Menopause

Many psychological changes that take place during menopause are related to a decrease in estrogen production. These include difficulty in regulating body temperature, which can result in "night sweats" and "hot flashes." However, the experiences vary among women throughout the world. For example, in the Japanese language there is no word for the symptom we call "hot flash." In general, Japanese women are much less likely to experience symptoms of menopause at all. Of course, cultural differences may affect how often women are willing to report menopause symptoms. But diet may also play a role.

The weak estrogen-like activity of the isoflavones in soyfoods - which are commonly consumed in Japan - may help to decrease the symptoms of menopause. Australian researchers found that women who ate 1/2 cup of soy flour daily experienced a significant reduction in their menopause symptoms.

Breast Cancer

Breast cancer is the second most common cause of death among American women and is the leading cause of death in women between the ages of 35 and 44. It is a complex disease and scientists don't yet understand exactly what causes it, but they do know that lifestyle affects risk. For example, both alcohol and smoking raise the risk for breast cancer. Certain dietary changes may lower that risk.

Breast cancer rates vary dramatically among different groups of women. American women are four times more likely to die of breast cancer than Japanese women. Although there are a number of possible reasons for this difference, one reason may be that Japanese women consume soy foods. Some research shows that women who eat soy have less breast cancer than those who don't. As little as one serving of soyfoods a day (1/2 cup tofu or 1 cup soymilk) may be enough to reduce risk.

Breast cancer is an "estrogen dependent" cancer. When estrogen attaches to sites on the breast tissue, it can induce the cancer process. Isoflavones look like estrogen so they can attach to the same sites on breast tissue. By occupying these sites, they may keep the more powerful estrogen from exerting its cancer-causing effects. One interesting suggestion is that soy isoflavones act in a way similar to the drug tamoxifen, which is widely used to treat breast cancer. Researchers need to gather much more data before they can say with any certainty that soy will lower breast cancer risk. But for now, it looks like adding some soyfoods to the diet might be a good idea for all women.

Eating more soyfoods isn't a guarantee against disease. Many findings about soy health are speculative. But evidence that soy can positively impact women's health is growing. Adding soy to the diet is easy and pleasant and may reduce risk for a number of diseases.

This information was prepared by Mark Messina, PhD, and Virginia Messina, MPH, RD, authors of The Simple Soybean and Your Health.