Kidney Bean Protein Prevents High-Fat and High-Fructose Diet-Induced Obesity, Cognitive Impairment, and Disruption of Gut Microbiota Composition

Abstract

A long-term intake of a high-fat and high-fructose diet (HFFD), even a high-fat, high-fructose but low-protein diet (HFFD + LP), could cause obesity associated with cognitive impairments. In the present study, rats were subjected to a normal diet (ND), an HFFD diet, an HFFD + LP diet, and an HFFD with kidney bean protein (KP) diet for 8 weeks to evaluate the effect of KP on HFFD- or HFFD + LP-induced obesity and cognitive impairment. The results demonstrated that compared with the HFFD diet, KP administration significantly decreased the body weight by 7.7% and the serum Angiotensin-Converting Enzyme 2 (ACE-2) and Insulin-like Growth Factor 1 (IGF-1) levels by 14.4% and 46.8%, respectively (p < 0.05). In addition, KP suppressed HFFD-induced cognitive impairment, which was evidenced by 8.7% less time required to pass the water maze test. The 16s RNA analysis of the colonic contents showed that the relative abundance of Bifidobacterium, Butyricimonas, and Alloprevotella was increased by KP by 5.9, 44.2, and 79.2 times. Additionally, KP supplementation primarily affected the choline metabolic pathway in the liver, and the synthesis and functional pathway of neurotransmitters in the brain, thereby improving obesity and cognitive function in rats.

Keywords: cognitive impairment; gut microbiota; kidney bean protein; obesity.

Figure 1

Methodology scheme.

Figure 2

(A) ACE-2; (B) IGF-1; (C) escape latency; and (D) the ratio of swimming distance target quadrant/total distance. Abbreviations: (1) ND, normal diet; (2) HFFD; (3) HFFD + LP; (4) HFFD + KP. Data are expressed as mean ± SD, n = 8, ns = not significant, * p < 0.05.

Figure 3

(A) The Shannon index among groups; (B) the OTU among groups; (C) the gut microbiota at the phylum level among groups; (D) the gut microbiota at the order level; and (E) the relative abundance of Lactobacillus, Bifidobacterium, Butyricimonas, Ruminococcaceae_UCG-005, Lachnospiraceae, Alloprevotella, Enterococcus, and Ruminococcus_torques_group among groups. Data are expressed as mean ± SD, n = 8, ns = not significant, * p < 0.05 compared with HFFD + KP.

Figure 4

(A) Volcano plot for the HFFD + KP group vs. the HFFD + LP group; (B) volcano plot for the HFFD + KP group vs. the HFFD group; (C) bubble plot for the HFFD + KP group vs. the HFFD + LP group; and (D) bubble plot for the HFFD + KP group vs. the HFFD group. Data are expressed as mean ± SD, n = 8.

Figure 5

(A) Volcano plot for the HFFD + KP group vs. the HFFD + LP group; (B) volcano plot for the HFFD + KP group vs. the HFFD group; and (C) the relative content of hypoxanthine, creatine, norvaline, D-alanine, L-histidine, and L-serine among groups. Data are expressed as mean ± SD, n = 8.

Figure 6

The Mantel test results of rat intestinal gut microbiota, brain metabolites, and hepatic lipid metabolites. The size of the square is proportional to the absolute value of the correlation coefficient. The line color and thickness represent the p-value and R value of the Mantel test.