A study protocol for a randomised crossover study evaluating the effect of diets differing in carbohydrate quality on ileal content and appetite regulation in healthy humans.
A study protocol for a randomised crossover study evaluating the effect of diets differing in carbohydrate quality on ileal content and appetite regulation in healthy humans.
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DOI：
10.12688/f1000research.17870.2
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发表时间：
2019-01-01
期刊：
影响因子：
--
通讯作者：
Frost, Gary
中科院分区：
文献类型：
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作者：
Byrne, Claire S;Blunt, Dominic;Frost, Gary
引言：从回肠远端到达结肠的肠蠕动的主要成分是碳水化合物。这种碳水化合物易受微生物发酵的影响，可以从根本上改变结肠中的细菌种群及其产生的代谢产物，特别是短链脂肪酸（SCFA）。然而，目前对人类回肠中碳水化合物的形式和水平以及回肠微生物群的组成知之甚少。我们目前对小肠不能吸收的碳水化合物的理解大多来自回肠造口模型，这可能不能反映完整胃肠道的生理学。方法：我们将在健康人群中进行随机交叉研究，研究回肠内容物如何根据饮食变化。受试者将在研究机构住院接受3次单独的4天访视。在每次访视期间，参与者将食用三种碳水化合物质量不同的饮食之一：1）低纤维精制饮食; 2）细胞结构完整的高纤维饮食; 3）细胞结构被破坏的高纤维饮食（例如研磨，混合）。第1天，将鼻肠管置入回肠远端，并在X线透视下确认其位置。将通过鼻肠管收集回肠样品并进行代谢分析，这将确定存在的碳水化合物的量和类型，并将测量回肠微生物群的组成。将采集血液样本以评估循环激素和代谢物。将采集粪便样本以评估粪便微生物群组成。将使用视觉模拟量表收集主观食欲测量值。呼吸氢将被实时测量，作为肠道发酵的标志。最后，将用回肠液接种体外连续发酵模型，以了解不同饮食后结肠中产生的微生物组成和SCFA的变化。注册号：ISRCTN11327221。
Introduction: A major component of the digesta reaching the colon from the distal ileum is carbohydrate. This carbohydrate is subject to microbial fermentation and can radically change bacterial populations in the colon and the metabolites they produce, particularly short-chain fatty acids (SCFA). However, very little is currently known about the forms and levels of carbohydrate in the ileum and the composition of the ileal microbiota in humans. Most of our current understanding of carbohydrate that is not absorbed by the small intestine comes from ileostomy models, which may not reflect the physiology of an intact gastrointestinal tract. Methods: We will investigate how ileal content changes depending on diet using a randomised crossover study in healthy humans. Participants will be inpatients at the research facility for three separate 4-day visits. During each visit, participants will consume one of three diets, which differ in carbohydrate quality: 1) low-fibre refined diet; 2) high-fibre diet with intact cellular structures; 3) high-fibre diet where the cellular structures have been disrupted (e.g. milling, blending). On day 1, a nasoenteric tube will be placed into the distal ileum and its position confirmed under fluoroscopy. Ileal samples will be collected via the nasoenteric tube and metabolically profiled, which will determine the amount and type of carbohydrate present, and the composition of the ileal microbiota will be measured. Blood samples will be collected to assess circulating hormones and metabolites. Stool samples will be collected to assess faecal microbiota composition. Subjective appetite measures will be collected using visual analogue scales. Breath hydrogen will be measured in real-time as a marker of intestinal fermentation. Finally, an in vitro continuous fermentation model will be inoculated with ileal fluid in order to understand the shift in microbial composition and SCFA produced in the colon following the different diets. Registration: ISRCTN11327221.