Plant Estrogens May Reduce Endometrial Cancer Risk

Regular consumption of phytoestrogens, weak estrogens found in plant foods, might reduce the risk of endometrial cancer for some women, according to a report in the August 6th Journal of the National Cancer Institute

NEW YORK (Reuters Health) - Regular consumption of phytoestrogens, weak estrogens found in plant foods, might reduce the risk of endometrial cancer for some women, according to a report in the August 6th Journal of the National Cancer Institute.

Exposure to estrogen without exposure to progesterone is associated with an increased risk of endometrial cancer, the authors explain. Phytoestrogens, found in soy, orange juice and other foods, have been shown to reduce the production of estrogen in the body.

Dr. Pamela L. Horn-Ross from Northern California Cancer Center in Union City, California, and colleagues conducted the first study that measured the intake of specific phytoestrogen compounds and compared this to endometrial cancer risk. The study included 500 women with endometrial cancer and 480 women of the age same and ethnic group who did not have endometrial cancer.

The women with the highest total consumption of two types of phytoestrogens--isoflavones and lignans--had a 41% and 32% reduced risk, respectively, of endometrial cancer, compared with women with the lowest levels of consumption, the authors report.

The reduced endometrial cancer risk was particularly evident among postmenopausal women who consumed high levels of isoflavones and lignans, the researchers note.

Though the number of obese women in the study was small, the results suggest that obese postmenopausal women who consumed the lowest levels of isoflavones or lignans had the highest risk of endometrial cancer.

"Based on these findings and other literature on phytoestrogens, I believe that recommending a balanced diet that includes reasonable amounts of phytoestrogen-rich foods is an appropriate public health message at this time," Dr. Horn-Ross told Reuters Health.

"In my opinion, however, we don't have enough information on phytoestrogen supplements in pill form to make any recommendations in either direction regarding these supplements."

Horn-Ross also cautioned, "There is a lot of variability between people, and benefit (or harm) from a given exposure is unlikely to apply across the board. We are working on furthering our understanding of the relationships between phytoestrogens and cancer risk."

"In the meantime," she concluded, "it appears that soy-based and lignan-rich foods may have beneficial effects in some women, with some evidence that it will be greater in postmenopausal women and overweight/obese women."

SOURCE: Journal of the National Cancer Institute, August 6, 2003.