Making your gut happy might help angry arthritis-affected joints, a new study says.

A prebiotic fiber supplement helped ease pain in people with knee arthritis, researchers recently reported in the journal Nutrients.

The results suggest that improving gut health could be a new way to treat arthritis, researchers 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,” lead researcher Afroditi Kouraki said in a news release. She’s a research fellow at the University of Nottingham in the U.K.

The gut microbiome contains trillions of bacteria, and these play a wide-ranging role in people’s health, researchers said.

This study focused on inulin, a natural dietary fiber found in chicory root, Jerusalem artichokes and other vegetables.

For the new clinical trial, researchers recruited 117 people with knee arthritis and assigned them to one of four groups for six weeks.

One group was given inulin supplements; another, inulin plus physical therapy. A third group got physical therapy alone, and the fourth, a placebo treatment.

Both inulin and physical therapy reduced knee pain on their own, results showed.

However, inulin also improved patients’ grip strength and reduced their pain sensitivity, measures linked to how the nervous system processes pain.

The dropout rate for the inulin group was just under 4%, compared to 21% for those in the physical therapy group, researchers said. This suggests that a daily supplement might be easier to keep up with than regular exercise.

Results showed that people taking inulin had higher levels of glucagon-like peptide-1 (GLP-1), a hormone released by the gut that has been linked to pain regulation and muscle health. It’s the same hormone targeted by cutting-edge weight-loss drugs.

"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,” said senior researcher Ana Valdes, a professor of medicine at the University of Nottingham.

“This could have implications not just for osteoarthritis, but for understanding how gut health influences aging and physical resilience more broadly,” Valdes said in a news release.

Inulin also appeared to increase levels of butyrate, a fatty acid produced by the gut that can influence inflammation and pain pathways throughout the body.

Lucy Donaldson, director of research at Arthritis UK, said researchers are starting to explore the role of the gut microbiome in how people experience pain.

“This exciting preliminary research highlights how diet and physiotherapy can act in different ways to have benefits for people with arthritis,” Donaldson, who was not involved in the study, said in a news release. “We know a variety and balance of healthy foods, including fiber, and regular physical activity matter, and we’re glad to be supporting research that explores how they work to help people with arthritis.”