Study: Soy Lowers Risk of Endometrial Cancer

Data suggest threat may be reduced by up to 50 percen


A diet rich in soy and other foods containing phytoestrogens can cut a woman's chance of developing endometrial cancer significantly, according to a study of Bay Area women published today in the Journal of the National Cancer Institute.

Interviews with 970 Bay Area African-American, white and Latina wom-en about their diets suggests those who consumed the most foods with phytoestrogens -- natural chemicals regulating plant hormones -- reduced their risk of developing endometrial cancer by 40 percent to 50 percent.

"The most common sources of phytoestrogens in the Bay Area diet include tofu and soy milk, doughnuts when made with soy flour, and perhaps coffee," said Dr. Pamela Horn-Ross, research director at the Union City-based Northern California Can-cer Center and lead author of the study.

Dried apricots, prunes and sunflower seeds also have high amounts of phytoestrogens.

Of the women who participated in the study, 500 were diagnosed with endometrial cancer -- a cancer of the inner lining of the uterus -- between 1996 and 1999. The remaining 470 women had never had the disease.

The risk reduction was most dramatic for postmenopausal women.

Horn-Ross said that because obesity has been found to double a woman's chances of developing endometrial cancer, consumption of foods with phytoestrogens is particularly important for heavy women.

She cautioned, however, that dietary supplements were not part of the study and high concentrations of phytoestrogens can be damaging to the endometrium and breasts.

"By getting your phytoestrogens through a variety of foods as part of a balanced diet, you can avoid these high levels while experiencing the benefits," Horn-Ross said. Endometrial cancer is the fourth most common form of cancer among women in the United States.

About 775 women in the Bay Area and Monterey Bay Area are diagnosed with the disease each year, according to NCCC.

Research suggests that endometrial cancer is related to prolonged exposure to the hormone estrogen without cyclic exposure to the hormone progesterone.

A previous study of women in Hawaii found that eating soy could cut the risk of developing endometrial cancer in half.

Phytoestrogens have long been a source of interest among cancer researchers. This is mostly because Asian populations consume a diet high in soy products and have much lower rates of hormone-dependent cancers than westerners, particularly breast, endometrial, colon and prostate cancers.

Contact Rebecca Vesely at rvesely@angnewspapers.com