Date of this Version
Christensen, C.M. 2020. Do Lactic Acid Bacteria in Fermented Foods Persist in the Gastrointestinal Tract: An In Vitro Investigation. Undergraduate Honors Thesis. University of Nebraska-Lincoln.
It is now well established that the gastrointestinal microbiota plays a major role in human health. In particular, researchers are focused on how diet and specific dietary compounds can modulate the gastrointestinal microbiota and repair a dysbiotic state. One such approach is through consuming probiotics, prebiotics, or a diet rich in fermented foods containing live microbes. Fermented foods have long been popular because of their enhanced preservation, safety, organoleptic, functionality, and nutritional properties. These fermented foods can also contain live microorganisms that may play a role in improving gastrointestinal health. However, persistence of these exogenous or allochthonous microorganisms within the GI tract is limited by the absence of ecological niches, colonization resistance, and other host factors, resulting in transient microbiomes. In this research, we examined whether fermented food-derived microbes, using Lactobacillus as a proxy group of organisms, can persist within a simulated in vitro gastrointestinal environment, and if this persistence could be altered by the addition of a prebiotic. We demonstrated that Lactobacillus derived from fermented foods were unable to persist in the in vitro environments and were washed out to negligible levels after the initial 24-hour fermentation. The persistence of Lactobacillus, however, was, under some conditions, enhanced by supplementation of prebiotics.