For decades, we have known that proper nutrition is essential for human health, but recent studies have demonstrated that variations in composition and operations of the human gut microbiome can influence the host energy metabolic function, host energy expenditure, and ultimately the nutritional value of food. Knowing this, it would be logical to ask how we may be able to further promote our health by improving ecological health of the microbial communities in our gut. Turnbaugh PJ, et al. set out to examine how variations in diet, nutrition, and environmental exposures can impact the human microbial communities in the gut.
To investigate this, researchers transplanted adult human fecal microbiota into C57BL/6J mice raised in germ-free environments. Mice raised in germ-free environments with different microbial communities provide a system for controlling host conditions. Recipient mice were fed a low fat, plant polysaccharide rich diet, or a high fat, high sugar “Western style” diet for a period of three months. Fecal samples were collected and 16S rRNA sequencing was done to identify the microbes and taxa present. Researchers observed a dramatic shift in gut microbial community structure and taxonomic distribution within a single day. Most notably, the mice maintaining a Western diet had an increased number of microbes from the Erysipelotrichi class. Gene expression and metabolic pathways within the microbiome were also altered. Furthermore, mice administrated the Western diet demonstrated increased adiposity.
Though many factors that shape our gut microbiome are beyond our control, this experiment provides evidence that diet may alter the composition and structure of our gut microbiota over short time intervals.