Gut Bugs: Can We Change Them With Diet?

GUT BUGS AND THEIR INFLUENCE ON HEALTH & DISEASE

The intestinal microbiota include bacteria, fungi, and viruses. The genes expressed by the intestinal microbiota are the microbiome which plays a role in both host health and disease. Commensal microbes (i.e. symbionts) promote host health while pathogenic microbes (i.e. pathobionts) are opportunistic organisms that can harm host health. In health, these two populations of microbes are in homeostasis. The gastrointestinal microbiome is actively involved with the normal physiology of the host organism. This includes energy homeostasis, metabolism, gut health, immune function, and development.¹ The predominant bacterial phylum in the healthy dog and cat is Firmicutes followed by Bacteroidetes in the dog and Actinobacteria in the cat.² The composition of the microbiome can also vary depending on the location in the gastrointestinal tract.

The gastrointestinal microbiome can be influenced by diet, disease, medical intervention (e.g. antibiotic administration), and the environment. Changes to the intestinal microbiome that adversely affects host health are termed dysbiosis. This includes when the population of pathogens overwhelm commensal microbes or the absence of important commensals. Critical illness, for example, is associated with dysbiosis which can occur early during illness and hospitalization. Dysbiosis in this setting occurs through a variety of mechanisms including perfusion injury, antibiotic usage, gastrointestinal dysmotility, physiologic stress, and inadequate enteral nutrition. This dysbiosis may result in infectious complications and negative ...