Iowa may be known for its corn production, but another state commodity is inching into the limelight – soybeans. Scientists and nutritionists are taking a closer look at soy and the role it can play in people’s diets. ÿ

Products made from soy are more common today than ever before.

“There’s a lot more soy foods out there for consumers to pick from than ten years ago,” said Patricia Murphy, university professor of food science and human nutrition. Murphy has worked on a database of soy foods for the Department of Agriculture. The database is a tool for consumers and researchers that provides information on the soy protein content of specific foods and products.

Manju Reddy, associate professor of food science and human nutrition, is leading a study at Iowa State to see how two servings of soy per day affects health and nutrition in women of childbearing age. Sixty-seven participants will spend the next ten weeks on a specialized diet created by Reddy and her research team. ÿ

Reddy will be specifically examining the iron and zinc levels of the participants during the study.

One group will consume two servings of a soy product per day. One of these servings will be either soy milk or soy yogurt and will be eaten for breakfast. The second serving will be part of an evening meal. Three evening meals a week will be eaten at the ISU Nutrition Wellness Research Center. The other four evening meals will be prepared for participants, but they will eat them at home. The evening meals are typical fare – with a soy twist.

Reddy and her team are preparing common meals such as tacos, pasta and burgers – but soy will replace the protein source, such as beef or chicken, usually found in these dishes. A control group will receive similar meals, but without a soy replacement. Both groups can follow their typical diets, but they must consume the foods assigned them.

“We’ve tried to make [soy] a counterpart,” Reddy said. ÿ

Soy is a controversial supplement because studies have shown contradictory results. ÿ

Some studies have shown that soy may reduce cholesterol. But it may not lower cholesterol levels in all people, especially if a person’s cholesterol isn’t very high to begin with.

“If people start out with a high cholesterol level, you may see a decrease,” Reddy said. ÿ

Soy is also controversial because it contains phytic acid, which inhibits iron and zinc absorption.

Reddy is hoping to show through her study that small amounts of soy in a diet are not harmful. ÿ

“[Our hypothesis is] you can consume two servings of soy a day without negative effects,” Reddy said.

The outcome of the study may have far-reaching consequences for the reputation of soy and its present in the marketplace.

For example, Murphy said when the FDA allowed a health claim to be placed on soy milk, grocery stores increased the shelf space dedicated to soy milk. The health claim indicated that soy proteins help improve cardiovascular health.

Reddy’s study is set to begin Feb. 18, and she is hoping to have it completed by finals week of this semester.

To learn more about soy:

ISU Extension Web site

www.extension.iastate.edu

Food and Drug Administration Web site

www.fda.gov