THE EFFECT OF TYPES OF DIETARY FIBER ON COLONIC CONSTITU

拟议研究的总体目标是阐明生理化学 各种膳食纤维的性质，然后再进一步考虑 它们可能用于人类癌症预防的临床试验。 具体来说，我们建议研究完整纤维的影响，即小麦 麸皮和燕麦麸皮，以及分离的纤维部分，即纤维素和 果胶，（1）粪便体积和脂肪酸，（2）肠道代谢活性 使用粪便细菌β-葡萄糖醛酸酶和 7 α-脱羟酶活性，（3）粪便胆汁酸和诱变剂，以及（4） 血浆中钙、镁、锌、铜。 约90-100名健康受试者食用高脂肪/低纤维美国饮食 将进行粪便致突变活性筛查。 健康受试者（n=28）， 已显示具有显著水平的粪便致突变活性， 将被选择进行饮食干预研究，并将 在整个研究过程中作为自己的对照。 4周后 基线饮食数据收集，参与者将被要求遵循 规定（补充）膳食纤维水平6周，之后 将再次恢复不含补充纤维的正常基线饮食， 周 4种膳食纤维中的每一种都将遵循这种模式。 将采集每例个体的粪便和血液标本2次 在每个基线饮食期间和2次补充饮食期间 研究中的每种纤维的纤维周期。 粪便和血液样本将 分析上述生化参数。 将对数据进行分析 从统计学上确定各种膳食纤维对 生化参数 这些研究将提供所需的信息 各种膳食纤维对粪便成分的影响， 似乎在结肠癌发生中起作用。

The overall objective of the proposed study is to elucidate physiochemical properties of various dietary fibers prior to further consideration of their possible use in human clinical trials in cancer prevention. Specifically, we propose to study the effect of intact fibers, namely wheat bran and oat bran, and of isolated fiber fractions, namely cellulose and pectin, on (1) fecal bulk and fatty acids, (2) metabolic activity of gut microflora using fecal bacterial Beta-glucuronidase and 7Alpha-dehydroxylase activities, (3) fecal bile acids and mutagens, and (4) Ca, Mg, Zn and Cu in blood plasma. About 90-100 healthy subjects consuming a high-fat/low-fiber American diet will be screened for fecal mutagenic activity. Healthy subjects (n=28) who have shown to have significant level of fecal mutagenic activity from the above screening, will be selected for diet intervention study and will serve as their own controls throughout the study. After 4 weeks of baseline diet data collection, the participants will be asked to follow the prescribed (supplemental) dietary fiber level for 6 weeks, after which normal baseline diet without supplemental fiber will again be resumed for 4 weeks. This pattern will be followed for each of the 4 dietary fibers. Fecal and blood specimens will be collected from each individual 2 times during each baseline diet period and 2 times during supplemental dietary fiber period for each fiber under study. Fecal and blood samples will be analyzed for the above biochemical parameters. The data will be analyzed statistically to determine the effect of various dietary fibers on the biochemical parameters. These studies will provide the needed information on the effect of various dietary fibers on fecal constituents that seemingly play a role in colon carcinogenesis.