Medically reviewed by Onikepe Adegbola, MD, PhD
Diet selection is a primary aspect of human and animal behavior that has many implications from the evolutionary and ecological perspectives. Various dietary nutrients in the body can often influence this diet selection behavior. For as long as living beings have been created, diet selection has played a tremendously important role because it directly affects their health. The gut microbiome, which is made up of trillions of bacteria and other microorganisms, can impact the availability of nutrients in the body and thus can impact diet selection and foraging behavior. The gut microbiome plays a vital role in our health since it influences digestion.
However, previous studies into diet selection behavior have not studied this link or tested the hypothesis of the gut microbiome on this particular behavior. Our particular study aimed to test this hypothesis and uncover the truth.
Methods Carried Out
Our particular study used germ-free mice. These mice were colonized through bacteria from the gut microbiome retrieved from various species of wild rodents with differing foraging behavior. Their differences stemmed from their varying food preferences, nutrient intake, and dietary needs, which in turn impacted the nutritional composition of their diets. In particular, the study selected herbivore, omnivore, and carnivore rodents.
Behavior in terms of foraging behavior and food intake in the mice was then carried out. The results showed that there were varying differences in the behavior of the subgroups of the colonized mice. Specifically, the study showed that there were astounding differences in their carbohydrate selection. For example, it was seen that herbivore-conventionalized mice, who were colonized by herbivore rodents, had a higher protein to carbohydrate ratio (P: C). This means that they selected and consumed more protein than carbohydrates.
Alternatively, both carnivore and omnivore conventional mice that were colonized by omnivore and carnivore rodents, respectively, selected a lower protein to carbohydrates (P: C) ratio. Therefore, they were more likely to pick out and consume carbohydrates compared with proteins.
Results of the Study
The results of this study support the very old belief that tryptophan, which is an essential amino acid, significantly influences voluntary carbohydrate selection. The tryptophan amino acid is responsible for growth in humans and animals. This study revealed a strong association between tryptophan and feeding preference. Perhaps the bacterial genes found in tryptophan may be the main factors influencing voluntary carbohydrate selection.
Additionally, the results showed that the herbivore-conventionalized mice had larger space in their intestines to allow for the fermentation of micronutrients. This shows striking similarities between them and their specific donor species of rodents.
All in all, the interesting and positive results of this study show that there is a significant influence of the gut microbiome on host selection behavior. This is believed to be done by influencing the level of amino acids in their body. As a result, this study also reveals the mechanism by which the gut microbiome influences foraging and host selection behavior.
Trevelline, B. K., & Kohl, K. D. (2022). The gut microbiome influences host diet selection behavior. Proceedings of the National Academy of Sciences of the United States of America, 119(17), e2117537119. https://doi.org/10.1073/pnas.2117537119