New research sheds light on the impact of a protein-rich diet on the gut microbiome and overall health. Despite increased protein intake in Western diets, especially among athletes and obese individuals, the fate of undigested protein and its impact on human health remains largely unknown. A new study published in ASM Microbe investigates whether excess undigested protein in the colon ferments to produce beneficial metabolites such as short-chain fatty acids (SCFAs) or leads to the production of harmful metabolites such as ammonia and sulfides that are associated with gastrointestinal disorders and other health problems.
The research team conducted a series of experiments on mice and found that switching to a high-protein diet significantly reduced body weight, reduced body fat, and induced immediate changes in the gut microbiome. The study also compared diets containing different proteins to examine the effects of individual amino acids on the composition and activity of the gut microbiome. In particular, mice that consumed proteins rich in aromatic amino acids experienced the greatest reduction in body weight and fat mass compared to mice that consumed standard proteins or proteins rich in branched-chain amino acids.
“These findings provide an important foundation for understanding how a protein diet affects the gut microbiome and pave the way for further investigation into the role of diet in promoting gut health and overall health.”
Samson Adejumo, PhD candidate in biology at the University of Illinois at Chicago
To learn more about how amino acids from a protein-rich diet affect gut bacteria, the team conducted a four-week study in 16 mice. The mice were fed a standard diet for two weeks, followed by two weeks of a diet rich in isonitrogenous proteins rich in branched-chain or aromatic amino acids. Daily fecal samples and weekly body composition measurements were collected to monitor changes in fat and lean mass. DNA was extracted from the feces and sequenced to analyze microbial composition and dynamics over the course of the study.
Comparing microbial composition across the four protein groups revealed significantly different abundance and composition of microbial taxa after protein fortification. Using machine learning techniques, the researchers predicted protein diets based on gut microbial taxa with 97% accuracy, supporting the relationship between diet and microbiome changes.
Overall, gut bacterial genera responded differently to the dietary change from a normal carbohydrate diet to a protein diet and, more importantly, to the different amino acid groups. The largest changes occurred in the group receiving branched-chain amino acids. Although it is too early to say for certain that the protein diet caused all the observed changes in body composition and gut bacteria, the consistent pattern of changes strongly suggests an association between the protein diet and changes in the gut microbiota.
The research was led by Adejumo of the Marcel Lab at the University of Illinois at Chicago and supported by the UIC Hampton Marcel Lab Startup Fund, and was presented at ASM Microbe 2024 in Atlanta, Georgia on June 15, 2024.
sauce:
American Society for Microbiology
