A simple daily fiber supplement reduced arthritis pain and improved strength
A new clinical trial suggests that a simple daily fiber supplement could significantly reduce knee osteoarthritis pain, improve muscle strength, and make the body less sensitive to pain. Researchers discovered that the benefits may be linked to changes in gut bacteria and the hormone GLP-1, revealing a promising new approach to arthritis relief.
Key points
- A six-week trial of 117 adults with knee osteoarthritis found that daily inulin reduced pain and improved grip strength and pain sensitivity.
- Only 3.6% of participants taking inulin alone dropped out, compared with 21% in the physical therapy-only group.
- Researchers linked higher GLP-1 levels to better grip strength, suggesting a possible gut-muscle-pain connection.
A daily prebiotic fiber supplement called inulin reduced knee arthritis pain and improved muscle strength in a clinical trial led by researchers at the University of Nottingham. The six-week randomized controlled study, called the INSPIRE trial, involved 117 adults with knee osteoarthritis and was published in the journal Nutrients.
Participants were assigned to one of four groups: inulin alone, a digital physical therapy exercise program alone, a combination of both, or a placebo. Both inulin and physical therapy independently reduced knee pain, but the supplement also produced improvements in grip strength and pain sensitivity that were not seen with physical therapy alone.
How the supplement works
Inulin is a naturally occurring fiber found in foods such as chicory root and Jerusalem artichokes. It passes undigested into the large intestine, where beneficial gut bacteria ferment it and produce short-chain fatty acids, including butyrate.
Participants taking inulin had increased butyrate levels and higher levels of glucagon-like peptide-1 (GLP-1), a gut hormone linked to blood sugar, appetite, pain regulation and muscle health. Higher GLP-1 levels were associated with better grip strength, though the researchers noted this does not establish that GLP-1 caused the improvement.
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
— Dr. Afroditi Kouraki
Dropout rates and next steps
Only 3.6% of the inulin-only group dropped out of the study, compared with 21% of the physical therapy-only group. The researchers said this suggests a daily fiber supplement may be easier to fit into a routine than a structured exercise program.
The trial was relatively small and lasted only six weeks. The authors said larger studies with longer follow-up are needed to confirm whether the benefits persist and which patients are most likely to respond. They also said fiber supplements should not replace exercise or other arthritis treatments.
