Background: Research indicates that probiotics, specific strains of beneficial bacteria, are beneficial against anxiety and depression. There are indications that a potential mechanism behind this...Show moreBackground: Research indicates that probiotics, specific strains of beneficial bacteria, are beneficial against anxiety and depression. There are indications that a potential mechanism behind this might be that probiotics alter interoception and the way we respond to our body needs, which is reflected in interoception. Both critically influence anxiety and depression. Objective: The present study aimed to test whether administering probiotics over a period of four weeks increases the degree of interoception and adaptive responding to body needs in healthy individuals. Also, anxiety and depression were measured. Confirming an increase in the degree of interoception and adaptive responding would show that probiotics trigger a mechanism that reduces anxiety and depression. Design: The study was set up as a randomized, tripleblinded, placebo-controlled within/between subject (placebo versus probiotics), pre- and postintervention assessment design. 89 healthy participants without diagnosed mood or anxiety disorders, aged 18-35 years, received multispecies (diverse strains) probiotics or placebo supplementation over four weeks. In the pre- and post-intervention, degree of interoceptive awareness, adaptive responses, depression, and anxiety. Results: There were no significant changes on any measure, but one unexpected decrease in adaptive responding for the probiotics group. Conclusion: It cannot be concluded that probiotics increase the degree of interoceptive awareness and adaptive responding. Moreover, the results suggest that anxiety and depression are not influenced by probiotics in a healthy sample. However, insights from other research suggests that the effect might be stronger in a depressed and anxious sample. Further research is needed to see whether probiotics might affect interoception and adaptive responding differently in depressed and anxious individuals.Show less
According to the WHO, depression is one of the major causes of disability worldwide. However, the understanding of the disorder remains incomplete. Recently, antibiotic use has been associated with...Show moreAccording to the WHO, depression is one of the major causes of disability worldwide. However, the understanding of the disorder remains incomplete. Recently, antibiotic use has been associated with the onset of mood disorders. It is assumed that microbiota-gut-brain interactions are partly managed by the immune system. Accordingly, this study aimed to clarify the correlations between antibiotic-induced microbial dysbiosis, cognitive reactivity to sad mood (CRSM), and concentration of the antibody secretory immunoglobulin A (sIgA). Participants, which finished an antibiotic treatment within the past three months (n = 47), were compared to control participants (n = 60). Participants’ CRSM was measured using the Leiden Index of Depression Sensitivity (LEIDS-R). Antibody levels of salivary sIgA were investigated by obtaining saliva samples from the participants. Results indicated that antibiotic use was not associated with remarkable differences in sIgA concentration or depression sensitivity, i.e. CRSM. However, based on exploratory observations the preliminary idea of antibiotic use resulting in sex-specific responses was developed and is proposed valuable to be investigated in future research. Moreover, it was examined if antibiotic use can be considered a moderator in the relation between sIgA concentration and CRSM. Antibiotic use did not display a moderating role and CRSM was not predicted by sIgA concentration. The findings within this study were limited by a reduced dataset of sIgA concentrations. Ultimately, in contrast to the hypothesized outcome antibiotic-induced microbial dysbiosis was not associated with a decreased sIgA concentration or increased depression sensitivity of healthy individuals within this study. To clarify the correlation between the microbiota-immune-brain axis, antibiotic use, and mental health future research is needed.Show less
