Rewilding the Human Gut: Reintroduction of the Species Limosilactobacillus Reuteri

The large intestine is home to trillions of microbes, known as the gut microbiome, which perform essential functions, such as digesting food and fighting disease. The diversity of microbes present in our gut microbiome is influenced by lifestyle factors, such as dietary patterns, medication usage, and sanitation practices. Research shows that the diversity of the human gut microbiome decreases as societies undergo industrialization. For example, fecal samples from rural Papua New Guineans contain an additional 50 microbial species, such as Limosilactobacillus reuteri, not found in people living in the United States. What has caused the disappearance of L. reuteri in industrialized countries is currently unknown. However, diet is a major factor influencing the composition of the gut microbiome. Microbiota-accessible carbohydrates (MACs) are indigestible carbohydrates that are a primary source of energy for gut microbes. North Americans consume far less of these carbohydrates (which are contained in foods such as beans, yams, and artichokes) than rural Papua New Guineans. The overall aim of this controlled feeding study is to determine if a strain of L. reuteri isolated from rural Papua New Guinea can be established in the gut of Canadians when taken as a probiotic alongside a non-industrialized-type diet designed to promote its growth. Furthermore, the study will determine: (i) the physiological and immunological effects of both L. reuteri and the non-industrialized-type diet, and (ii) the effects of both L. reuteri and the non-industrialized-type diet on gut microbiome ecology.