Hot flashes and other symptoms of menopause can be enough to drive many women crazy. One woman, who reported having as many as 15 intense hot flash episodes each day, said she could not sleep or function, and needed help. Knowing that hormone therapy might not be safe, she did what many women have started to do -- she added soy to her diet.

Conventional medicine promoted the use of hormone therapy for menopausal women, but studies have linked it to a higher risk of heart disease, stroke, blood clots and breast cancer. Those who try to avoid medications and opt for more natural remedies, like soy, need to consider moderation, experts say. Experts say women have reported that soy's high level of phytoestrogens and plant-based estrogens offer hot flash relief. However, some research suggests soy could do more harm than good, particularly for menopausal women.

The main issue: Does consuming large amounts of soy increase or decrease a woman's risk of breast cancer?

The biggest concern is for women who are at high risk for breast cancer, who have an undetected breast cancer or who are survivors at risk for recurrence. Are they exposing themselves to estrogen that might promote certain breast cancers? A related concern is that soy supplements may somehow interfere with tamoxifen, an antiestrogen drug taken by women to help prevent breast cancer.

Experts want to find the connection, if any, between breast cancer and the estrogen in soy. Unfortunately, the effect of the estrogen in soy on breast cells is poorly understood.

Enter conflicting studies performed by different doctors, who also are university professors.

One study suggests that estrogen in soy can cause breast cell proliferation, which may potentially lead to tumor growth.

• Researchers fed isoflavones, like those found in soy supplements, to mice.

• Results indicate that their tumors grew more aggressively with the treatment.

• However, because mice's ovaries were removed, they had almost no estrogen -- even less than a postmenopausal woman would have.

• Without the body's normal estrogen competing for receptor sites on breast cells, the isoflavones' estrogen (genistein) latched onto the sites, causing the tumors to grow.

Another study suggests the estrogen in soy is weak -- and works like breast cancer drugs -- to prevent tumors.

• Using mice with ovaries, researchers fed them isoflavones.

• Results indicate that because of normal estrogen competing with genistein, less estrogen attached to the receptor sites. In this case tumors did not grow.

• However, the mice in this model had more natural estrogen than postmenopausal women.

Neither study used subjects that perfectly mimic the chemistry of postmenopausal women. Meanwhile, no study using women has shown an increased risk of breast cancer among those taking soy.

Wilmington Star-News August 24, 2004