Cranberry juice isn't just for urinary health anymore. According to recent research, the cocktail may fight cancer, too. A study in the Journal of the Science of Food and Agriculture reports that eating cranberries or taking supplements of cranberry extract could stop cancerous tumors from growing or spreading (2006, vol. 86, no. 1).

Researchers at the University of Massachusetts Dartmouth isolated the compounds from North American, mixed-variety cranberries and observed their effect on cancerous tumors. Results showed that a low concentration of cranberry compounds called proanthocyanidins slowed the production of human lung, leukemia, and colon cancer cells in vitro.

Proanthocyanidins join the growing list of cranberry compounds known to inhibit tumor cell growth, including ursolic acid, phenolic acids, and quercetin. Also found in grape seed and pine bark, proanthocyanidins are recognized as powerful antioxidants—up to 50 times more potent than vitamin E and up to 20 times more powerful than vitamin C.

However, cranberries' anticancer properties may not be due solely to antioxidant activity, says Catherine Neto, PhD, the study's lead author, but also to unique functions of the phytochemicals studied. Further studies are needed, she says, to determine how the compounds work and whether cranberries are a viable cancer treatment. "It's too early to know how much of the berry or its extract would be necessary [for cancer therapy]," she says. "But the results are definitely promising."