Cancer Prevention with Berries: Role of Anthocyanins

1. Berries have been part of the human diet for many centuries. They are a rich source of known chemopreventive agents including provitamin A carotenoids, C, E, and folate, calcium and selenium, simple and complex phenols, and phytosterols. 2. It has been found that freeze-dried berries can inhibit cancer development in the esophagus, colon, oral cavity, and mammary gland of rodents. Studies suggest that the most active inhibitory compounds in berries are the anthocyanins, the most abundant flavonoids in berries. 3. Berries function to inhibit carcinogenesis by reducing the growth rate of premalignant cells, inhibiting angiogenesis and inflammation, and stimulating apoptosis, cell differentiation, and cell adhesion. Molecular studies indicate that berries exhibit a genome-wide effect on the expression of genes associated with these different cellular functions. 4. The ability of berries to prevent cancer is likely due to the localized absorption of berry compounds into target tissues. Topical treatment of oral dysplastic lesions with a black raspberry gel for a period of 6 weeks resulted in a reduction in histological grade and restoration of loss of heterozygosity (LOH) in about 50% of the lesions. Consumption of black raspberry powder (60 g/day) in a slurry of water for only 2–4 weeks reduced the Ki-67 cell proliferation index in colon tumors taken at surgery from cancer patients. 5. The protective effects of berries on cancer development at specific sites in animals are impressive; however, there is little evidence that berry consumption leads to significant side effects either in animals or in humans. It seems reasonable to suggest that berries be part of the daily diet, and that in individuals at high risk, the daily consumption of several grams of berry powder could well elicit protection.