Daily Fiber Supplement Reduced Knee Arthritis Pain and Improved Muscle Strength, Study Finds - Video

Could the secret to easing knee pain be hiding in your breakfast bowl instead of your medicine cabinet?

A simple daily prebiotic fiber supplement may help reduce knee osteoarthritis (OA) pain while improving physical function, according to a new clinical trial published in Nutrients. Researchers from the University of Nottingham found that inulin, a natural fiber found in chicory root, artichokes, and other vegetables, significantly eased pain and improved several health measures in adults with knee OA.

The six-week INSPIRE randomized controlled trial included 117 adults with knee osteoarthritis. Participants were assigned to one of four groups: inulin alone, digital physiotherapy-supported exercise, both treatments combined, or a placebo.

Results showed that both inulin and physiotherapy independently reduced knee pain. However, only participants taking inulin experienced stronger grip strength and reduced pain sensitivity, suggesting improvements in how the nervous system processes pain.

Researchers believe the benefits may begin in the gut. Inulin acts as a prebiotic, feeding beneficial gut bacteria that produce short-chain fatty acids, including butyrate, which may help regulate inflammation and pain. Participants taking inulin also had higher levels of glucagon-like peptide-1 (GLP-1), a gut hormone linked to pain regulation and muscle function. Higher GLP-1 levels were associated with better grip strength, hinting at a possible gut-muscle-pain connection.

The supplement also proved easier to stick with than exercise alone. Only 3.6% of participants in the inulin group dropped out of the study, compared with 21% in the physiotherapy group.

Researchers say these findings suggest that supporting gut health with a prebiotic supplement could become a safe and practical addition to osteoarthritis care. However, they emphasize that the trial was relatively small and lasted only six weeks. Larger, longer-term studies are needed to confirm the benefits and determine whether combining dietary fiber with exercise can provide even greater relief for people living with knee osteoarthritis.

REFERENCE: Afroditi Kouraki, Susan Franks, et al.; Effect of Prebiotic Supplementation With and Without Physiotherapy on Pain and Pain Sensitivity in People with Knee Osteoarthritis. Nutrients, 2026; 18 (5): 714 DOI: 10.3390/nu18050714