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Stories for Reprint
Soy May Offer Safe, Easy Way to Guard Bone Health
By Katerina Pesheva
The nutritional virtues of soy have been extolled, ignored and questioned for years. While most of the medical attention has been focused on soy's cholesterol-lowering qualities, there is something to be said about its effects on bone health as well.
Soy may play a particularly important bone-protective role in post-menopausal women, who are more prone to developing osteoporosis and bone loss as result of hormonal changes.
Soy drew much attention as a natural remedy for women going through menopause after a series of studies found that hormone-replacement therapy might increase one's risk of heart disease, stroke and several types of cancers.
But how much do we really know about the soy-bone health connection?
"As of today, clinical trials have shown mixed responses," explains Rose Catanzaro, a registered dietitian at St. Louis University who works with ob/gyn patients. "Thus the bone-protective effects of soy are still inconclusive and need to be substantiated through longer clinical studies."
However several studies have shown that isoflavones, soy proteins related to estrogen production, may help ward off bone loss caused by loss of estrogen in menopausal women. While most studies to date indicate that soy may help prevent bone loss, it does not appear to increase bone formation.
Despite the mixed evidence, Catanzaro says that women over 50 who are not on hormone replacement therapy should benefit from adding soy to their diets. Women on hormone replacement therapy do not derive any addition al benefits from adding soy to their diets, Catanzaro says.
Because of soy's effect on estrogen, women with history of certain hormone-related cancers, such as certain breast cancers, should avoid too much soy and consult a physician.
"It was once thought that women with a history of estrogen receptor-positive breast cancer should avoid soy products while other studies have shown protective benefits with the use of soy to help prevent breast cancer," Catanzaro says. "There is strong conflicting data regarding both, therefore, as with most things, moderation of intake is prudent."
So how much soy is good for you?
No one has established the right amount yet, Catanzaro says. Some researchers have found bone-protective effects with as little as 40 mg of soy per day.
Catanzaro recommends consuming soy from food sources, such as beans and soymilk, as opposed to food supplements sold in stores. The Food and Drug Administration does not regulate food supplements, therefore the amount of active ingredients in such supplements may vary widely, Catanzaro warns.
In addition to helping maintain healthy estrogen levels, soybeans are also rich sources of calcium. The following equal one cup of milk in terms of calcium content:
One and a half cups of cooked soybeans
Half cup of tofu with calcium
Two and a half cups of broccoli
Four cups of pinto beans
Five cups of red beans
Two cups of white beans
About 1.5 million bone fractures a year in the United States are attributed to osteoporosis. Half million of them require hospitalization. Studies show that annual direct care expenditures for osteoporotic fractures range from $12 to $18 billion per year, according the U. S. Surgeon General's Office.
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