A series of studies from the Cornell-China-Oxford Project on Nutrition, Health and Environment, by nutritional biochemist T. Colin Campbell and his colleagues, conclude that
reducing meat intake reduces the risk of losing bone density. Osteoporosis is a condition, usually associated with aging, in which bone density decreases, making people susceptible to breaks and fractures.
Whether dairy products offer protection from osteoporosis, however, is still undetermined, according to the researchers. If dairy products are consumed in a diet high in animal protein, any potential benefit for increased bone density would be undermined. That's because
animal protein, including that from dairy products, may leach more calcium from the bones than is ingested, said Campbell, professor of nutritional biochemistry at Cornell and director of the Cornell-China-Oxford Project, the most comprehensive project on diet and disease ever conducted.
"This phenomenon could explain why Americans, who ingest much higher levels of calcium, have much higher rates of osteoporosis and hip fractures compared with many Chinese and other Asians who consume few dairy products and ingest low amounts of calcium," Campbell said. Hip fractures in the United States, for example, are approximately five times more frequent than in China.
Analyses of these data suggest that increased levels of animal-based proteins, including protein from dairy products, "almost certainly contribute to a significant loss of bone calcium while vegetable-based diets clearly protect against bone loss," Campbell reported.
"Vegetarians obtain plenty of calcium and appear to have higher rates of bone density, which predispose them to lower rates of osteoporosis," said Campbell
Daily physical exercise helped protect bone health in both pre- and postmenopausal women (OI).
"Although dietary calcium intake is most often the focus of nutritional recommendations for osteoporosis, what's important is the calcium balance, not just calcium intake," Parpia stressed. "This is also another case in which just looking at a single nutrient does not tell the whole story. Rather, you have to consider the entire diet."