Differential effects of plant-based flours on metabolic homeostasis and the gut microbiota in high-fat fed rats

Taylor M Martinez; Hallie R Wachsmuth; Rachel K Meyer; Savanna N Weninger; Adelina I Lane; Archana Kangath; Gabriele Schiro; Daniel Laubitz; Jennifer H Stern; Frank A Duca

doi:10.1186/s12986-023-00767-8

Differential effects of plant-based flours on metabolic homeostasis and the gut microbiota in high-fat fed rats

Nutr Metab (Lond). 2023 Oct 19;20(1):44. doi: 10.1186/s12986-023-00767-8.

Authors

Affiliations

¹ Physiological Sciences Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA.
² School of Nutritional Science and Wellness, University of Arizona, Tucson, AZ, USA.
³ School of Animal and Comparative Biomedical Sciences, University of Arizona, ACBS Building, 1117 E Lowell St., Tucson, AZ, 85711, USA.
⁴ The PANDA Core for Genomics and Microbiome Research, Department of Pediatrics, University of Arizona, Tucson, AZ, USA.
⁵ Division of Endocrinology, University of Arizona College of Medicine, Tucson, AZ, USA.
⁶ School of Animal and Comparative Biomedical Sciences, University of Arizona, ACBS Building, 1117 E Lowell St., Tucson, AZ, 85711, USA. faduca@arizona.edu.
⁷ BIO 5 Institute, University of Arizona, Tucson, AZ, USA. faduca@arizona.edu.

^# Contributed equally.

Abstract

Background: The gut microbiome is a salient contributor to the development of obesity, and diet is the greatest modifier of the gut microbiome, which highlights the need to better understand how specific diets alter the gut microbiota to impact metabolic disease. Increased dietary fiber intake shifts the gut microbiome and improves energy and glucose homeostasis. Dietary fibers are found in various plant-based flours which vary in fiber composition. However, the comparative efficacy of specific plant-based flours to improve energy homeostasis and the mechanism by which this occurs is not well characterized.

Methods: In experiment 1, obese rats were fed a high fat diet (HFD) supplemented with four different plant-based flours for 12 weeks. Barley flour (BF), oat bran (OB), wheat bran (WB), and Hi-maize amylose (HMA) were incorporated into the HFD at 5% or 10% total fiber content and were compared to a HFD control. For experiment 2, lean, chow-fed rats were switched to HFD supplemented with 10% WB or BF to determine the preventative efficacy of flour supplementation.

Results: In experiment 1, 10% BF and 10% WB reduced body weight and adiposity gain and increased cecal butyrate. Gut microbiota analysis of WB and BF treated rats revealed increases in relative abundance of SCFA-producing bacteria. 10% WB and BF were also efficacious in preventing HFD-induced obesity; 10% WB and BF decreased body weight and adiposity, improved glucose tolerance, and reduced inflammatory markers and lipogenic enzyme expression in liver and adipose tissue. These effects were accompanied by alterations in the gut microbiota including increased relative abundance of Lactobacillus and LachnospiraceaeUCG001, along with increased portal taurodeoxycholic acid (TDCA) in 10% WB and BF rats compared to HFD rats.

Conclusions: Therapeutic and preventative supplementation with 10%, but not 5%, WB or BF improves metabolic homeostasis, which is possibly due to gut microbiome-induced alterations. Specifically, these effects are proposed to be due to increased concentrations of intestinal butyrate and circulating TDCA.

Keywords: Fiber; Metabolism; Microbiome; Obesity.

Abstract

Grants and funding