Are soybeans healthful or unhealthful
Are soybeans healthful or unhealthful?
Gabe Mirkin, M.D.
All plants contain chemicals that are healthful and chemicals that
can harm us. Fortunately for us, our ancestors learned which plants
are edible and healthful, and taught us to avoid those that are
poisonous. However, if you eat very large amounts of one food, you
can poison yourself, even though reasonable amounts are harmless or
For example, soybeans contain genistein, a weak estrogen that may
help to prevent breast cancer. They contain omega-3 fatty acids that
help prevent heart attacks, and are loaded with fiber that helps to
prevent diabetes. But they also contain small amounts of trypsin
inhibitors that increase risk for pancreatic damage and cancer in
animals. Hemagglutinins in soybeans could cause clots to form and
travel to the lungs. Goitrogens in soybeans block thyroid function
to increase your need for that hormone. Estrogen-like genistein in
soybeans could stimulate immature lobules in breast tissue of
infants to increase risk for breast cancer many years later.
Phytates in soybeans and many other plants can block the absorption
However, you would need to eat very large amounts of soy products to
get any of these negative effects. Enjoy a moderate amount of soy
foods, but do not let health claims lead you to eat huge amounts of
soy to the exclusion of other foods. A healthful diet is a varied
December 10, 2005