Primary source of dietary protein is correlated with differences in the intestinal microbiome diversity

Abstract

In spite of the recent popularization of the vegan diet, there is currently a deficit of studies that compare the impact and associated health benefits of dietary protein source, one of the main differentiators between vegan and non-vegan diets, on the intestinal microbiome. The objective of this study was therefore to correlate observed changes in the intestinal microbiome to changes in dietary protein sources. We hypothesized that changes in dietary protein source are associated with changes in the composition of the intestinal microbiome. The participant changed their diet over four separate one-week periods to include plant proteins only, plant proteins and dairy proteins, animal proteins only, and finally animal proteins and dairy proteins. The participant followed their respective dietary treatments for one week. Bacterial 16S dual-index sequencing and bioinformatic analysis identified seven genera and two families of bacteria. Of these, Bifidobacterium, Bacteroides, Lactobacillum, and Clostridium exhibited population trends correlated with changes in diet. Moreover, a comparison of α-diversity indicated a statistically significant change over the course of the experiment. Although the results of this experiment cannot be generalized due to the sample size, the hypothesis of this experiment was validated: changes in dietary protein source are correlated with changes in the diversity of the intestinal microbiome. However, we recommend further research into the impacts of variance in dietary protein source on the microbiome, especially by implementing longer-term dietary treatments.