Researchers study effect of soy protein

Monday, August 26, 2002

Soyfoods was the focus of a two-day conference held recently on the Iowa State University campus.

The conference brought together retailers, manufacturers, growers, dietitians, university researchers and reporters who write about food to discuss soybean breeding and processing, new product development and marketing trends.

Several speakers talked about ongoing research that indicates eating soy products can have a positive effect on human health. It's been three years since the U.S. Food and Drug Administration began allowing soy product labels to make statements about the role of soy in reducing heart disease. Since then, hundreds of new food and beverage products made with soy have been introduced.

In addition to reducing the risk of heart disease, research at Iowa State and elsewhere is showing soy consumption can increase bone density. That's good news for women threatened by osteoporosis.

But what about cancer? Can eating soy products reduce our risk of cancer? That's the question Diane Birt wants to answer.

Birt is chair of the ISU food science and human nutrition department and director of the Center for Designing Foods to Improve Nutrition on the Iowa State campus. She's been studying the role diet plays in cancer development for more than 20 years.

"I'm very excited about research that shows soy can improve bone density and reduce the risk of heart disease," Birt told the soyfoods conference audience. "But everyone wants to get the Big C. Unfortunately, we're not there yet."

Birt outlined a 1979 research project that showed tremendous variation in cancer rates around the world. The lowest cancer rates were found in Japan, China and in a Chinese population in California. "That's when scientists began to look at the Asian diet. But as far as being able to prove that the difference is soy consumption, we're not much further along than we were in 1979," Birt said.

Additional studies have supported the notion that diets high in soy protein translate into lower incidences of cancer. "We like to think soy has some protective components against cancer. But there are a lot of components in soybeans. The key active ingredient hasn't been identified," Birt said. "It's possible that a complex mixture of components in soy foods interact in cancer prevention."

Last year Birt won the American Association for Cancer Research DeWitt S. Goodman Lecture award. It goes annually to someone who has done outstanding work in the fields of nutrition and cancer and cancer prevention.

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