Estrogen Found In Soy Stimulates Human Breast Cancer Cells In Mice.

2001 NOV 22 - (NewsRx.com & NewsRx.net) -- The increasingly consumed isoflavone genistein - a plant estrogen linked to the health benefits of soy - has been shown in a series of University of Illinois studies to stimulate the growth of estrogen-dependent human breast-cancer cells implanted into laboratory mice.

The findings of three studies, funded by the National Institutes of Health, are detailed in the Journal of Nutrition (November, 2001), Carcinogenesis (October 2001), and Cancer Research (July 2001).

The results demonstrate that genistein in various forms stimulates tumor growth. They also suggest that women with estrogen-dependent breast cancer or a predisposition to it may want to reduce their consumption of soy products with a high isoflavone content, said William G. Helferich, a UI professor of food science and human nutrition. Many soy isoflavone-containing products are marketed to women over age 50 for the relief of menopausal symptoms.

"Our preclinical laboratory animal data suggest that caution is warranted regarding the use of soy supplements high in isoflavones for women with breast cancer, particularly if they are menopausal," said Helferich, who was the principal researcher on the papers.

For most people, soy is a healthy food and can be used as part of a healthy diet, he said. Isolated soy protein had been found in previous UI studies to effectively lower cholesterol. ...