Pulse Crop Effects on Gut Microbial Populations, Intestinal Function, and Adiposity in a Mouse Model of Dietary Induced Obesity

Authors: MCGINLEY, JOHN - Colorado State University; FITZGERALD, VANESSA - Colorado State University; NEIL, ELISABETH - Colorado State University; OMERIGIC, HEATHER - Colorado State University; HEUBERGER, ADAM - Colorado State University; WEIR, TIFFANY - Colorado State University; McGee, Rebecca; Vandemark, George

Submitted to: Nutrients
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2020
Publication Date: 2/25/2020
Citation: McGinley, J., Fitzgerald, V., Neil, E., Omerigic, H., Heuberger, A., Weir, T., McGee, R.J., Vandemark, G.J. 2020. Pulse crop effects on gut microbial populations, intestinal function, and adiposity in a mouse model of dietary induced obesity. Nutrients. 12(3). Article 593. https://doi.org/10.3390/nu12030593.
DOI: https://doi.org/10.3390/nu12030593

Interpretive Summary: A lack of dietary fiber in human diets has been associated with several diseases including coronary artery disease, obesity, and type 2 diabetes. Our gut system is the home to billions of bacteria that assist with food digestion and part of the role of dietary fiber in preventing these diseases is proposed to be its ability to promote ‘beneficial’ bacteria that confer health benefits. Pulse crops, including peas, lentils, and chickpeas typically have 2–3X the amount of fiber as cereal grains and the diseases noted above are more prevalent in cultures that have a relatively low consumption of pulse crops. The objective of this research was to see if feeding different pulses to mice could promote populations of beneficial bacteria and reduce obesity. We found that mice fed pulse crops had approximately 2-5X more beneficial gut bacteria and 5-8% lower adult body weight than mice fed a high-fat diet. We also found that different pulse crops had a range of effects on gut microbe populations, with beans and peas being much superior to chickpeas and lentils in promoting populations of a specific beneficial bacteria, Akkermansia muciniphila, which is involved in maintaining healthy weight in humans. These results support recent public health recommendations to increase human consumption of foods made using pulse crops.

Technical Abstract: The dietary fiber gap that is present in many countries co-exists with a low intake of grain legumes (pulses) that have 2-3 times more dietary fiber than other foods commonly recommended to increase fiber intake. Given the relationships among dietary fiber, gut health and chronic disease risk, a study was undertaken in a preclinical mouse model for obesity to examine how commonly consumed pulses, i.e., chickpea, common bean, dry pea and lentil, would impact gut microbes, intestinal function, and adiposity. Pulses were fed to C57Bl6 mice at similar levels of protein and fiber. Bacterial count in the cecum was elevated 3-fold by pulse consumption. At the phylum level, a 2.2 to 5-fold increase in Bacteriodetes relative to Firmicutes was observed. For Akkermansia muciniphila, a health beneficial bacterium, differential effects were detected among pulses ranging from no effect to a 49-fold increase. Significant differences among pulses in biomarkers of intestinal function were not observed. Pulses reduced accumulation of lipid in adipose tissue with a greater reduction in the subcutaneous versus visceral depots. Metabolomics analysis indicated 108 metabolites that were highly different among pulse types, and several compounds are hypothesized to influence the microbiome. These results support recent public health recommendations to increase consumption of pulse-based foods for improved health, although all pulses were not equal in their effects.