Public Release: 

Anticancer ingredient in soy -- new questions

University of Illinois at Chicago

Women at risk for breast cancer are increasingly turning to components of natural soy products as a preventive measure against the disease, but research by a UIC scientist questions the effectiveness of the most popular of these commercially available components, called isoflavones.

In a study to be presented April 3 at the American Association for Cancer Research meeting in San Francisco, Dr. Andreas Constantinou, associate professor in the department of surgical oncology in UIC's College of Medicine and research director of the Functional Foods for Health Program, tested purified isoflavones versus soy protein mixes with and without isoflavones to determine their effectiveness in reducing the incidence and the number of mammary gland tumors in rats.

Although all compounds studied reduced the incidence of tumors, the soy protein mix without isoflavones was the most effective in decreasing the number of tumors.

Dr. Constantinou's work also suggested that, whatever the anti-tumor ingredient that was in the soy mixture, it worked by increasing the production of two detoxification enzymes that eliminate free radicals. Free radicals are especially reactive oxygen species - such as superoxide, hydrogen peroxide and hydroxyl radicals - that can damage cells by reacting with DNA, proteins or lipids.

Studies have shown an inverse relationship between the consumption of soybean products and breast cancer risk in premenopausal women. Moreover, the incidence of the disease is lower in Japan and regions of China, where a large percentage of the daily caloric intake is from soybeans, than in Western industrialized countries, where little or no soy is included in the diet.

While studies of soy have demonstrated an inhibitory effect of soy on mammary tumors, research attempting to identify which component of soy is responsible for the salutary response has had mixed results to date.

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The Functional Foods for Health Program is a joint project of UIC and the University of Illinois at Urbana-Champaign. It conducts multi-disciplinary research to identify foods and other natural products that may reduce the risk of chronic diseases or promote optimal health.

UIC's College of Medicine is the nation's largest medical school. One out of six Illinois doctors is a graduate of the college, as are 70 percent of the minority physicians practicing in Chicago. The college produces more medical school faculty than all but five schools in the country.

With 25,000 students, the University of Illinois at Chicago is the largest and most diverse university in the Chicago area and is one of only 88 national Research I universities. Located just west of Chicago's Loop, UIC is a vital part of the educational, technological, and cultural fabric of the entire metropolitan region.


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