Variability in the health effects of dietary fiber might arise from inter-individual differences in the gut microbiota’s ability to ferment these substrates into beneficial metabolites. Our understanding of what drives this individuality is vastly incomplete and will require an ecological perspective as microbiomes function as complex inter-connected communities. Here, we performed a parallel two-arm, exploratory randomized controlled trial in 31 adults with overweight and class-I obesity to characterize the effects of long-chain, complex arabinoxylan (n = 15) at high supplementation doses (female: 25 g/day; male: 35 g/day) on gut microbiota composition and short-chain fatty acid production as compared to microcrystalline cellulose (n = 16, non-fermentable control), and integrated the findings using an ecological framework. Arabinoxylan resulted in a global shift in fecal bacterial community composition, reduced α-diversity, and the promotion of specific taxa, including operational taxonomic units related to Bifidobacterium longum, Blautia obeum, and Prevotella copri. Arabinoxylan further increased fecal propionate concentrations (p = 0.012, Friedman’s test), an effect that showed two distinct groupings of temporal responses in participants. The two groups showed differences in compositional shifts of the microbiota (p ≤ 0.025, PERMANOVA), and multiple linear regression (MLR) analyses revealed that the propionate response was predictable through shifts and, to a lesser degree, baseline composition of the microbiota. Principal components (PCs) derived from community data were better predictors in MLR models as compared to single taxa, indicating that arabinoxylan fermentation is the result of multi-species interactions within microbiomes. This study showed that long-chain arabinoxylan modulates both microbiota composition and the output of health-relevant SCFAs, providing information for a more targeted application of this fiber. Variation in propionate production was linked to both compositional shifts and baseline composition, with PCs derived from shifts of the global microbial community showing the strongest associations. These findings constitute a proof-of-concept for the merit of an ecological framework that considers features of the wider gut microbial community for the prediction of metabolic outcomes of dietary fiber fermentation. This provides a basis to personalize the use of dietary fiber in nutritional application and to stratify human populations by relevant gut microbiota features to account for the inconsistent health effects in human intervention studies. Clinicaltrials.gov, NCT02322112 , registered on July 3, 2015.

中文翻译：

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成人超重和肥胖的长链玉米糠阿拉伯木聚糖对肠道菌群的调节作用与粪便中丙酸的个体时间增加有关。

肠道微生物群将这些底物发酵成有益代谢物的能力之间的个体差异可能导致膳食纤维对健康的影响发生变化。我们对导致这种个性的因素的理解还很不完整，需要生态学的观点，因为微生物群落起着复杂的相互联系的社区的作用。在这里，我们对31名超重和I级肥胖的成年人进行了一项平行的两臂，探索性随机对照试验，以研究高剂量（女性：25 g / g）的长链复合阿拉伯木聚糖（n = 15）的作用。天；雄性：35 g /天），与微晶纤维素（n = 16，不可发酵的对照）相比，肠道菌群的组成和短链脂肪酸的产生，并利用生态学框架整合了研究结果。阿拉伯木聚糖导致粪便细菌群落组成的全球转移，减少的α多样性并促进了特定分类群的发展，包括与长双歧杆菌，黑叶盲肠和普氏杆菌相关的操作分类单位。阿拉伯木聚糖进一步提高了粪便中丙酸的浓度（p = 0.012，Friedman检验），这种作用在参与者中显示出两种截然不同的时间响应分组。两组显示出微生物群组成变化的差异（p≤0.025，PERMANOVA），多元线性回归（MLR）分析表明，丙酸酯响应是可通过变化而预测的，而在较小程度上则是微生物群的基线组成。与单一类群相比，从社区数据中得出的主要成分（PC）在MLR模型中是更好的预测指标，这表明阿拉伯木聚糖发酵是微生物群内多种物种相互作用的结果。这项研究表明，长链阿拉伯木聚糖可调节微生物群组成和健康相关的SCFA的输出，从而为该纤维的更有针对性的应用提供信息。丙酸生产的变化与组成变化和基线组成都相关，而源自全球微生物群落变化的PC显示出最强的关联。这些发现构成了生态框架价值的概念证明，该生态框架考虑了更广泛的肠道微生物群落的特征，以预测膳食纤维发酵的代谢结果。这提供了个性化膳食纤维在营养应用中的使用以及通过相关肠道菌群特征对人群进行分类的基础，以解释人类干预研究中不一致的健康影响。Clinicaltrials.gov，NCT02322112，于2015年7月3日注册。