The effects of prolonged fibre exposure on microbiota gastro intestinal function and energy regulation

理论依据：进食速度下降和饱胀感的出现定义为正常饱胀。这些变化在肥胖者中减弱，因此减慢进食速度和增强饱腹感可能是控制体重的有效手段，并且可能通过操纵食物结构来实现。纤维补充剂已被证明可以通过影响餐后饱腹感来降低食欲，但也可能具有有益的餐内作用。然而，虽然有些纤维可以减少能量摄入，但它们对饱腹感的确切影响很少被测试;也没有系统分析引起任何变化的机制。由于其不同的生理化学特性和各种生物行为效应，纤维可能是研究食欲过程的有效工具，以促进饥饿和饱腹感的正常控制的表征。详细研究纤维对饮食和食欲的影响，并开发其各自的特性，可能会促进新的体重控制产品的开发。纤维可能会影响多种因素，影响进食速度，饱腹感和能量摄入。然而，目前的数据是有限的，在测试的纤维的范围和方法和调查结果的不一致。研究集中在（通常是大量的）纤维对餐后饱腹感的影响上，很少强调重要的餐内因素。方法：由于增加膳食量（而不是膳食频率）是过度消费的最重要组成部分，因此特别限制膳食量的食物结构调整可能比仅旨在加强餐间饱腹感的操作更有效。显然需要用标准化的方法对纤维的作用进行更系统的分析，以确定在加入食物时可以使进食率和饱腹感正常化的纤维-使个人能够建立更健康的饮食方式。学生研究纤维对餐内饱腹感的发展和餐后饱腹感的强度的作用。这些实验将采用通用饮食监测装置，用于连续实时测量饮食。材料：该研究将利用不同纤维（抗性淀粉和低聚果糖）的特殊性质，探索其抑制食欲的功效和特定的作用模式（在行为，心理，生理和代谢后果方面）。为了实现这些目标，我们将把纤维作为一种膳食成分，并测量饱腹感和饱腹感的真实的时间变化。这种方法将允许1）直接测量吃饭的特定后果; 2）识别最有效降低食欲的纤维，以及3）通过测量特定生物标志物阐明其时间位点和作用模式。这些研究将对理解饱足感和饱腹感的心理/生物学中介作用，以及开发可能通过防止过度消费来帮助减肥的令人满意的填充食物产生直接影响。结果：我们将确定纤维的最佳食欲抑制剂量，并评估其对以下方面的影响：摄入量;餐内进食，感觉和食欲测量;餐后饱腹感和补偿摄入;食欲相关的胃肠道肽活性（ghrelin，GIP，GLP-1和PYY）;口盲肠运输的特异性标志物（C13/H2）;血糖，胰岛素和FFA;以及结肠发酵和肠道微生物群修饰指数。除了急性实验室研究，我们将评估纤维富集对每种生物标志物的长期（28天）影响。

RATIONALE: Declining eating rate and emergence of fullness over a meal defines normal satiation. These changes are attenuated in the obese, hence slowing eating rate and amplifying fullness may be effective means of weight control, and might be achieved by manipulating food structure. Fibre supplements have been shown to reduce appetite through effects on post-prandial satiety, but may also have beneficial intra-meal actions. However, while some fibres can reduce energy intake, their precise effects on the development of fullness have seldom been tested; nor has there been systematic analysis of the mechanisms whereby any changes are induced. Due to their diverse physio-chemical properties and various bio-behavioural effects, fibres may be effective tools for the study of appetite processes, to advance the characterisation of the normal controls of hunger and satiety. Detailed study of fibre effects on eating and appetite, and exploitation of their individual properties may advance the development of novel weight control products. Fibres may affect a variety of factors to influence eating rate, fullness and energy intake. However, current data are limited in the range of fibres tested and by inconsistencies in method and findings. Research has focused on the effects of (often large quantities of) fibres on post-prandial satiety, with little emphasis on important intra-meal factors. APPROACH: As increased meal size (not meal frequency) is the most important component of over-consumption, modifications to food structure that specifically limit meal size may be more effective than manipulations that aim solely to reinforce inter-meal satiety. There is a clear need for more systematic analyses of fibre action, with standardised methodology, to identify fibres that can normalise eating rates and fullness when incorporated into foods - enabling individuals to establish healthier eating styles. The studentship examines fibre actions on the development of intra-meal satiation and the strength of post-meal satiety. The experiments will incorporate Universal Eating Monitor apparatus for continuous real-time measurement of eating. MATERIALS: The research will exploit the particular properties of different fibres (Resistant Starches and Fructo-oligosaccharides) to explore their appetite suppressant efficacy, and specific modes of action (in terms of behavioural, psychological, physiological and metabolic consequences). To achieve these aims, we will incorporate fibre as a meal ingredient and measure real time changes in satiation and satiety. This method will permit 1) the direct measures of the specific consequences of eating a meal; 2) identify fibres that most effectively reduce appetite, and 3) elucidated their temporal locus and mode of action through measures of specific biomarkers. These studies will have direct implications for both understanding the psychological/biological mediation of satiation and satiety, and the development of satisfying, filling foods that might aid weight loss by the prevention of over-consumption. OUTCOME: We will determine optimal appetite-suppressant doses of fibres, and assess their effects on: intake; intra-meal eating, sensory and appetite measures; post-meal satiety and compensatory intake; appetite-related gastrointestinal peptide activity (ghrelin, GIP, GLP-1 & PYY); specific markers for oro-caecal transit (C13/H2); blood glucose, insulin and FFA; and indices of colonic fermentation and gut microbiota modification. In addition to acute laboratory studies, we will assess the long-term (28 d) impact of fibre enrichment on each biomarker.