Although American women consume tremendous amounts of calcium, their rates of osteoporosis are among the highest in the world. Conversely, Chinese people consume half as much calcium (most of it from plant sources) and have a very low incidence of the bone disease.(33) Medical studies indicate that rather than preventing the disease, milk may actually increase women’s risk of getting osteoporosis. A Harvard Nurses’ Study of more than 77,000 women ages 34 to 59 found that those who consumed two or more glasses of milk per day had higher risks of broken hips and arms than those who drank one glass or less per day.(34) T. Colin Campbell, professor of nutritional biochemistry at Cornell University, said, “The association between the intake of animal protein and fracture rates appears to be as strong as that between cigarette smoking and lung cancer.”(35)
Humans can get all the protein that they need from nuts, seeds, yeast, grains, beans, and other legumes. It’s very difficult not to get enough calories from protein when you eat a healthy diet; protein deficiency (also known as “kwashiorkor”) is very rare in the U.S. and is usually only a problem for people who live in famine-stricken countries.(36) Eating too much animal protein has been linked to the development of endometrial, pancreatic, and prostate cancer.(37,38,39) Consuming too much protein may also put a strain on the kidneys, causing them to compensate by leaching calcium from the bones.