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White kidney bean extract as a nutraceutical: Effects on gut microbiota, alpha-amylase inhibition, and user experiences

Lookup NU author(s): Dr David Houghton, Dr Oliver Shannon, Dr Peter Chater, Dr Matthew WilcoxORCiD, Professor Jeffrey Pearson, Kyle Stanforth, Dr Alasdair Blain, Ruth Jeffers, Ruth Nolan, Dr Christopher StewartORCiD, Fiona Malcomson



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


White kidney bean extract (WKBE) is a nutraceutical often advocated as an anti-obesity agent. The main proposed mechanism for these effects is alpha-amylase inhibition, thereby slowing carbohydrate digestion and absorption. Thus, it is possible that WKBE could impact the gut microbiota and modulate gut health. We investigated the effects of supplementing 20 healthy adults with WKBE for one week in a randomised, placebo-controlled crossover trial on the composition of the gut microbiota, gastrointestinal inflammation (faecal calprotectin), gastrointestinal symptoms, and stool habits. We conducted in vitro experiments and used a gut model system to explore potential inhibition of alpha-amylase. We gained qualitative insight into participant experiences of using WKBE via focus groups. WKBE supplementation decreased the relative abundance of Bacteroidetes and increased that of Firmicutes, however there were no significant differences in post-intervention gut microbiota measurements between the WKBE and Control. There were no significant effects on gastrointestinal inflammation or symptoms related to constipation, or stool consistency or frequency. Our in vitro and gut model system analyses showed no effects of WKBE on alphaamylase activity. Our findings suggest that WKBE may modulate the gut microbiota in healthy adults, however the underlying mechanism is unlikely due to active site inhibition of alphaamylase.

Publication metadata

Author(s): Houghton D, Shannon OM, Chater PI, Wilcox MD, Pearson J, Stanforth K, Jordan C, Avery L, Blain AP, Joel A, Jeffers R, Nolan R, Nelson A, Stewart CJ, Malcomson FC

Publication type: Article

Publication status: Published

Journal: Gut Microbiome

Year: 2023

Volume: 4

Online publication date: 18/06/2023

Acceptance date: 21/05/2023

Date deposited: 23/06/2023

ISSN (electronic): 2632-2897

Publisher: Cambridge University Press


DOI: 10.1017/gmb.2023.5

ePrints DOI: 10.57711/t2pm-bs42


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