Impact of Yogurt and Rolled Oats on the Gut Microbiome: A Randomized Crossover Study displaying Individual Responses and General Resilience

We conducted a randomized controlled intervention study in which 110 healthy participants consumed 250 g of yogurt daily for four weeks in one intervention and 250 g of yogurt combined with 50 g of rolled oats in a second four-week intervention. Metagenomic sequencing and metabolomic analysis were conducted on stool samples, while health markers were assessed in the participants' blood. Here, we observed that yogurt consumption led to a transient increase in the abundance of yogurt bacteria in the gut microbiota of the study population. An additional 50 g of rolled oats caused a temporary slight homogenization of the microbial composition within and between participants which were mainly attributed to a relatively small sub-population with a Prevotella-predominant gut microbiota. No additional effects of yogurt or yogurt and rolled oats consumption on fecal SCFA concentrations and human health markers were identified. Functional analysis of the metagenomic data revealed fluctuations that were mostly attributable to the enrichment of yogurt-derived bacteria after both interventions. A healthy gut microbiota can withstand transient changes in diet without displaying drastic changes in gut microbial composition. The impact of diet is heavily dependent on an individual's baseline microbiome, underscoring the need for personalized dietary recommendations.