Dietary copper, manganese and iron affect the formation of aberrant cryptsin colon of rats administered 3,2 '-dimethyl-4-aminobiphenyl

Aberrant crypt foci (ACF) are preneoplastic lesions for colon cancer. Alter ed amounts of copper-zinc (CuZnSOD) and manganese (MnSOD) superoxide clismu tases have been implicated in multistage carcinogesis of both rodents and h umans. Dietary factors are potential modulators of both CuZnSOD and MnSOD a ctivity. The purpose of this study was to investigate the interactive effec ts of dietary copper,manganese, and iron on 3,2'-dimethyl-4-aminobiphenyl ( DMABP)-induced ACF and superoxide dismutase activities in weanling rats fed low or adequate copper (0.8 or 5.1 mu g Cu/g diet), low or adequate mangan ese (0.6 or 17 mu g Mn/g diet), and adequate or high iron (37 or 140 mu g F e/g diet). Twelve rats were allowed free access to each of these eight diet s for 3.5 wk prior to DMABP administration and for an additional 8 wk after the first: DMABP injection. Rats fed low dietary copper had 105% (P < 0.00 01) higher formation of DMABP-induced ACF than those fed adequate dietary c opper. Rats ingesting low rather than adequate dietary manganese had 23% hi gher formation of ACF, and rats ingesting high rather than adequate dietary iron had 18% higher formation of ACF. Heart total superoxide dismutase act ivity was significantly correlated with the number of ACF (r = -0.43, P < 0 .0001) in rats administered DMABP. These results suggest that dietary alter ations that affect superoxide dismutase activity may affect cancer suscepti bility.