Researchers worldwide are discovering a cornucopia of compounds in foods and dietary supplements that show promise for preventing cancer. Here is a summary of research papers on this topic that were presented during a one-day symposium, "Natural Products, Diets and Cancer Prevention," on Sunday, March 25, at the 233rd national meeting of the American Chemical Society.

Black raspberries show promise for preventing cancer of the esophagus, colon

Using animal models (rodents) of cancer development, researchers at Ohio State University showed that animals whose diets were supplemented with black raspberries had a 60 percent reduction in tumors of the esophagus and up to an 80 percent reduction in colon tumors. Clinical trials are now underway to determine whether the berries will prevent the development of esophageal and colon cancer in humans, says study leader Gary D. Stoner, Ph.D., a researcher and professor of internal medicine at the university. 

Blueberries contain chemical that may help prevent colon cancer

A compound found in blueberries shows promise in animal studies of preventing colon cancer, according to a joint study by scientists at Rutgers University and the U.S. Department of Agriculture. The compound, pterostilbene, is a potent antioxidant that could be developed into a pill with the potential for fewer side effects than some commercial drugs that are currently used to prevent the disease, according to study leader Bandaru Reddy, Ph.D., a professor in the Department of Chemical Biology at the university. 

Grape seed compounds may prevent skin cancer by boosting immune system

Chemicals obtained from grape seed extract show promise in animal studies as a way to prevent sunlight-induced skin cancer when used as a dietary supplement, according to researchers at the University of Alabama in Birmingham. In studies using mouse models of ultraviolet-light-induced (non-melanoma) skin cancer, mice that were fed diets supplemented with the grape seed compounds, a group of antioxidants called proanthocyanidins, showed a reduction in tumor number (up to 65 percent fewer) and size (up to 78 percent smaller) in comparison to control animals that did not receive the compounds, the researchers say. The compounds appear to work by inhibiting suppression of the immune system caused by ultraviolet light exposure, says Santosh Katiyar, Ph.D., an associate professor in the university's department of dermatology. 

Compound found in high-fiber foods shows promise against prostate cancer

A dietary component found in most whole grain foods, beans, nuts and other high-fiber items shows promise in animal studies as a potent weapon for preventing prostate cancer. The compound, inositol hexaphosphate (IP6), was fed to animal models of prostate cancer and resulted in up to a 66 percent reduction in tumor size in comparison to control animals that were given water instead, the researchers say. The compound, which is sold in stores as a dietary supplement, adds to a growing number of products -- including lycopene, milk thistle extract, vitamin E and selenium -- that also have shown promise against prostate cancer, says Rajesh Agarwal, Ph.D., a professor in the Department of Pharmaceutical Sciences at the University of Colorado Health Sciences Center in Denver. 

Drinking cloudy apple juice daily may help prevent colon cancer

Researchers in Germany say that drinking two to three glasses of cloudy apple juice (unfiltered) per day may help keep colon cancer at bay. In a ten-week study using a mouse model for colon cancer, animals that were fed either cloudy apple juice or a potent extract of the juice showed a 38 percent and 40 percent reduction (respectively) in benign tumors of the small intestine, an indicator of its potential to fight colon cancer, in comparison to control animals that were given water instead of juice, according to Clarissa Gerhäuser, Ph.D., a researcher with the German Cancer Research Center in Heidelberg. The anticancer effect is likely due to a potent class of antioxidants called procyanidins, the researcher says. A widely publicized recent study by a group of researchers in Poland found that cloudy apple juice also is richer in antioxidants -- up to four times higher -- than clear apple juice.