Carbohydrate utilization by the gut microbiome determines host health responsiveness to whole grain type and processing methods

Authors

Caroline Smith, University of Nebraska-Lincoln
Mallory J. Suhr Van Haute, University of Nebraska-Lincoln and University of Nebraska at OmahaFollow
Yibo Xian, University of Nebraska-Lincoln
Rafael R. Segura Munoz, University of Nebraska-Lincoln
Sujun Liu, University of Nebraska-Lincoln
Robert J. Schmaltz, University of Nebraska - LincolnFollow
Amanda E. Ramer-Tait, University of Nebraska - LincolnFollow
Devin J. Rose, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

9-13-2022

Citation

C. SMITH ET AL. GUT MICROBES 2022, VOL. 14, NO. 1, e2126275 (20 pages) https://doi.org/10.1080/19490976.2022.2126275

Comments

open access

Abstract

Little is known about how interactions among grain processing, grain type, and carbohydrate utilization (CU) by the microbiome influence the health benefits of whole grains. Therefore, two whole grains – brown rice and whole wheat – and two processing methods – boiling (porridge) and extrusion – were studied for their effects on host metabolic outcomes in mice harboring human microbiomes previously shown in vitro to have high or low CU. Mice carrying either microbiome experienced increases in body weight and glycemia when consuming Western diets supplemented with extruded grains versus porridge. However, mice with the high but not low CU microbiome also gained more weight and fat over time and were less glucose tolerant when consuming extruded grain diets. In high CU microbiome mice, the exacerbated negative health outcomes associated with extrusion were related to altered abundances of Lachnospiraceae and Ruminococcaceae as well as elevated sugar degradation and colonic acetate production. The amplicon sequence variants (ASVs) associated with extruded and porridge diets in this in vivo study were not the same as those identified in our prior in vitro study; however, the predicted functions were highly correlated. In conclusion, mice harboring both high and low CU microbiomes responded to the whole grain diets similarly, except the high CU microbiome mice exhibited exacerbated effects due to excessive acetate production, indicating that CU by the microbiome is linked to host metabolic health outcomes. Our work demonstrates that a greater understanding of food processing effects on the microbiome is necessary for developing foods that promote rather than diminish host health.