Dietary soybean protein ameliorates high-fat diet-induced obesity by modifying the gut microbiota-dependent biotransformation of bile acids

• Published in: PloS one 2018-08, Vol.13 (8), p.e0202083-e0202083
• Main Authors: Watanabe, Keita, Igarashi, Miki, Li, Xuan, Nakatani, Akiho, Miyamoto, Junki, Inaba, Yuka, Sutou, Asuka, Saito, Tsutomu, Sato, Takumi, Tachibana, Nobuhiko, Inoue, Hiroshi, Kimura, Ikuo
• Format: Article
• Language: English
• Subjects: Adipose tissue; Animals; Bile; Bile acids; Bile Acids and Salts - metabolism; Bioaccumulation; Biodiversity; Biology and Life Sciences; Biotransformation; Body fat; Body weight; Body weight gain; Cecum; Diabetes; Diet; Diet, High-Fat - adverse effects; Dietary Supplements; Digestive system; Digestive tract; Excretion; Fatty liver; Gastrointestinal Microbiome - drug effects; Gastrointestinal tract; Gene expression; Genetic transformation; Germfree; Glucagon; Glucagon-like peptide 1; Glucagon-Like Peptide 1 - metabolism; Health aspects; High fat diet; High protein diet; Hyperglycemia; Insulin; Intestinal microflora; Intestinal Mucosa - drug effects; Intestinal Mucosa - metabolism; Intestinal Mucosa - microbiology; Intestine; Lipogenesis; Male; Medical research; Medicine and Health Sciences; Metabolic Networks and Pathways - drug effects; Metabolism; Metagenome; Metagenomics - methods; Mice; Microbiomes; Microbiota; Microbiota (Symbiotic organisms); Nutrition research; Obesity; Obesity - etiology; Obesity - metabolism; Phenotypes; Physiological aspects; Proteins; R&D; Research & development; Research and Analysis Methods; Risk factors; Rodents; Secretion; Soy protein; Soybean Proteins - pharmacology; Soybeans; Transformation; Weight reduction
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0202083

The consumption of soybean protein has well-known favorable metabolic effects (e.g., reduced body weight, body fat, hyperglycemia, insulin resistance, hepatic steatosis, and lipogenesis). These effects of soy protein have been linked to modulation by the gut microbiota; however, the dynamic interplay among these factors remains unclear. Accordingly, we examined the metabolic phenotype, intestinal BA pool, and the gut microbiome of male C57BL/6 mice that were randomized to receive either a regular high-fat diet (HFD) or HFD that contained soybean protein isolate (SPI) in place of dairy protein. The intake of SPI significantly reduced the HFD-induced weight gain and adipose tissue mass accumulation and attenuated hepatic steatosis. Along with an enhancement in the secretion of intestinal Glucagon-like peptide-1 (GLP-1), an enlarged cecal BA pool with an elevated secondary/primary BA ratio was observed in the mice that consumed SPI, while fecal BA excretion remained unaltered. SPI also elicited dramatic changes in the gut microbiome, characterized by an expansion of taxa that may be involved in the biotransformation of BAs. The observed effects were abolished in germ-free (GF) mice, indicating that they were dependent on the microbiota. These findings collectively indicate that the metabolic benefits of SPI under the HFD regime may arise from a microbiota-driven increase in BA transformation and increase in GLP-1 secretion.