Psychobiotic Diet Study

Both, the impact of diet on the microbiota composition as well as the regulation of the microbiota of brain processes, have been well established in the last decade. Additionally, there has been increasing emphasis on the role of diet in supporting optimal mental health. At the same time, psychobiotic interventions are emerging, salvaging the fact that the microbiota is modifiable by external factors. While probiotic and prebiotic interventions have shown promise as psychobiotic agents, whether whole dietary approaches can exert similar effects is largely understudied. Thus, we investigated the influence of a psychobiotic diet on the microbial profile and function as well as on stress and mood in a healthy human population. Forty five adults were randomized into either following a psychobiotic (n=24) or control (n=21) diet for 4 weeks. Microbiota composition and function was characterized using shotgun sequencing. Stress, mood, overall health and diet were assessed using standardized questionnaires. Metabolic profiling of plasma, urine and fecal samples was performed. Intervention with a psychobiotic diet resulted in reductions of perceived stress and an improvement in sleep quality. Additionally, higher adherence to the psychobiotic diet resulted in stronger decreases in perceived stress. Only subtle microbial compositional and functional changes were observed, but the dietary intervention elicited significant changes in the level of specific lipids in the faeces and urinary tryptophan metabolites. Lastly, microbial volatility was linked to greater changes in perceived stress scores in those on the psychobiotic diet. This data highlights that dietary approaches can be used to reduce stress in a human cohort, which holds promise in reducing the prevalence of stress-associated chronic diseases. However, additional research is warranted to investigate the role of the microbiota. Nevertheless, using healthy diets to positively modulate gut–brain communication holds possibilities for the reduction of stress and stress-associated disorders.