Phytic acid and minerals: effect on early markers of risk for mammary and colon carcinogenesis.

This study determined the effect of inositol hexaphosphate or phytic acid (PA; 1.2%), Ca (1.5%) and Fe (535 p.p.m.) alone, and PA in combination with Ca or Fe in a high-fat diet (25%) on the labeling (LI) and mitotic (MI) cell proliferation indices, nuclear aberration (NA) and intraductal proliferation (IDP) in the mammary gland, as well as the LI in colonic epithelial cells. Diet supplementation with PA alone caused reductions (P less than 0.05) in the colon LI by 18%, and in the LI and NA in the total mammary gland structures of mice by 29 and 30% respectively. Supplementation with Fe or particularly Ca caused increases in the colon LI and in the mammary LI, MI, NA and IDP but these were reduced by 25-53% (P less than 0.05) in the presence of PA. These results support the hypothesis that PA may reduce the risk for both colon and mammary cancer and its effect is related to its mineral binding ability. Furthermore, significant relationships (P less than 0.01) were observed between the LI and MI or NA in the total structures of the mammary gland. The number of IDPs also related (P less than 0.05) to LI or NA in the terminal end bud structure of the mammary gland, suggesting that highly proliferating mammary cells, particularly in the terminal end bud structure, are of greater risk for nuclear damage and development to IDP. A significant relationship (P less than 0.01) was observed between the cell proliferation in the mammary gland and that in the colon, indicating that both tissues can be influenced similarly by dietary constituents.