Feeding Concord grape juice to laboratory rats led to significant reductions in both mammary tumor mass and the number of tumors per animal.

Concord grape color extract was also found to slow the increase of rat breast cancer cells in related cell culture tests.

Dr. Keith Singletary, Ph.D. the lead author of the study states, "These studies indicate that components in Concord grape juice can inhibit the growth of certain types of breast cancer cells in rats."

Dr. Singletary adds, "And while these findings are preliminary and based on animal-model research, they certainly suggest the need to look more closely at the possible benefits they may eventually offer women."

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Boston, MA, April 12, 2002—Purple grape juice fed to laboratory animals led to significant reductions in both mammary tumor mass and the number of tumors per animal, according to a study presented at a scientific conference co-sponsored by Harvard Medical School. The researchers also found that Concord grape color extract inhibited proliferation of rat mammary cancer cells in related cell culture tests.

"These studies indicate that components in Concord grape juice can inhibit the growth of certain types of breast cancer cells in rats," explains Keith Singletary, Ph.D., Professor of Nutrition, University of Illinois at Urbana-Champaign, and lead author of the study.

In one study, three different concentrations of Concord grape juice were fed to female Sprague-Dawley rats beginning one week after the administration of a mammary carcinogen—a tumor-inducing compound. Rats in the control group also received the carcinogen, but were fed fluids with concentrations of calories, carbohydrates and organic acids similar to those in the juice concentrations. At the end of the study, mammary tumor mass was reduced by 28% to 36% in the groups consuming the two higher juice concentrations, compared to controls.

At the same time, the number of tumors per animal was reduced by 45% to 65%, in the same two groups. Concurrent experiments also confirmed that addition of Concord grape color extract to cultures of breast cancer cells derived from carcinogen-induced rat mammary tumors lead to a significant, dose-dependent inhibition of cell multiplication.

"In addition to our own work, other research has suggest that certain components in grapes, possibly the polyphenols, may have an inhibitory or preventive affect on the growth of breast cancer cells," notes Dr. Singletary. "And while these findings are preliminary and based on animal-model research, they certainly suggest the need to look more closely at the possible benefits they may eventually offer women."

The research was presented at the International Scientific Conference on Complementary, Alternative and Integrative Medical Research, co-sponsored by Harvard Medical School, UCSF Medical School and the Beth Israel Deaconess Medical Center.

Funding was provided by the Illinois Council on Food and Agricultural Research.