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Inhibition of fried meat-induced rectal DNA damage and altered systemic genotoxicity in humans by crucifera, chlorophyllin, and yogurt
Citation:
Shaughnessy, D. T., D. M. Umbach, B. MacIntosh, M. G. Knize, P. Matthews, A. E. Swank, R. S. Sandler, D. M. DEMARINI, AND J. A. Taylor. Inhibition of fried meat-induced rectal DNA damage and altered systemic genotoxicity in humans by crucifera, chlorophyllin, and yogurt. PLOS ONE . Public Library of Science, San Francisco, CA, 6(4):1-11, (2011).
Impact/Purpose:
To our knowledge, this is the first demonstration that dietary factors can reduce DNA damage in the target tissue of fried-meat associated carcinogenesis.
Description:
Dietary exposures implicated as reducing or causing risk for colorectal cancer may reduce or cause DNA damage in colon tissue; however, no one has assessed this hypothesis directly in humans. Thus, we enrolled 16 healthy volunteers in a 4-week controlled feeding study where 8 subjects ate diets containing meat cooked at either low (lOO°C) or high temperature (250°C), each for 2 weeks in a crossover design. The other 8 subjects also were in a crossover design eating either the high-temperature meat diet alone or in combination with 3 putative mutagen inhibitors: cruciferous vegetables, yogurt, and chlorophyllin tablets. We used the Salmonella assay to analyze the meat, blood, urine, and feces for mutagenicity, and the comet assay to analyze rectal biopsies and peripheral blood lymphocytes for DNA damage. Low-temperature meat had undetectable levels ofheterocyclic amines (HCAs) and was not mutagenic, whereas high-temperature meat had high HCA levels and was highly mutagenic. The high-temperature meat diet increased the mutagenicity of hydrolyzed urine and feces compared to the low-temperature meat diet. The mutagenicity of hydro lyzed urine was increased nearly two fold by the inhibitor diet, indicating that the inhibitors enhanced conjugation. Inhibitors decreased significantly the mutagenicity of un-hydrolyzed and hydrolyzed feces. The diets did not alter the levels of DNA damage in non-target white blood cells, but the inhibitor diet decreased nearly twofold the DNA damage in target colorectal cells. To our knowledge, this is the first demonstration that dietary factors can reduce DNA damage in the target tissue of fried-meat associated carcinogenesis.
