Chronic pain, pain that persists or returns for more than three months, can affect people’s emotional well-being and is often accompanied by difficulty concentrating or remembering things. While they can be effective for some patients, available treatments for chronic pain do not always relieve all the other symptoms associated with it.
Some medical researchers have been exploring the potential of dietary interventions to relieve chronic pain and other connected symptoms. One of these is intermittent fasting, which entails alternating set periods of eating with periods during which people drink only water or unsweetened tea and coffee.
Researchers at Zhengzhou University and its First Affiliated Hospital recently conducted a study investigating the effects of intermittent fasting on chronic pain in mice. Their findings, published in Brain, Behavior, and Immunity, suggest that fasting for set hours can alter gut bacteria and influence the connection between the digestive tract and the brain, which may in turn reduce pain sensitivity and improve mental function.
“This study grew from our longstanding interest in how the gut–brain axis contributes to chronic pain and its associated cognitive and affective disturbances,” Kenji Hashimoto, co-author of the paper, told Medical Xpress.
“We were particularly interested in intermittent fasting as a promising nonpharmacological intervention and hypothesized that its beneficial effects might be mediated by alterations in the gut microbiota and microbiota-derived metabolites. Our main objective was to clarify these underlying mechanisms, which ultimately led us to identify an intermittent fasting–Alistipes finegoldii–hippuric acid–STING neuroimmune axis associated with improvements in pain, cognition and anxiety-like behavior.”
How fasting affects pain and brain function in mice
Research evidence has increasingly highlighted the potential benefits of intermittent fasting, suggesting that it can promote weight loss and improve insulin sensitivity, blood glucose regulation, blood pressure and cholesterol levels, particularly in people who are overweight. Whether it can influence people’s pain sensitivity, mental function and emotional well-being, however, remains unclear.
Hashimoto and his colleagues studied several mouse models of chronic pain: mice that experience chronic pain due to specific injuries, inflammation or other experimentally controlled conditions. For 38 days, some of the mice alternated 24 hours of fasting with 24 hours of unrestricted feeding, while others always had unlimited access to food.
“We assessed pain sensitivity, memory and anxiety-like behavior, together with intestinal barrier integrity, neuroinflammation, gut microbiota composition and circulating metabolites,” Hashimoto explained.
“Using microbiome and metabolomic analyses, followed by supplementation with Alistipes finegoldii or hippuric acid and pharmacological manipulation of STING signaling, we tested whether this microbiota–metabolite–neuroimmune pathway mediates the beneficial effects of intermittent fasting.”
The researchers observed that mice with chronic pain who followed the intermittent fasting regimen appeared to exhibit reduced sensitivity to normally harmless touch and heat. In addition, fasting appeared to improve their performance on simple tasks and reduce anxiety-like behaviors.
Collected data suggested that fasting had strengthened the mice’s intestinal barrier, reduced neuroinflammation and altered the composition of their gut microbiota. A species of gut bacteria that appeared to consistently increase with intermittent fasting was Alistipes finegoldii.
“We identified a previously unrecognized intermittent fasting–Alistipes finegoldii–hippuric acid–STING neuroimmune pathway linking dietary intervention to improvements in pain, cognition and anxiety-like behavior,” Hashimoto said.
“Our findings suggest that the beneficial effects of intermittent fasting are mediated not only by general metabolic changes but also by specific alterations in the gut microbiota and microbiota-derived metabolites that modulate neuroinflammation.”
Guiding future research into the gut–brain connection
This study suggests that intermittent fasting can change the composition of the gut microbiota, particularly in mouse models of chronic pain. Interestingly, the team also found that supplementing mice with Alistipes finegoldii, the bacterial species that increased with fasting, reproduced the pain-relieving effects and cognitive improvements observed in fasting mice.
“These results may open new avenues for nonpharmacological interventions, microbiota-based therapies, metabolite supplementation and STING-targeted strategies for chronic pain and its associated neuropsychiatric comorbidities,” Hashimoto said.
The authors’ findings could soon inspire other researchers to conduct animal studies exploring the potential benefits of Alistipes finegoldii supplements or to determine whether intermittent fasting similarly reduces pain sensitivity in humans. In their next studies, Hashimoto and his colleagues will try to further define the cellular and molecular mechanisms underlying the Alistipes finegoldii–hippuric acid–STING pathway they uncovered.
“We wish to identify the specific cell types in which STING signaling is modulated,” Hashimoto added. “We also plan to investigate potential sex differences and determine whether additional microbial species and metabolites contribute to the beneficial effects of intermittent fasting, while validating these findings in larger longitudinal clinical studies. Ultimately, we hope to determine whether microbiota- or metabolite-based interventions can be translated into safe and effective therapeutic strategies for chronic pain and its associated cognitive and affective comorbidities.” https://medicalxpress.com/news/2026-08-intermittent-fasting-reveals-gut-brain.html
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