Project Title:
The role of the Gut Microbiome in Cognition and Dementia Risk
Project Partners:
- Dr Harry Jarrett, Heights (PI)
- Dr Ryan McNally, King’s College London
- Sophie Medlin, Heights
- Dr Thomas E Brownlee, University of Birmingham
- Dr Catherin Hughes, NICHE – Ulster University
- Dr Filippos Papadopoulos, Health Economist
Intended Project Outcomes:
The project aimed to consolidate and synthesise the existing scientific evidence from human intervention trials on the role of gut microbiome modulation in supporting cognitive function and cognitive ageing. The report further aimed to incorporate the findings from the evidence synthesis into an economic model to estimate potential cost savings of a probiotic programme implemented across the population. From the evidence produced, through collaboration between academics, industry, healthcare and a health economist, the project sought to produce an accessible impact report for policymakers, healthcare professionals and industry partners.
Secondary objectives included examining whether the effectiveness of interventions varied across key subgroups, including age, sex, and baseline cognitive health status.
Project Objectives:
A comprehensive systematic review and meta-analysis of 33 randomised controlled trials was completed, providing robust evidence that gut microbiome-modulating interventions are associated with small but statistically significant improvements in cognitive outcomes. Multiple subgroup analyses reported stronger effects with certain interventions. Specifically, the evidence-base was strongest for probiotics, whilst interventions of longer duration were associated with greater improvements in cognitive function. Moreover, subgroup analysis based on cognitive health status indicated stronger evidence of an effect in those individuals with compromised cognition at baseline.
The results of the meta-analysis informed the economic modelling approach. Since stronger effects were observed in individuals with compromised cognitive function, the analysis was restricted to individuals with baseline cognitive impairment. This approach aimed to generate the most robust and policy-relevant assessment of the population-level utility of gut microbiome modulation for supporting cognitive health.
A conservative economic model was developed, demonstrating that probiotic supplementation could deliver meaningful quality-of-life gains at a cost well below commonly accepted NHS willingness-to-pay thresholds. The base-case analysis estimated an incremental cost-effectiveness ratio of approximately £4,700 per quality-adjusted life year (QALY) gained, with results remaining robust across extensive sensitivity analyses. Crucially, the findings provide a credible evidence base to support consideration of probiotic supplementation at a population level.
The final output is presented in a clear, accessible format designed to support engagement beyond academia, including policymakers, commissioners and industry stakeholders. The report provides practical recommendations for pilot implementation within existing NHS and public-health pathways, directly addressing the original aim of translating research evidence into real-world impact.
The project strengthened interdisciplinary collaboration across academia, healthcare, industry and health economics, establishing a strong foundation for future partnerships. Feedback from collaborators indicated high interest in future joint projects, particularly those focused on translational research, real-world evaluation and functional food innovation.
Professional Development:
The project provided substantial insight into translating complex scientific evidence into policy-relevant economic outcomes. Working closely with a health economist enabled the development of a conservative yet decision-focused cost-effectiveness model grounded in real-world NHS thresholds and assumptions. This experience provided valuable insights into how economic modelling is conducted and can be used as a tool to provide evidence of cost-effectiveness to policymakers. This further strengthened skills in framing research findings around quality-adjusted life years, value-for-money arguments and budget impact considerations rather than solely clinical outcomes. The experience also enhanced understanding of how uncertainty, sensitivity analyses and transparent assumptions are critical for credibility when informing policy and commissioning decisions. These skills will
directly inform future impact-focused research and engagement with policymakers and industry partners.
Project Achievements/Outputs:
Impact_Graphical_Report<< Download a copy of the Impact Report:
The role of the Gut Microbiome in Cognition and Dementia Risk.
Plans focus on disseminating the outcomes of this project through multiple academic, industry and policy-facing channels. The findings will be presented at academic conferences, including the Nutrition Society Congress 2026, to engage academic and clinical audiences. In parallel, the results of the systematic review and meta-analysis will be prepared for submission to a peer-reviewed journal to ensure wider scientific dissemination of evidence relating to gut microbiome-modulating interventions and cognitive function.
To further support knowledge exchange and recognition of this academic-industry collaboration, the project will be submitted to the NutraIngredients “Nutrition Research Project” award. In addition, the consortium intends to engage with policymakers, commissioners and relevant stakeholders to communicate the key findings of the report and stimulate discussion around the potential role of probiotics as a scalable, low-risk intervention to support healthy cognitive ageing and inform future public-health and dementia care strategies.
MAY 2025