For people with IBS, a specially designed fiber blend could support a healthier gut without added pain or bloating, a trial alongside a low-FODMAP diet suggests.
Cutting out foods that leave you bloated or in pain can bring welcome relief. For millions of people with irritable bowel syndrome, or IBS, however, a diet that eases discomfort can come with a trade-off. Restricting certain foods can also reduce fiber intake and the beneficial bacteria that help support gut health.
Researchers at Edith Cowan University (ECU) in Australia have tested a specially formulated fiber blend that could help address that dilemma. Called ur gut, the supplement combines high-amylose maize resistant starch with psyllium husk powder. In a small clinical trial, the blend changed the composition of participants’ gut bacteria without worsening their abdominal pain, bloating, diarrhea, or constipation.
Low-FODMAP diets can reduce beneficial bacteria
IBS is common worldwide and affects nearly 11 percent of Australians. Its cause remains unknown, although stress, infection, and medication are potential triggers. Certain foods, poor sleep, psychological stress, hormonal fluctuations, and lifestyle factors can aggravate symptoms.
One common recommendation is a low-FODMAP diet, which limits certain carbohydrates that gut bacteria readily ferment.
“For years we’ve known that a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) can relieve symptoms, but they can also reduce beneficial gut bacteria and negatively impact fiber intake over time,” said lead author Dr. Tina Yan.
“We wanted to find a way to build better gut health while following a low-FODMAP diet.”
Fiber reshaped gut bacteria without worsening IBS
Scientists at ECU’s Nutrition and Health Innovation Research Institute (NHIRI) developed the blend and trialed it in people with IBS who were following a low-FODMAP diet. Adding fiber in this setting requires care because bacteria can produce gas as they break it down.
“Traditionally, fermentable fibers can be difficult for people with IBS because they can increase gas production and discomfort,” Dr. Yan said.
“What’s exciting about this study is that participants maintained stable symptoms while showing meaningful improvements in their gut microbiota as well as in their gut-related anxiety.”
The changes in participants’ gut bacterial composition were significant, and their extent stood out to ur gut® co-creator Professor Amanda Devine.
“Changes of this magnitude are rarely seen with such a short intervention,” she said.
“The study demonstrated that our targeted dietary fiber blend positively reshaped the gut microbiome in people with IBS following a low-FODMAP diet, supporting beneficial bacteria linked to gut and mental health. This was great to see.”
How two fibers may support gut health
The researchers suspect the explanation lies in how the blend’s two ingredients, resistant starch and psyllium husk, work together. Resistant starch escapes digestion in the small intestine, leaving it available for bacteria to ferment in the colon. Psyllium appears to slow that fermentation, allowing the starch to travel farther into the colon before bacteria break it down. The researchers believe this enhances the production of beneficial metabolites, substances the bacteria produce as they process the starch.
“For many people with IBS, success has traditionally meant simply avoiding certain foods,” said ur gut® co-creator Associate Professor Claus Christophersen.
“Our findings suggest we may also be able to actively rebuild gut health and the microbiome while not making IBS symptoms worse. That’s an important step forward.”
Reference: “Dietary fiber blend improves gut health in patients with irritable bowel syndrome following a low FODMAP diet: a randomized, double-blind control trial” by Ran Yan, Amanda Devine, Johnny Lo, Evania Marlow, Ian C. Dunican, Kanita Kunaratnam, Lesley Andrew and Claus T. Christophersen, 24 September 2026, European Journal of Nutrition.
DOI: 10.1007/s00394-026-04113-5
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