The study, conducted by researchers at Henan University, found that probiotic supplementation significantly improved cognitive function in patients with cognitive impairment.
This finding could strengthen the case for the gut-brain axis as a therapeutic target in neurodegenerative diseases like Alzheimer’s.
This analysis confirms what many in the field have suspected — that manipulating gut microbiota through probiotics has real potential to support brain health.
The results suggested that specific probiotic strains, administered over short intervention periods, could yield the most pronounced effects on cognition.
Single-strain probiotics and short-term use most effective
The research team analysed data from 10 randomized controlled trials (RCTs) involving 778 participants with cognitive impairment.
Their meta-analysis found a moderate but statistically significant improvement in cognitive function among those taking probiotics compared to placebo.
The greatest cognitive gains were seen in studies using the Mini-Mental State Examination (MMSE) to assess outcomes, showing a standardised mean difference (SMD) of 0.88.
Single-strain probiotics delivered stronger results than multi-strain formulations, with an SMD of 0.81. Interventions lasting 12 weeks or less showed the most substantial improvements (SMD of 0.61).
On the other hand, longer interventions beyond 12 weeks showed diminished returns.
This showed that probiotics had a clear and positive effect when used correctly — short, focused interventions using a single probiotic strain appeared to offer the greatest benefit to patients with cognitive impairment.
The gut-brain axis: From theory to treatment
The gut-brain axis has been a popular research area in recent years, but this study could help solidify its relevance in clinical practice.
The gut-brain axis describes the communication network between the gut microbiota and the brain, affecting mood, cognition, and mental health through a mix of neural, hormonal, and immune pathways.
Probiotics are thought to positively influence this system by reducing inflammation, regulating neurotransmitters like serotonin and dopamine, and improving neural signalling.
Inflammation and oxidative stress — both implicated in neurodegenerative diseases — can be mitigated through a healthier gut microbiome.
This area of research has moved beyond mere theory. The current study’s findings showed that probiotics could translate into meaningful improvements in cognitive function, likely through the aforementioned biological mechanisms.
Challenges remain: Dosage and long-term effects still unclear
While the results were promising, the study also highlighted important gaps.
The optimal dosage and frequency of probiotic supplementation remained uncertain, as the included trials varied widely in the strains used, dosing formats, and intake schedules.
Some studies did not even specify intervention frequencies, limiting the ability to establish standardised recommendations.
Further complicating the picture, longer-term studies did not show the same benefits.
In fact, interventions extending beyond 12 weeks appeared less effective.
This raises questions about the sustainability of probiotic effects and whether cognitive improvements plateau or even decline after initial gains.
The study’s authors suggested that future research focus on determining ideal dosing strategies and longer-term outcomes, noting that “without this data, it is difficult to develop standardised guidelines for clinical use”.
Market potential and regulatory considerations
The global probiotics market is already booming, but these new findings could accelerate demand for cognitive health-focused products.
With dementia projected to affect over 78 million people worldwide by 2030 and 152.8 million people by 2050, the need for accessible, affordable interventions is only growing.
However, companies looking to enter this space must navigate regulatory hurdles.
While organizations like the International Scientific Association for Probiotics and Prebiotics (ISAPP) recommend a minimum daily dose of one billion colony-forming units (CFUs), no official guidelines specify strains or formulations for cognitive health.
This leaves manufacturers responsible for backing their claims with solid clinical data.
Regulators may soon require more rigorous testing and clearer labelling as the category matures.
Suppliers should be prepared to meet these demands by investing in high-quality trials and transparent product formulations.
A call for interdisciplinary collaboration
The study’s authors also called for greater collaboration among neuroscience, microbiology, and clinical medicine to unlock the full potential of probiotics in cognitive health.
As this is a complex issue that requires a multidisciplinary approach, combined efforts are necessary in order to refine probiotic therapies to make them a safe and effective part of managing cognitive decline.
For now, the message to the nutrition and supplementation industry is clear: the gut-brain axis is no longer a theoretical concept — it’s a commercial and clinical reality, and probiotics may play a significant role in the next generation of cognitive health solutions.
The researchers concluded: “The meta-analysis conducted in this study revealed that probiotics can enhance cognitive abilities in patients with cognitive impairment.
“Furthermore, this study furnishes a robust scientific rationale for the potential application of probiotics in areas encompassing neurodegenerative diseases and mental health concerns.
“Future research endeavours should concentrate on refining the dosage and administration protocols of probiotics to ensure the maximization of their salutary effects on brain health.
“Concurrently, we advocate for interdisciplinary synergy, amalgamating the expertise of neuroscience, microbiology, and clinical medicine to propel advancements in probiotics research pertaining to brain health.”
Source: PLOS One
“Efficacy of probiotics in patients with cognitive impairment: A systematic review and meta-analysis”
https://doi.org/10.1371/journal.pone.0321567
Authors: Miaomiao Ma, et al.
