de Kok T M, van Faassen A, Bausch-Goldbohm R A, ten Hoor F, Kleinjans J C
Department of Health Risk Analysis and Toxicology, University of Limburg, Maastricht, The Netherlands.
Cancer Lett. 1992 Feb 14;62(1):11-21. doi: 10.1016/0304-3835(92)90193-y.
Fecapentaenes are strong fecal mutagenic compounds presumably occurring in the majority of Western human individuals, and are possibly essential initiators of colon carcinogenesis. Dietary factors have been shown to influence colorectal cancer risk and to modulate both fecal mutagenicity and fecapentaene concentrations. Therefore, in this study, excretion of fecapentaenes is determined in humans consuming either vegetarian or omnivorous diets. The results show that the most predominant fecapentaene forms are excreted in higher concentrations by vegetarians. Consumption of cereal fiber, calcium and carotene as well as fecal concentrations of iso-lithocholic acid were found to correlate positively with excreted concentrations of one or more fecapentaene analogues. On average, 22% of excreted fecapentaene concentrations was found to be related to nutrient intake in stepwise regression models. Dietary calcium intake was found to be the most significant factor positively correlating with excreted fecapentaene concentrations. Intake of mono-unsaturated fatty acids or fiber from vegetables and fruit could be shown to correlate with fecapentaene excretion to a lesser degree. Despite high fecapentaene concentrations in fecal dichloromethane extracts, only 1 out of 20 samples revealed significant mutagenic activity in Salmonella typhimurium TA 100. Further, aqueous extracts of feces from omnivores appeared to be equally mutagenic as feces from vegetarians and contained non-detectable concentrations of fecapentaenes. It is concluded that dietary factors do affect excreted fecapentaene levels, but only to a relatively minor extent. Since vegetarians at low risk for colorectal cancer excrete higher concentrations of fecapentaenes, it could be hypothesized that relatively increased fecapentaene excretion in combination with antimutagenic compounds in feces represents colon cancer prevention.
粪五烯是一类强效的粪便诱变化合物，可能存在于大多数西方人的体内，并且可能是结肠癌发生的重要起始因素。饮食因素已被证明会影响结直肠癌风险，并调节粪便诱变活性和粪五烯浓度。因此，在本研究中，我们测定了食用素食或杂食的人群中粪五烯的排泄情况。结果表明，素食者排泄的粪五烯主要形式的浓度更高。发现食用谷物纤维、钙和胡萝卜素以及粪中异石胆酸的浓度与一种或多种粪五烯类似物的排泄浓度呈正相关。在逐步回归模型中，平均有22%的粪五烯排泄浓度与营养物质摄入有关。发现膳食钙摄入量是与粪五烯排泄浓度呈正相关的最显著因素。单不饱和脂肪酸或蔬菜和水果中的纤维摄入量与粪五烯排泄的相关性较小。尽管粪便二氯甲烷提取物中粪五烯浓度很高，但20个样本中只有1个在鼠伤寒沙门氏菌TA 100中显示出显著的诱变活性。此外，杂食者粪便的水提取物似乎与素食者粪便具有相同的诱变活性，且粪五烯浓度未检出。研究得出结论，饮食因素确实会影响粪五烯的排泄水平，但程度相对较小。由于患结直肠癌风险较低的素食者排泄的粪五烯浓度较高，因此可以推测，粪五烯排泄相对增加并与粪便中的抗诱变化合物相结合代表了对结肠癌的预防作用。
