcium-rich vegetables]" a day to meet 'the day's requirement for calcium'." She is quoted in "Milking the subject of calcium," an article that appeared on April 10 in the Globe and Mail's reader-driven column, "The Middle Kingdom."
The Globe and Mail article and the others cited here are recommended reading for anyone who wants to enter the debate on calcium: how best to get it into the body and keep it there. It is a fertile pasture for debate, and will remain so for some time to come. The facts may cause some meat-eaters to consider adding more plant foods to their diets and convert some lacto-