Fecal factors which modify the formation of fecal co-mutagens in high- and low-risk population for colon cancer.

Dietary patterns and fecal mutagens of 2 population groups with a distinct risk for colon cancer, high-risk, non-Seventh-Day Adventists and a low-risk, vegetarian Seventh-Day Adventists, in the New York metropolitan area were studied. The diet histories indicate that the intake of protein was identical in the 2 groups; a greater portion coming from meat in non-Seventh-Day Adventists and from vegetables in the Seventh-Day Adventists. The intake of fat was lower in Seventh-Day Adventists. Fecal samples were extracted with dichloromethane, partially purified on silica and assayed for mutagenic activity using the Salmonella/mammalian microsome mutagenicity test. When tested alone, fecal extracts from both groups were non mutagenic in TA98 and TA100 strains. Fecal extracts of non-Seventh-Day Adventists and Seventh-Day Adventists enhanced the mutagenic activity induced by 2-AAF in TA98 and TA100 (co-mutagenic activity). However, non-Seventh-Day Adventists showed a significantly higher co-mutagenic activity in TA98 than did Seventh-Day Adventists.