In this review, the term psychobiotics was defined as pre- and probiotics that stimulate the growth and/or activity of indigenous beneficial intestinal bacteria, which can improve brain function.
Summary | According to a systematic review published in Nutrients, there is limited evidence available that support the use of pre- and probiotic supplements to positively influence anxiety, stress and cognitive outcomes in between the ages of 6 and 25. The review observed inconsistencies in study findings and, as this could be due to the heterogeneity in study design, recommended three points for improvement for future studies: specificity of the sample, specificity of the intervention and homogeneity in assessment tools applied.
The review by Basso et al included 17 studies that explored the effects of psychobiotics on anxiety and stress. Eleven of the 17 studies administered either a single probiotic species or combinations. The probiotics were administered in different formats (capsules, powders or sachets), different doses and varying durations. The other 6 studies administered prebiotics such as galacto-oligosaccharides and fructo-oligosaccharides. In the studies, a variety of tools were used to assess anxiety and stress. Additionally, there were considerable variations in terms of study populations, with different ages and clinical diagnosis.
A total of 19 studies on the effects of psychobiotics on cognitive outcomes were also included in the review.
The authors concluded that half the studies exploring the use of psychobiotics to improve cognitive function had encouraging results. However, the same limitation of heterogeneity applies to these studies. There were variations in study designs, sample populations and intervention protocols.
On basis of the findings, the authors recommended streamlining three areas for future research. First, the study population. Examples are clinical diagnosis, gender and age. Second, the intervention itself. For instance, the dose of psychobiotics and duration of intervention. Third, the assessment tools used to measure anxiety, stress and cognitive function.
Table 1 shows a summary of the recommendations
Basso M, et al. A systematic review of psychobiotic interventions in children and adolescents to enhance cognitive functioning and emotional behavior. Nutrients 2022;14:614. https://doi.org/10.3390/nu14030614