Prebiotic fiber: Inulin eases knee osteoarthritis pain in study
In a six-week University of Nottingham study, the prebiotic fiber eased knee pain about as well as physiotherapy. Researchers also found more beneficial substances produced by gut bacteria.
Symbolic image · Photo: Otto Wilhelm Thomé (Flora von Deutschland, Österreich und der Schweiz, 1885) / Wikimedia Commons, Public domain (cropped and resized)
A prebiotic fiber eased knee osteoarthritis pain in a small study. That is the finding of the randomized INSPIRE trial by the University of Nottingham, published in the journal Nutrients and presented on Oct. 27, 2026. The researchers studied inulin, a plant fiber found in chicory root and Jerusalem artichokes, among others. The trial involved 117 adults with knee osteoarthritis, split into four groups: inulin, digitally supported physiotherapy exercises, both combined, or a placebo.
After six weeks, inulin and physiotherapy each reduced knee pain on their own. But only the inulin group also saw better grip strength and lower pain sensitivity. The fiber raised levels of butyrate, a substance made by gut bacteria, and of the gut hormone GLP-1; higher GLP-1 levels were linked to better grip strength. In the inulin-only group, 3.6% of participants dropped out, compared with 21% in the physiotherapy-only group.
The researchers stress that the study was small and short and that longer trials are needed. The link with GLP-1 is only a statistical association. According to the authors, fiber should not replace exercise or established treatments.
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