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Research Newsletter-Spring/Summer 2007

LPI 10th ANNIVERSARY COLLOQUIUM

Chlorophylls in the prevention of cancer: From animal models to humans

George Bailey, Ph.D.
Principal Investigator, Linus Pauling Institute;
Distinguished Professor, Oregon State University

The human cancer risk can be substantially lowered by modifying our diet. Many food compounds have been shown to lower cancer risks in animals. However, not many studies have looked at dietary factors and cancer risk in humans.

Our current research is examining the effect of chlorophyll (the green compound found in plants) and chlorophyllin (a water-soluble version of chlorophyll) in reducing cancer risk.

Aflatoxin B1 (AFB1) is a toxin produced by a fungus, which grows on grains and peanuts. AFB1 is known to cause DNA damage in the liver and can lead to liver cancer. AFB1 is a problem in less developed countries and areas where grains are stored in warm, moist areas, which encourages the growth of the fungus that produces AFB1.

In prior animal studies, we found that chlorophyllin reduces the amount of AFB1 that is absorbed in the digestive system, resulting in less AFB1 reaching the liver, less liver DNA damage, and thus less liver cancer. DNA repair systems in our bodies work to remove most of the DNA damage caused by AFB1. The damaged DNA products can be detected in urine.

One in ten adults in the Yangxi delta region of rural China dies of liver cancer. This extraordinary statistic is due to a combination of two risk factors—chronic hepatitis B virus infection and unavoidable dietary intake of AFB1 from moldy corn and other grains. In a large cooperative project, we were able to examine the cancer protective effects of chlorophyllin in humans. We provided a chlorophyllin tablet with each meal to volunteers in the city of Quidong for four months. For those volunteers who received doses of chlorophyllin, we observed a 55% reduction of DNA-damaged products in the urine as compared to those who received a placebo. This suggests that chlorophyllin reduces the amount of AFB1 absorbed from the human digestive system.

To expand upon our findings, we are currently doing a small pilot study on human volunteers who are given very small doses of AFB1, doses equivalent to 5% of what the U.S. FDA allows in one peanut butter sandwich. Using very sensitive analytical equipment, we are able to track AFB1 absorption and elimination from the human body, something that has never been done in people. We are studying the absorption of oral doses of AFB1 alone, AFB1 plus chlorophyll, and AFB1 plus chlorophyllin. Initial results from a single trial showed that chlorophyll reduced the amount of AFB1 absorbed into the blood stream, which suggests that less AFB1 reached the liver. Chlorophyllin also reduced the amount of AFB1 absorption, but to a lesser degree. We have only begun these studies, and the analysis will be completed next year.

Last updated May 2007