Prebiotic mechanisms of resistant starches from dietary beans and pulses on gut microbiome and metabolic health in a humanized murine model of aging

Authors: KADYAN, SAURABH - Florida State University; PARK, GWONCHEOL - Florida State University; SINGH, PRASHANT - Florida State University; ARJMANDI, BAHRAM - Florida State University; NAGPAL, RAVINDER - Florida State University

Submitted to: Frontiers in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2023
Publication Date: 2/7/2023
Citation: Kadyan, S., Park, G., Singh, P., Arjmandi, B., Nagpal, R. 2023. Prebiotic mechanisms of resistant starches from dietary beans and pulses on gut microbiome and metabolic health in a humanized murine model of aging. Frontiers in Nutrition. 10. Article 1106463. https://doi.org/10.3389/fnut.2023.1106463.
DOI: https://doi.org/10.3389/fnut.2023.1106463

Interpretive Summary: Aging is a predestined process of the human lifecycle, which is usually accompanied by a gradual decline in physiological, neurocognitive, and metabolic functions. Emerging evidence is now pointing toward the role of a healthy gut microbiome in aging-associated health. Dietary pulses, being a rich source of fiber and proteins, offer an ideal and inexpensive food choice for older adults to promote gut and metabolic health. However, the prebiotic effects of dietary pulses-derived resistant starches, compared to resistant starches from cereals and tubers, remain relatively underexplored. In this study, we investigated the prebiotic effects of resistant starches derived from pulses (pinto beans, black-eyed peas, lentils, or chickpeas) on the gut microbiome and intestinal health in aged mice whose guts were colonized with human microbiota. Our results showed that dietary pulse-derived resistant starch can beneficially modulate the gut microbiome and induce a reduction in gut leakiness and inflammation. These findings demonstrate that resistant starch supplementation, derived from pulses, should be considered as a potential prebiotic ingredient in functional foods and nutritional applications for to promote the health elderly populations.

Technical Abstract: Dietary pulses, being a rich source of fiber and proteins, offer an ideal and inexpensive food choice for older adults to promote gut and metabolic health. However, the prebiotic effects of dietary pulses-derived resistant starches (RS), compared to RS from cereals and tubers, remain relatively underexplored, particularly in context to their gut modulatory potential in old age. We herein investigate the prebiotic effects of pulses-derived RS on the gut microbiome and intestinal health in aged (60-week old) mice colonized with human microbiota. C57B6/J mice were fed for 20 weeks with either a western-style high-fat diet (control; CTL) or CTL diet supplemented (5% w/w) with RS from pinto beans (PTB), black-eyed-peas (BEP), lentils (LEN), chickpeas (CKP), or inulin (INU; reference control). We find that the RS supplementation modulates gut microbiome in a sex-dependent manner. For instance, CKP enriched a-diversity only in females, while ß-diversity deviated for both sexes. Further, different RS groups exhibited distinct microbiome differences at bacterial phyla and genera levels. Notably, LEN fostered Firmicutes and depleted Proteobacteria abundance, whereas Bacteroidota was promoted by CKP and INU. Genus Dubosiella increased dominantly in males for all groups except PTB, whilst Faecalibaculum decreased in females by CKP and INU groups. Linear discriminant analysis effect size (LEfSe) and correlational analyzes reveal RS-mediated upregulation of key bacterial genera associated with short-chain fatty acids (butyrate) production and suppression of specific pathobionts. Subsequent machine-learning analysis validate decreased abundance of notorious genera, namely, Enterococcus, Odoribacter, Desulfovibrio, Alistipes and Erysipelatoclostridium among RS groups. CKP and LEN groups partly protected males against post-prandial glycemia. Importantly, RS ameliorated high-fat diet-induced gut hyperpermeability and enhanced expression of tight-junction proteins (claudin-1 and claudin-4), which were more pronounced for LEN. In addition, IL10 upregulation was more prominent for LEN, while TNF-a was downregulated by LEN, CKP, and INU. Together, these findings demonstrate that RS supplementation beneficially modulates the gut microbiome with a reduction in gut leakiness and inflammation, indicating their prebiotic potential for functional food and nutritional applications.