Procedural schematic. Endoscopic lavage samples were collected from the cecum and sigmoid colon of each subject. The microbial and metabolic components of each sample were analyzed using Illumina-HiSeq 2000 and ultra performance liquid chromatography (UPLC)-mass spectrometry (MS), respectively. The analytic pipeline thereafter is shown. See methods for additional details. OTU: operational taxonomic unit; PICRUSt, phylotypic investigation of communities by reconstruction of unobserved states; HUMAnN: HMP unified metabolic analysis network; PCA, Principal Component Analysis.