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CORVALLIS - Three major research programs at Oregon State University are joining forces under a new five-year, $6.8 million grant from the National Cancer Institute to identify how well some natural dietary compounds can prevent cancer in different animals, humans and even fetuses.

This "program project" is one of a select few funded by this federal agency each year. It will help scientists from OSU's Linus Pauling Institute and the Marine Freshwater Biomedical Sciences Center work more effectively with other programs at the university to scientifically demonstrate the value - or perhaps even risks - of using certain foods or supplements in the fight against cancer in the U.S. and around the world.

Among the compounds of particular interest are chlorophyllin, a derivative of the natural chlorophyll found in green vegetables; the polyphenols found in green or white tea; and indole-3-carbinol, a phytochemical found in many vegetables.

The wide-ranging research efforts will explore the value of these compounds in different forms of cancer, including colon, liver, lung, and stomach cancer. "The National Cancer Institute, OSU Research Office and Linus Pauling Institute are helping us make a major commitment to this collaborative program," said George Bailey, a distinguished professor of environmental and molecular toxicology at OSU. "Cancer chemoprevention is an extremely promising field, and there's enough evidence to support human clinical trials with some compounds right now.

"But there's also a great deal more we need to learn about exactly what some of these compounds do, how they function and what types of people or types of cancer they may be appropriate for," he added.

The other principal investigators in the project are professor Rod Dashwood and professor David Williams, both associated with OSU's Linus Pauling Institute.

One of the projects that has already attracted international interest is Bailey's work with chlorophyllin. In an earlier study done in China that was published in the Proceedings of the National Academy of Sciences, researchers showed that inexpensive daily supplements of chlorophyllin could greatly reduce the DNA damage caused by aflatoxin contamination in the diet. This is a major health problem in some parts of the world, including parts of China where one in 10 adults die from liver cancer. Evidence suggests chlorophyllin supplements could cut that mortality rate by more than half.

Now, in combinations of animal, laboratory and human tests, researchers want to find out how natural chlorophyll acts compared to the supplement chlorophyllin, what mechanisms are involved, and what types of cancer might be affected - among those of interest are liver, colon and smoking-related lung cancer. And they will also explore how different chemopreventive agents would work together, such as chlorophyllin and antioxidants.

In other research, Dashwood's project will examine the cancer preventive effects of green and white tea, both of which appear to lessen the risk of colon, small intestine and stomach cancer in animal studies. Researchers want to know how the polyphenols in certain types of tea work to prevent DNA damage from mutagens, and whether they can also help prevent previously mutated cells from progressing into cancer, especially in the gastrointestinal tract.

"We'll use various animal models for this research, but some of the studies also will be done with human volunteers," Dashwood said. "Using a very powerful research technique called accelerator mass spectrometry - a kind of 'atom counter' - we can actually administer doses of compounds you would find in a single hamburger or a cup of tea and track them throughout the body."

In a third study, Williams will take the study of carcinogens even further, examining their impact on a human fetus.

"We already know that fetuses can be fairly vulnerable to the toxic effects of carcinogens, which can cause cancer or birth defects and may relate to some miscarriages," Williams said. "So the question becomes, can we protect fetuses from chemicals that might cross the placental barrier?"

Williams will study chlorophyllin, both caffeinated and de-caffeinated green tea, and indole-3-carbinol in his studies.

In all of this research, the scientists say they will examine not only the potential benefits of foods and supplements but also possible risks.

"Many people take nutritional supplements with little or no scientific research to show what they will do," Bailey said. "We need to carefully examine both benefits and risks, understand how different phytochemicals may interact with one another, determine which ones provide protection against cancer and which might actually be harmful."

It may even be, the scientists said, that the same compound that has a benefit for an adult may interact quite differently with a fetus, or that people with certain genetic makeup may be more predisposed to cancer than others and could therefore benefit from different nutritional approaches.

The long-term goal of this research, the scientists say, is to provide scientifically credible information about the types of diet, lifestyle changes and supplements that may provide optimal health and protect against disease.