Effects of a probiotic fermented dairy product on hippocampal metabolites, structure and function: an 8-week randomised, placebo-controlled trial in healthy women

Wolfgang Marx et al.

ABSTRACT

Background Fermented foods are a promising yet underexplored intervention for influencing brain function and mental health through the gut–brain axis. Objective The objective of this study was to evaluate the impact of a dairy product fermented with probiotic bacteria on aspects of brain structure and function. Design In a triple-blind, randomised, placebo-controlled trial, 40 healthy women aged 18–55 years were randomised to consume either 130 g per day of a fermented probiotic yoghurt or a placebo for 8weeks. The primary outcome was the between-group differential change from baseline to week 8 in left hippocampal metabolites, measured using magnetic resonance spectroscopy. Secondary outcomes included changes in brain structure and function, faecal microbiome composition and functional potential, mental health, gastrointestinal symptoms, memory and blood markers of oxidative stress and inflammation. Results There was a between-group difference in the change in average left hippocampal glutathione concentration (mean difference in change: −0.49; 95%CI −0.95 to −0.04), as well as brain volume in the hippocampus and nucleus accumbens, although these results did not withstand correction for multiple comparisons. There were between-group differences in the change in average functional connectivity between the left hippocampus and left frontal pole. There was also a significant between-group change in gut microbiome beta diversity. There were no differences in other secondary measures. Conclusion This study provides preliminary evidence that a probiotic fermented dairy product can modulate hippocampal-related outcomes.

 

WHAT IS ALREADY KNOWN ON THIS TOPIC ⇒ The gut microbiome influences brain structure and function via immune, metabolic and neural pathways. Probiotic interventions have been shown to modulate brain activity, but evidence from fermented foods remains limited.

WHAT THIS STUDY ADDS ⇒ This study provides some of the first randomised, placebo-controlled trial evidence that a fermented probiotic dairy product might influence hippocampal glutathione levels, functional connectivity and gut microbiome composition in healthy women. These findings suggest a potential link between probiotic-rich fermented foods and neurobiological processes.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY ⇒ These results support further investigation into dietary interventions targeting the microbiota–gut–brain axis for cognitive and mental health benefits. Future research should explore whether probiotic-rich fermented foods can provide therapeutic benefits in clinical populations with neuropsychiatric conditions.

 

Figure 3

A significant time by group interaction was observed between the seed (left hippocampus) and left prefrontal area. Colour map indicates the t value, and numbers on slice view indicate the z axis in the standard space. The scatter plot shows the direction of changes on functional connectivity between these two regions, and error bars indicate the standard errors. Figure includes only non-imputed cases.

 

LEGGI TUTTO https://gut.bmj.com/content/75/3/511#:~:text=https%3A//doi.org/10.1136/gutjnl%2D2025%2D335398