Grant: Discovery Grants Program - Individual

Current evidence indicates essential roles for gut microbes in host health through effects on host defense and the immune system, and probiotics receive much attention in this regard. However, attempts to effectively translate and apply current knowledge about probiotics through strategic use of diet and administration modalities have generated controversy, due to variation in effects and outcomes. Such variation poses a challenge to effectively harnessing the potential of probiotics. Gaps in current knowledge about behavior of probiotics in the gastrointestinal (GI) tract must be addressed to meet this challenge. The objective of this research program is to determine how key elements in the GI tract influence the activity of probiotics and their resultant impact on the immune system. The GI tract is a complex milieu with many factors potentially contributing to variation in probiotic efficacy. One fundamental question is how the pre-existing GI tract community of microbes influence the activity of probiotics, a factor that could contribute greatly to variation in response between individuals. Food components with the ability to influence cell signaling and gene expression provide another element that could influence probiotic efficacy in the GI tract. Dairy and soy foods used to deliver probiotics in the diet contain several such components, such as certain vitamins, fatty acids, peptides, and in the case of soy, phytochemicals. This research will determine the impact of these GI tract elements including, variation in the gut microbial community, on the ability of probiotics to act on the immune system. Examining the mechanisms underlying this relationship at the level of cell activity, signalling and gene expression will clarify probiotic effects and lead to new insight into the best ways to utilize probiotics.