According to data from a University of Massachusetts study, proanthocyanidins, or PACs, found in cranberries inhibit the growth of lung tumors and colon and leukemia cells in vitro.

Cranberry PACs contain a unique A-type structure, while most other fruit contains only the more-common B-type PACs.

Catherine C. Neto, Ph.D., Associate Professor, Department of Chemistry and Biochemistry at the University of Massachusetts Dartmouth says, "While previous studies have shown that cranberry extracts inhibit the proliferation of cancer cells, this is the first study to confirm that it's the cranberry PACs that are the active components."

Cranberry PACs have a unique "anti-adhesion" mechanism known to protect the body from the harmful E. coli bacteria that cause UTIs.