Common Bean and Chickpea Supplemented Diets Beneficially Enhance the Colonic Microenvironment and Reduce Colitis‐Associated Inflammation
Authors: Power Krista A. , Monk Jennifer M , Lepp Dion , Robinson Lindsay E , Wu Wenqing , Carey Christine , Graf Daniela , Hussain Adeel , McGillis Laurel 
Published: November 2023

Dietary impacts on the colonic microenvironment (microbiota and mucosal barrier) can play an important role in modulating gut‐associated inflammatory diseases, such as inflammatory bowel disease (IBD).Pulses, such as common beans and chickpeas, are rich sources of gut health promoting bioactives, including non‐digestible fermentable carbohydrates and phenolics, however, research demonstrating whole pulse effects on the colonic microenvironment and subsequent inflammatory pathologies, are lacking. Our objectives were to determine the effects of cooked bean and chickpea diets on critical aspects of colon health (microbiota activity and community structure, and colonic epithelial barrier integrity and function) and subsequent effects on disease severity following colitis‐associated mucosal injury. In study 1, male C57Bl/6 mice were fed a 20% cooked black bean flour supplemented diet (BB) or an isocaloric control diet (CON) for 3 weeks, followed by exposure to dextran sodium sulphate (DSS, 2% w/v, 5d) to test the ability of BB to prime the colon and attenuate the severity of colitis‐induced damage mimicking IBD. In study 2, a similar study design was used except mice were fed CON or diet supplemented with 20% cooked chickpeas.Prior to DSS‐exposure (healthy mice; n=10/diet), BB diet increased i) colon crypt height, goblet cell number, and mucus production, ii) mRNA expression of MUC1‐3, RELMβ, REG3γ, IgA, occludin and JAM‐A, and iii) reduced serum LPS levels compared to CON, indicative of enhanced antimicrobial defense and gut barrier integrity. Furthermore, compared to CON, BB consumption i) increased microbial‐derived cecal short chain fatty acids (SCFAs) acetate, butyrate, and propionate, and ii) altered the colonic microbial community structure (increased Prevotellaceae, Porphyromonadaceae, and S24‐7 and reduced Rikenellaceae, Lachnospiraceae, Streptococcaceae, Erysipelotrichaceae, Peptococcaceae, and Peptostreptococcaceae), as measured by fecal 16S rRNA sequencing. During colitis (n=10/diet), BB‐fed mice had increased colonic mRNA expression of microbial‐responsive and epithelial barrier integrity promoting genes (MUC1‐3, RELMβ, and TFF3) and reduced colonic pro‐inflammatory mediator production (IL‐1β, IL‐6, IFN‐γ, and TNF‐α). Similar effects of chickpea supplementation were observed in healthy (enhanced mucosal barrier and microbial activity and altered microbial community structure) and colitic mice (reduced disease severity).In conclusion, pulse supplementation resulted in an improved colonic microenvironment as demonstrated by beneficial changes to the microbial community structure and activity, and increased colonic mucosal barrier integrity. This led to an attenuation of colonic damage following DSS‐induced colitis. Therefore, regular consumption of pulse foods may beneficially prime the colonic microenvironment to better respond to inflammatory insults which can mitigate development and severity of inflammation‐associated colonic diseases.Support or Funding InformationORF; AAFC‐Pulse Canada