Examining the relationship between protein levels and the gut microbiome: a meta-analytical investigation

Abstract

The idea that we are what we eat has been discussed at length and the importance of a balanced diet made up of macronutrients has been taught from an early age. But the underlying mechanisms or effect of macronutrient amounts in particular, dietary protein on gut microbes in a range of species have not been widely investigated. In this study we aimed to investigate the effect of dietary protein on gut microbe biodiversity and relative abundance on a variety of species. We used a systematic meta-analysis approach (following PRISMA guidelines) and meta-analytical and meta regression models (R environment) to investigate three key questions: Do differences in dietary protein content lead to consistent differences in gut microbial diversity (i.e., alpha biodiversity indices)? Do differences in dietary protein content lead to consistent differences in relative abundances of main gut microbial phyla (i.e., Bacteroidetes and Firmicutes)? We found that overall diversity, abundance and F:B ratio was not significantly different with dietary protein content. However, there were weak trends in the predicted direction showing that diversity and abundance were higher when protein levels were low and F:B ratio was more skewed when the diet composition had a relatively low ratio of protein, and this effect was stronger in invertebrate species compared to vertebrate species. The weak effects that I report can be partially attributed to a small study effect and therefore it is recommended that the study is repeated when further studies are available to better understand the role that diet composition, in particular dietary protein, play on gut microbe diversity.

Date of Award	2023
Original language	English
Awarding Institution	Western Sydney University
Supervisor	John Hunt (Supervisor)