Inulin cuts knee arthritis pain in six-week trial

University of Nottingham researchers reported on Oct. 27 that daily inulin reduced knee osteoarthritis pain in a six-week randomized trial of 117 adults, according to a ScienceDaily summary of a Nutrients paper.

The trial matters because it tested a low-burden add-on approach for a common chronic pain condition, with 3.6% dropout in the inulin-only group versus 21% in the physical-therapy-only group.

Participants were assigned to one of four groups: daily inulin, digitally supported physical therapy exercises, both interventions together, or placebo. The design let researchers compare the fiber supplement with exercise support and examine whether combining the two added benefit.

Inulin is a prebiotic fiber, meaning it feeds selected gut bacteria rather than adding live bacteria as probiotics do. The ScienceDaily material said it occurs naturally in foods including chicory root and Jerusalem artichokes.

Afroditi Kouraki, lead author from the University of Nottingham School of Medicine, said: "This study raises the exciting possibility that a simple dietary change -- adding a fiber supplement to your breakfast or yogurt -- could meaningfully reduce pain and improve physical function."

The reported benefits were not limited to knee pain. Participants taking inulin also showed improved grip strength and reduced pain sensitivity, a measure of how strongly the nervous system responds to potentially painful stimulation.

The researchers reported higher levels of butyrate, a short-chain fatty acid produced when gut bacteria ferment fiber. They also observed higher glucagon-like peptide-1, or GLP-1, a gut hormone involved in blood sugar and appetite regulation that has also been linked in research to pain regulation and muscle health.

The inulin tested in the trial was not a GLP-1 drug. The study examined whether changing the gut microbiome could influence the body’s own GLP-1 production.

Kouraki said: "Our findings suggest that targeting gut health with a prebiotic supplement is a safe, well-tolerated, and effective way to reduce pain in people with knee osteoarthritis. The very low dropout rate compared to the exercise group is also encouraging from a public health perspective -- people were able to fit this supplement easily into their daily lives."

The findings apply to adults with knee osteoarthritis in this six-week trial. They do not establish whether inulin would help people with other forms of arthritis, people without osteoarthritis, or patients followed for longer periods.

The study cannot show that GLP-1 caused the grip-strength improvement. The reported link between higher GLP-1 levels and better grip strength was an association, and the source summary did not provide absolute pain-score changes, confidence intervals, dose, funding details, conflict disclosures or adverse-event rates.

The results also do not show that fiber supplements should replace exercise, physical therapy, pain medicines or other established osteoarthritis care. The evidence supports further testing of inulin as a possible complementary approach, particularly because the trial was small and lasted only six weeks.

Senior author Ana Valdes from the University of Nottingham School of Medicine said: "The link we observed between GLP-1 and grip strength is particularly intriguing and points to a broader gut-muscle-pain axis that warrants further investigation. This could have implications not just for osteoarthritis, but for understanding how gut health influences aging and physical resilience more broadly."

Source: ScienceDaily Health summary of University of Nottingham research published in Nutrients, Oct. 28, 2026.

Atlas360 reports health research and does not provide medical advice.