Poster Topical Area: Nutritional Microbiology
Poster Board Number: 253
Objectives: Diets rich in animal source foods vs. plant-based diets have been shown to have differential effects on the gut microbiome. The objective of this study was to determine the specific effects of a fast food (FF) diet (i.e. burgers and fries) compared with the Mediterranean (Med) diet, which is rich in vegetables, whole grains, olive oil, nuts, and fish, on gut microbiome composition and function.
Methods: 10 healthy subjects (male and female, age 18-30, BMI 18.5-25) participated in a controlled cross-over study in which they consumed a Med diet and FF diet for 4 days each, with a 4-day washout between treatments. Subjects were randomized to treatment order and were provided with all study foods according to Calorie needs. Fasting blood draws and fecal sample were taken before and after each treatment. Fecal DNA was extracted and the 16S V4 region amplified using PCR, followed by sequencing on an Illumina MiSeq, and data processing and analysis using the QIIME pipeline. Plasma metabolites and bile acids were analyzed using LCMS.
Results: Certain microbial genera and species that have been shown previously to be increased in individuals consuming diets rich in animal-source foods, including Bacteroides and Bilophila wadsworthia, were increased in most but not all subjects after the FF diet. On the other hand, fiber-fermenting microbial genera and species, including Lachnospiraceae, Roseburia, and Ruminococcus, increased after the Med diet and/or decreased after the FF diet in most individuals. Bacterially produced metabolite indole-3-lactate and indole-3-propionate, which have been shown to confer beneficial effects on intestinal immune cells, either increased after the Med diet or decreased after the FF diet. In some subjects neither the microbiome composition nor plasma microbial metabolites changed in response to the diets, and in a few changes were in the opposite direction, highlighting individual variability in responsiveness to diet.
Conclusion: Consuming an animal fat rich, low fiber fast food diet vs. a high fiber Mediterranean diet altered human gut microbiome composition and function after just 4 days, in individuals who were responsive to diet. In some individuals either no changes or changes in the opposite direction were observed, underscoring the importance of inter-individual variability.
UC Davis Translational Science Center (CTSC NIH grant # UL1 TR000002)
University of California, Davis, CA