Effect of Pea Hull Fiber on Uremic Metabolites and Gut Microbiota Composition in Individuals Undergoing Hemodialysis

Objectives The objective was to determine the effects of pea hull fiber intake on serum uremic molecules and microbiota composition of individuals undergoing hemodialysis. Methods A randomized, double-blind, placebo-control, crossover study was conducted with individuals undergoing hemodialysis. Following a 1-week baseline, participants consumed muffins with added pea hull fiber (15 g/d) and control muffins daily for 4 weeks in random order, separated by a 4-week washout. Blood and stool samples were collected during each period. Serum p-cresol sulfate (PCS), indoxyl sulfate (IS) and trimethylamine N-oxide (TMAO) were analyzed by LC–MS/MS and fecal microbiome profile by 16S rRNA gene amplicon sequencing. qPCR for taxa of interest (Akkermansia muciniphila, Faecalibacterium prausnitzii, Bifidobacterium, and Roseburia) was performed. QIIME 2 sample-classifier was used to discover a unique microbiota profile due to the consumption of pea hull fiber. Results Of the 18 participants randomized (50 ± 4 y; eGFR 6.6 ± 0.7 ml/min/1.73m2), 13 completed the study. No significant changes from baseline were observed in serum PCS (3256 ± 505 μmol/L), IS (166 ± 23 μmol/L) or TMAO (96 ± 12 μmol/L), or for the relative quantification of A. muciniphila, F. prausnitzii, Bifidobacterium, and Roseburia, taxa thought to be health enhancing. Taxa that most distinguished the microbiota composition during the pea hull fiber intervention from usual diet periods were enriched Gemmiger, Collinsella and depleted Lactobacillus, Ruminococcus, Coprococcus and Mogibacteriaceae. Given that abundance of Collinsella has been inversely associated with dietary fiber, this finding was unexpected. Conclusions In dialysis patients, added pea hull fiber did not reduce the serum levels of targeted uremic molecules but did alter fecal microbiota composition. Future research in this patient population should explore the efficacy of alternate fiber sources or plant-based dietary patterns for reducing serum levels of uremic toxins. Funding Sources Saskatchewan Pulse Growers.

Gastrointestinal Tolerance and Microbiome Response to Snacks Fortified with Pea Hull Fiber: A Randomized Trial in Older Adults

ABSTRACT Background Consuming foods with added fiber may help older adults achieve fiber recommendations; however, many high-fiber ingredients have little effect on laxation and may contribute to unpleasant gastrointestinal side effects. Objectives The aim of the study was to determine the effects of consuming snacks fortified with pea hull fiber (PHF) on stool frequency and form, gastrointestinal symptoms, and appetite in older adults. An exploratory aim was to determine if PHF altered the microbiota profile. Methods A 10-wk, randomized, blinded, crossover study was carried out. Following a 2-wk baseline period, participants [aged (mean ± SD) 69.7 ± 6.5 y; n = 31; 14 men, 17 women] consumed snacks providing 10 g/d of PHF or a control, each for 2-wk periods followed by 2-wk washouts. Participants used the Bristol Stool Form Scale (BSFS) to record daily stool frequency and gastrointestinal symptoms, and completed the Gastrointestinal Symptom Rating Scale (GSRS) and Simplified Nutritional Appetite Questionnaire (SNAQ) biweekly. One stool was collected per period for 16S ribosomal RNA high-throughput amplicon sequencing of the fecal microbiota profile. Results Participants reported 1.63 ± 0.05 stools/d and 76.6% normal transit stool form at baseline and no change with PHF. GSRS syndrome scores were similarly unchanged. Daily abdominal noises and bloating were higher for PHF versus control, and flatulence was higher for PHF versus baseline, suggesting fermentation in some individuals. There was no evidence to suggest a common PHF-induced microbiome response for the group as a whole; however, a subgroup of participants (n = 7) who responded with increased flatulence (fermenters), harbored many different taxa than nonfermenters, and demonstrated lower abundance of Clostridiales with PHF. Appetite was unchanged with PHF. Conclusions PHF did not modulate stool form or frequency in older adults with normal bowel habits. Because snacks fortified with PHF did not suppress appetite, PHF may be an appropriate fiber source for older adults at nutritional risk. Microbiome profile may be predictive of gastrointestinal symptom response to PHF. This trial was registered at www.clinicaltrials.gov as NCT02778230.

132 Short-term and long-term intake of high-level pea fiber specifically affects the bacterial community and metabolites in the cecum of pigs

Current study was conducted to investigate the influence of short-term and long-term feeding of high-level pea-hull fiber (PF) on the bacterial community and metabolites in the cecum of pigs. A total of 50 healthy weaned Duroc × Landrace × Yorkshire piglets (7.2 ± 0.5 kg) were selected and randomly allocated in two groups with 5 replicates (5 piglets per replicate) in each group. Pigs in control group were given basal diets. For pigs in another group, expanded corn in the basal diet was replaced by PF at 10%, 20% or 30% for the post-weaning period (from weaning to 30 d post-weaning), growing period (30–90 d post-weaning), and finishing period (90–160 d post-weaning), respectively. At the end of the first and the last period, one pig from each replicate was sacrificed and the cecal digesta was collected immediately. Results showed that: 1) short-term or long-term intake of high-level PF had no significant effect on the ADFI and ADG of the pigs (P > 0.05), but the F/G was significantly decreased in the long-term fed pigs (P < 0.05). 2) The long-term feeding of PF significantly increased the concentration of cecal volatile fatty acids and decreased the ratio of propionate (P < 0.05). 3) Compared with control group, the ratio of phylum Firmicutes in the cecum of piglets with short-term feeding of PF was reduced by 5.6%, with an increase of Bacteroides-Prevotella-Porphyromonas (BPP), Enterococcus, Clostridium cluster IV, Bacteroidetes, Lactobacillus and Desulfovibrio desulfuricans (P < 0.05). While in the cecum of pigs with long-term feeding of PF, the ratio of phylum Bacteroidetes was increased by 4.8%, with an increase of D. desulfuricans (P < 0.01) and a decrease of BPP, Helicobacter-Flexispira-Wollinella, Streptococcus, Enterococcus and Clostridium cluster I (P < 0.05). Results indicate that bacteria in the hindgut of pigs can rapidly response to the high-level PF in the diet.