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Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/26/2002 Publication Date: 3/1/2003 Citation: Davis, C.D. Low dietary copper increases fecal free radical production and fecal water alkaline phosphatase activity and cytotoxicity in healthy men. J Nutr 133:522-527, 2003. Interpretive Summary: One possible dietary factor that may increase susceptibility to colon cancer is inadequate copper intake. A study was conducted in order to investigate the effects of low and adequate copper intakes on copper nutriture and putative risk factors for colon cancer. Seventeen healthy, nonsmoking men aged 21-52 yr completed a 13 wk controlled feeding study in a randomized cross-over design. The basal diet contained 0.45 mg Cu/10.5 MJ. After a 1 wk equilibration period in which the subjects consumed the basal diet supplemented with 1.0 mg Cu/d, subjects were randomly assigned to receive either the basal diet or the basal diet supplemented with 2 mg Cu/d for 6 wk. After the first dietary period, the subjects immediately crossed over to the other level of Cu for the last 6 wk. Volunteers collected their feces during the equilibration period and during the last 2 wk of the two dietary periods for free radical and fecal water analysis. Low dietary copper significantly increased fecal free radical production and fecal water alkaline phosphatase activity. Both of these are potential risk factors for colon cancer. In contrast to the fecal analysis, hematological indicators of copper status were not significantly affected by the dietary treatments. These results suggest that low dietary copper adversely affects fecal free radical production and fecal water cytotoxicity and alkaline phosphatase activity which are putative risk factors for colon cancer and have practical implications because many of the diets consumed in the United States do not contain the recommended amount of copper. Technical Abstract: Background: One possible dietary factor that may increase susceptibility to colon cancer is inadequate copper intake. Objective: To investigate the effects of low and adequate copper intakes on copper nutriture and putative risk factors for colon cancer susceptibility in healthy men. Design: Seventeen healthy, nonsmoking men aged 21-52 yr completed a 13 wk controlled feeding study in a randomized cross-over design. The basal diet contained 0.45 mg Cu/10.5 MJ. After a 1 wk equilibration period in which the subjects consumed the basal diet supplemented with 1.0 mg Cu/d, subjects were randomly assigned to receive either the basal diet or the basal diet supplemented with 2 mg Cu/d for 6 wk. After the first dietary period, the subjects immediately crossed over to the other level of Cu for the last 6 wk. Volunteers collected their feces during the equilibration period and during the last 2 wk of the two dietary periods for free radical and fecal water analysis. Results: Low dietary copper significantly (p<0.01) increased fecal free radical production and fecal water alkaline phosphatase activity. Low dietary copper significantly (p<0.0001) decreased fecal water copper concentrations but did not affect fecal water volume, pH, iron or zinc concentrations. In contrast to the fecal analysis, hematological indicators of copper status were not significantly affected by the dietary treatments. Conclusion: These results suggest that low dietary copper adversely affects fecal free radical production and fecal water cytotoxicity and alkaline phosphatase activity which are putative risk factors for colon cancer. |
