A new study has found that a prebiotic fibre supplement can reduce pain, enhance grip strength, and lower pain sensitivity in people living with knee osteoarthritis (OA), while also achieving markedly better adherence than a digital physiotherapy programme. The findings come from the INSPIRE clinical trial, led by researchers at the University of Nottingham, and point to a simple, diet-based approach that may complement or, in some cases, outperform existing non-pharmacological interventions.
The trial demonstrated that a daily supplement of inulin—a naturally occurring dietary fibre found in foods such as chicory root and Jerusalem artichokes—significantly reduced pain levels among participants with OA. Published in the journal Nutrients, the results suggest that targeting gut health may offer a promising and accessible strategy for managing a condition that affects hundreds of millions of people globally, particularly older adults.
Knee osteoarthritis remains a leading cause of chronic pain and disability, with current treatment options often centred on pain medications or structured exercise programmes. However, medications can carry risks of side effects, and exercise regimens are frequently difficult for patients to maintain over time. In this context, a dietary supplement that is easy to incorporate into daily routines may provide a practical and sustainable alternative or complement to existing therapies.
According to lead author Dr Afroditi Kouraki, the findings highlight the potential of small dietary changes to deliver meaningful clinical benefits. Adding a fibre supplement to everyday meals, such as breakfast or yoghurt, could reduce pain and improve physical function without requiring substantial lifestyle disruption. This ease of integration may explain the notably low dropout rate observed among participants assigned to the inulin group.
The underlying mechanism appears to involve the gut microbiome, the complex community of microorganisms in the digestive system that plays a crucial role in overall health, including pain perception. Inulin acts as a prebiotic, nourishing beneficial gut bacteria and promoting the production of short-chain fatty acids such as butyrate. These compounds are known to influence inflammation and pain signalling pathways. Participants who took inulin also showed increased levels of glucagon-like peptide-1 (GLP-1), a hormone associated with both pain regulation and muscle function, with higher levels linked to improved grip strength.
The six-week randomised controlled trial included 117 adults with knee OA and compared four groups: inulin alone, physiotherapy-supported exercise alone, a combination of both, and a placebo. While both inulin and physiotherapy reduced knee pain, only inulin improved grip strength and pain sensitivity—key indicators of how the nervous system processes pain. Importantly, adherence differed substantially, with just 3.6% of participants in the inulin group dropping out compared to 21% in the physiotherapy group. These findings underscore the potential of gut-targeted interventions as a safe, well-tolerated, and scalable approach to improving quality of life for people with osteoarthritis, while also opening new avenues for research into the broader gut–muscle–pain connection.
More information: Afroditi Kouraki et al, Effect of Prebiotic Supplementation With and Without Physiotherapy on Pain and Pain Sensitivity in People with Knee Osteoarthritis, Nutrients. DOI: 10.3390/nu18050714
Journal information: Nutrients Provided by University of Nottingham
