Mammary tumor inhibition by IP6: A review

While most studies of diet and breast cancer are focused on the role of fat , very few have addressed the effect of fiber. Emerging epidemiological dat a, and careful review of previous studies point to a negative correlation o f breast cancer with high fiber cereal diets. Inositol hexaphosphate (IP6) is abundant in cereals and legumes, particularly in the bran part of mature seeds. Experimental studies using 7,12-dimethylbenz [a]anthracene (DMBA) a nd N-methylnitrosourea (NMU) in rats and,nice in vivo, as well as human cel l lines in vitro demonstrate a reproducible and striking anti-cancer action of IP6. It therefore appears that IP6 is one of the components, if not the most active ingredient, of high fiber cereal diet responsible far cancer i nhibition. Could eating high fiber diet afford the same protection as IP6? Thus, we investigated whether dietary fiber containing high IP6 shows a dos e-response inhibition of DMBA-induced rat mammary carcinogenesis, and if pu re IP6 is more active as a cancer preventive agent, compared to that ill di et. Our data show that supplemental dietary fiber in the form of bran exhib ited a modest, statistically nonsignificant inhibitory effect. In contrast, animals given IP6 in drink showed significant reduction in tumor number; i ncidence and multiplicity. Therefore, pure IP6 is definitively more effecti ve than a high fiber diet in preventing experimental mammary tumors. Thus, for cancer prevention, prophylactic intake of IP6 may be not only more effe ctive, but also more practical than gorging on large quantities of fiber.