PHYSIOCHEMICAL EFFECTS OF DIETARY FIBER IN HUMANS

饮食与结肠癌之间的关系是复杂的， 脂肪、纤维和能量在其诱导和/或促进中的作用 无疑是相关的。要对它进行分类尤其困难 排除了光纤的作用。在大多数研究中，测试纤维不是 具有特征的或分析的。研究之间的比较也是 因为其他饮食成分之间不一致，所以很难做到。 本申请中提出的研究将比较 物理性质、化学成分和生物效应 三种不同来源的膳食纤维。持续的日常饮食 将被用来控制大多数饮食变量 很难确定纤维的作用。两份，麦麸和燕麦 BRAN，已被选中，因为每个都是相对均一的； 然而，它们具有明显的生理效应，而且 食物中天然纤维来源的代表 供给。根据最近的建议，光纤是 通过使用全食来增加饮食，而不是 浓缩物，第三个纤维源将是由 所有三类含纤维的全脂食品的混合物 食物。每种纤维的物理性能将由以下因素决定 胆汁酸结合、阳离子交换和持水率的测定 体外容量和颗粒大小。可溶和不可溶 将对每种纤维的不同部分进行分析，以获得单独的戊糖 和己糖、糖醛酸、β-葡聚糖和木质素 内容。生物反应是在以下基础上选择的 它们定义结肠环境和/或 结肠微生物区系的代谢活性，包括：粪便 中性和酸性类固醇浓度、成分和 溶解度；微生物质量；纤维消化率；粪便重量；转运 排便时间；排便次数；粪便pH值和氧化还原电位。 选定营养素的表观吸收的测定将是 底物供应进入结肠的间接指示 钙平衡将评估测试的短期安全性 级别。这项研究将建立生物学上的关系 对剂量、化学成分和物理性质的反应 有代表性的纤维来源是健康成年人的先决条件 到开发纤维的治疗用途。调查结果： 拟议的研究将为后续研究提供理由 使用侵入性技术。

The relationship between diet and colon cancer is complex and the roles for fat, fiber and energy in its induction and/or promotion are undoubtedly related. It has been particularly difficult to sort out the role for fiber. In most studies, the test fiber was not characterized or analyzed. Comparisons among studies are also difficult because of inconsistencies among other diet ingredients. The research proposed in this application will compare the physical properties, chemical compositions and biological effects of three different sources of dietary fiber. Constant daily diets will be used to control for most dietary variables that have made it difficult to determine fiber's role. Two, wheat bran and oat bran, have been selected because each is relatively homogeneous; yet, they have distinct physiological effects and are representative of naturally occurring sources of fiber in the food supply. Based on the recent recommendation that fiber be increased in the diet through the use of whole foods, not concentrates, the third fiber source will be that provided by a mixture of whole foods from all 3 classes of fiber-containing foods. The physical properties of each fiber will be determined by measuring bile acid binding, cation exchange and water holding capacities and particle size in vitro. Soluble and insoluble fractions of each fiber will be analyzed for individual pentoses and hexoses by HPLC, uronic acids, beta-glucans and lignin content. Biological responses have been selected on the basis of their potential to define the colonic environment and/or metabolic activity of colonic microflora and include: fecal neutral and acidic steroid concentrations, composition and solubility; microbial mass; fiber digestibility; stool weight; transit time; defecation frequency; fecal pH and redox potential. Determination of apparent absorption of selected nutrients will be an indirect indication of the substrate supply entering the colon and calcium balance will assess the short-term safety of the test levels. This research will establish relationships of biological responses to dose, chemical composition and physical properties of representative fiber sources in healthy adults as a prerequisite to developing therapeutic uses for fiber. Results from the proposed research will form justification for subsequent studies using invasive techniques.