RX: A Simple Common Bean
If someone told you that a simple bean grown in Kentucky primarily for animal feed could reduce the risk of heart disease, help prevent cancer, and protect against osteoporosis, you might well be skeptical.
Well, set your skepticism aside. The bean in question is the soybean, and recent news of its powers have now been substantiated by the FDA, which recently approved the claim that soy protein, taken with a low-fat diet, may reduce the risk of heart disease. That claim is based on work published by James Anderson, a College of Medicine professor and endocrinologist at UK, and other researchers in the New England Journal of Medicine in 1995.
Anderson has been researching and promoting the beneficial effects of soy protein for the last five years, and evidence of health benefits keeps piling up. "I think soy foods bring more health benefits to the table than anything we can eat," he says.
Anderson notes that there are six major health benefits of soy foods. For starters, soy reduces the risk of heart attack. LDL cholesterol (the so-called "bad" cholesterol) is a strong predictor for heart attack, and Anderson says that soy protein lowers LDL by 13 percent, which translates to a 20 percent estimated reduction in risk. As Anderson sees it, this is due mainly to a key part of the soy protein: the isoflavones. These plant estrogens act like aspirin in their role as anticoagulants, decreasing clotting in the blood. "I assign about 70 percent of soy health benefits to isoflavones," he says.
The impact of soy protein in reducing the risk of cancer is strongest for prostate cancer, according to Anderson.
There is also some optimistic data for breast cancer, but the jury is still out.
"I recently attended the International Soy Symposium in Washington, D.C. All the experts were there. The data is just not firm enough for us to make public health statements about soy protein and breast cancer," Anderson says.
But there is mounting evidence that soy foods protect us from osteoporosis. "It makes more dense bones," he says, which is good news for women approaching menopause. Another health benefit for these women is that soy protein reduces menopausal symptoms.
Anderson says that only 15 percent of the women whose doctors prescribe hormone replacement therapy actually follow the recommended treatment. And concerns about the side effects from hormones, like breast cancer or blood clotting, prevent many women from choosing this therapy. Anderson believes soy protein may be a good alternative. "I feel comfortable recommending to my patients who can't take estrogens that they take soy isoflavones."
Anderson has conducted research on soy's effect on diabetes since the mid-'70s and is excited by what soy protein does for the kidneys. Anderson says about one-third of all diabetics develop kidney problems, such as "protein leakage."
"This problem is the first definite sign of kidney disease in diabetes," Anderson says. He explains that in diabetics "the blood flow through the kidneys increases to 30 to 50 percent above normal." This increased blood flow damages blood vessels, and protein leaks into the urine. "Our data support the fact that the use of soy protein decreases protein leakage," Anderson says.
For his patients who can benefit from soy protein, Anderson advocates 25 grams a day. He believes soy products won't be hard to find, pointing out that each year since 1995 soy food sales have climbed 20 to 25 percent.