Alabaster O, Tang Z C, Frost A, Shivapurkar N
Institute for Disease Prevention, George Washington University, Washington, DC 20037.
Cancer Lett. 1993 Nov 30;75(1):53-8. doi: 10.1016/0304-3835(93)90207-p.
In this study we compared the influence of high fat (20% w/w) diets that combine low levels of calcium (0.18% w/w) and low (1% w/w), medium (4% w/w) and high (8% w/w) levels of dietary fiber from wheat bran (WB), with high (8% w/w) levels of dietary fiber from psyllium (PS) alone or in various combinations with WB, on the induction of colon tumors in Fischer-344 rats following exposure to azoxymethane (AOM). The rats were fed the experimental diets for 2 weeks, and then were given two s.c. injections of AOM (15 mg/kg body wt./week). Twenty-three weeks following the first injection of AOM, the incidence of colon tumors in the different dietary groups (12 rats/group) was compared. The results clearly showed that by increasing the dietary fiber concentration of WB from 1 to 8% significantly reduced the number of colon tumors/group. When the influence of 8% dietary fiber from WB on the development of colon tumors was compared with that of PS (WB:PS = 0:100), no significant difference was observed. However, combinations of WB and PS showed a greater protective effect than either WB or PS alone, at comparable levels of dietary fiber. The 50:50 combination of WB and PS showed maximum protection, while 25:75 and 75:25 combinations both produced intermediate effects. None of the diets showed any significant effect on the normal growth of rats. The results indicate that WB and PS fiber alone, and to a greater degree in combination, can offer protection against colon cancer promoted by high fat, low calcium diets. Diets that include wheat bran in combination with psyllium could be an effective means of reducing colon cancer risk in human populations addicted to high risk western diets.
在本研究中，我们比较了高脂肪（20% w/w）饮食的影响，这些饮食结合了低水平的钙（0.18% w/w）以及来自麦麸（WB）的低（1% w/w）、中（4% w/w）和高（8% w/w）水平的膳食纤维，还有单独的来自车前子壳（PS）的高（8% w/w）水平膳食纤维或与WB的各种组合，对暴露于氧化偶氮甲烷（AOM）后的Fischer-344大鼠结肠肿瘤诱导的影响。大鼠接受实验饮食2周，然后皮下注射两次AOM（15 mg/kg体重/周）。在首次注射AOM后的23周，比较了不同饮食组（每组12只大鼠）的结肠肿瘤发生率。结果清楚地表明，将WB的膳食纤维浓度从1%提高到8%可显著减少每组的结肠肿瘤数量。当将来自WB的8%膳食纤维对结肠肿瘤发展的影响与PS（WB:PS = 0:100）的影响进行比较时，未观察到显著差异。然而，在相当的膳食纤维水平下，WB和PS的组合显示出比单独的WB或PS更大的保护作用。WB和PS的50:50组合显示出最大的保护作用，而25:75和75:25组合都产生了中等效果。没有一种饮食对大鼠的正常生长有任何显著影响。结果表明，单独的WB和PS纤维，以及更大程度上的两者组合，可以提供针对高脂肪、低钙饮食促进的结肠癌的保护作用。包含麦麸与车前子壳组合的饮食可能是降低沉迷于高风险西方饮食的人群患结肠癌风险的有效手段。
