July 7, 2000 -- Worried that taking estrogen replacement medication may increase their risk of breast cancer, yet plagued by the hot flashes and other symptoms of menopause, more and more women are turning to "natural" solutions such as estrogen-like products derived from plants. One of these substances -- isoflavone -- may actually be helpful in warding off some health problems associated with aging, but it is too soon to recommend the use of supplements to control menopause symptoms. That's the take-home message from the North American Menopause Society, an organization representing physicians and other health professionals who treat middle-aged women.
The group asked an expert panel to study the use of soy products to determine if they are useful for treating some conditions associated with aging. Sadja Greenwood, MD, MPH, who led the expert panel, tells WebMD that the group agrees that physicians who treat menopausal women should consider recommending that these women add whole foods containing isoflavones, such as tofu, to their diets. Published scientific studies, she says, suggest that soy can actually help control cholesterol and thus may protect against heart attacks.
Greenwood tells WebMD that her group decided to issue the consensus statement because menopausal women are very interested in alternatives to hormone replacement therapy with estrogen. "Natural hormone substitutes" are heavily marketed to women, who in turn are questioning their physicians about the value of these products. Even though many women want to know if soy is a "safe alternative to estrogen, which has been associated with an increased risk for breast cancer," Greenwood says that right now too little is known to offer a definitive answer. Her group is calling for more studies to "once and for all answer the question," she says.
For now, Greenwood's group is stopping short of recommending supplements. "Adding whole foods is not a bad idea and is a healthy choice," she says. "We don't really have sufficient data on the safety or effectiveness of isoflavone supplements to make a recommendation about their use." A good way to add soy to the diet, she says, would be to "substitute calcium fortified soy milk for skim or 1% milk or to try a modified vegetarian diet where every few days one would substitute tofu for other protein sources."
In the consensus statement, which is published in the Journal of the North American Menopause Society, the panel recommends these isoflavone intake amounts:
- 50 mg per day of isoflavone, which can be obtained from 25 g per day of soy protein, for cholesterol control. The experts add that taking this amount may also provide some protection against osteoporosis.
- 40-80 mg per day of isoflavone may have some benefit for hot flashes.
- As little as 10 mg per day of isoflavone may be beneficial in lowering cholesterol, although a specific amount cannot yet be recommended to prevent heart disease.
Because there is a wide variation in the blood levels of isoflavones among individuals who are taking the same amounts of the supplements, there is still some question about how much of the isoflavones are needed to be beneficial.
One physician who is grateful for the new statement is Sandra A. Fryhofer, MD, who has a women's medicine practice in Atlanta. "I think it is an excellent consensus opinion," she tells WebMD. "It goes through the evidence that we have thus far and makes some good recommendations." Fryhofer is president of the American College of Physicians/American Society of Internal Medicine and an associate clinical professor of medicine at Emory University School of Medicine. Although she is a member of the North American Menopause Society, she did not participate in drafting the consensus statement.
"The nation, and particularly women, seem to have a fascination with natural products," Fryhofer says, and women are bringing this fascination to their physicians. According to Fryhofer, many of her patients ask about the use of "natural estrogens."
Fryhofer agrees that the best approach is to "get isoflavones from consuming whole foods. I think this is preferable to using the purified isoflavone products. I just recommend adding a little tofu to the diet because you can mix tofu into just about anything."