Iowa State University

Inside Iowa State
February 5, 1999

Battling cancer through plant research

by Steve Jones

One of the loudest battle cries in cancer prevention is "eat your vegetables."

Studies have linked diets high in vegetables and other plant foods to lower cancer risks. Iowa State's Diane Birt is learning how these plants block the deadly disease.

Birt, who chairs the food science and human nutrition department, is nationally known for her research linking cancer and food. Specifically, she studies which foods cause and prevent cancer.

Birt is part of a growing number of scientists studying dozens of obscure chemicals in common vegetables and fruits, such as broccoli and grapes. These compounds have surprised researchers with their impressive abilities to prevent cancer in laboratory tests.

"About one-third of cancers today can be attributed to diet," Birt said. "Our hope is to define and strengthen dietary recommendations and create strategies to block tumor development."

She says Americans suffer from much higher rates of breast, colon and prostate cancer than people in many regions of the world. Fat- and calorie-laden diets are partly to blame, said Birt, an avid gardener. That's why scientists and nutritionists recommend diets high in vegetables and fruits and low in fats and calories.

Birt's background in nutrition can be traced to her undergraduate days as a home economics major at Whittier College, Whittier, Calif. Early in her studies, Birt took a chemistry course. She loved it. She took more chemistry classes, including the toughest ones, and excelled. When Birt started tutoring chemistry majors, it was suggested she also might want to major in chemistry.

After graduating from Whittier with a double major in home economics and chemistry, she went on to Purdue University, where she earned a Ph.D. with an emphasis in nutritional biochemistry.

Birt came to Iowa State in 1975 as an assistant professor of food and nutrition. A year later she took a research position at the University of Nebraska Medical Center's Eppley Institute for Research in Cancer.

She was in the right place at the right time. America was in the early stages of its "War on Cancer." Scientists suspected that diet could help prevent cancer, but little research had been done.

"There were people trained in cancer and not in nutrition, and there were people trained in nutrition and not in cancer. My timing put me at the forefront of how nutrition affects cancer," Birt said.

With a string of grants from agencies like the National Institutes of Health, National Cancer Institute and American Institute for Cancer Research, Birt's research flourished. Initially she studied the "major nutrients" in foods, including proteins, fats and carbohydrates. Today, her research focus primarily is at the cellular level.

Birt returned to ISU in 1997 after 21 years in Omaha. Colleagues wondered why she would leave a major cancer research center for a land-grant university that does not have a medical college.

"Cancer prevention very much belongs in the land-grant environment because of the emphasis on nutrition, plant sciences and wellness," Birt explained. "Cancer centers are weighted toward treatment. There are good basic sciences at Iowa State for research."

Suzanne Hendrich, an associate dean in the College of Family and Consumer Sciences and a food scientist, says Birt is a leader in her field.

"She's a leader in applying molecular biology techniques to understand the mechanisms of how cancer cells get their energy to function," Hendrich said. "Her work on how diet influences hormones that alter cell growth is pretty unique."

Birt is involved in several studies. In one, she is researching a human hormone, glucocorticoid, that may have cancer-fighting properties. It's believed that certain foods, or the restriction of fats and calories in one's diet, may release the hormone in the body, thus helping prevent cancer.

In another project, she is studying the role of apigenin in colon cancer prevention. Produced in plants, apigenin is a chemical that Birt has shown to prevent skin cancer.

Understanding the disease-fighting properties of plants is the first step. However, to make them more beneficial, the compounds must become part of our everyday diets, Birt said.

"This research could lead to genetically engineered foods that could go a long way toward helping prevent cancer and other diseases," Birt added.

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