October 14, 1999, WEST LAFAYETTE, Ind.-- An examination of the amount of calcium in strict vegetarian diets that exclude dairy products has found that these diets, known as vegan, lack the calcium needed to prevent osteoporosis later in life.
Vegan diets are not likely to provide enough calcium, the dietary review concluded, even if people avoid salt, protein, caffeine and other substances that increase calcium loss.
Connie Weaver, head of Purdue University's Department of Foods and Nutrition, says she doubts that many people could follow such a strictly limited diet. "A lot of vegetarians include milk in their diets, so getting enough calcium isn't a problem," she says. "But if they give up dairy products, and don't eat calcium-fortified foods, I don't know how they're going to do it."
Weaver, together with William R. Proulx of Appalachian State University and Robert Heaney of Creighton University, examined various foods to determine their levels of calcium, the rate of absorption of calcium from these foods, and how other components such as protein, salt or caffeine influenced the calcium requirements.
The authors concluded, "For most individuals in a Western culture, liberal consumption of dairy products is the easiest approach and is the least restrictive with regard to consumption of protein, salt or caffeine."
The research was published in the September issue of The American Journal of Clinical Nutrition and was funded by the National Institutes of Health.
Weaver said many nondairy foods contain calcium, and many vegan diets substitute vegetables for dairy products. But the amount of calcium in vegetables is very low compared to dairy products, and many of the vegetables also contain substances that block the body's ability to absorb the calcium.
"Broccoli is very well absorbed by the body and contains a good amount of
calcium for a vegetable. But how much broccoli would you have to eat? We did the
math for you," Weaver says.
Contact: Connie Weaver