New research shows how fibre affects the immune system
Victor Castro-Alves has used mass spectrometry methods to identify oligomers from dietary fibres.
Örebro researcher Victor Castro-Alves has discovered why fibre is good for the immune system – at the cellular level. His findings may eventually help make it possible to use food as a medicine for inflammatory bowel diseases like IBS and IBD. In the subsequent study, participants will eat blue muffins so that researchers can follow the fibre’s path through the body.
The research results are published in Carbohydrate Polymers (Elsevier): Bioactive arabinoxylan oligomers via colonic fermentation and enzymatic catalysis: Evidence of interaction with toll-like receptors from in vitro, in silico and functional analysis.
Dietary fibre is good for both the stomach and the gut flora. It keeps the stomach stable and becomes food for the good bacteria in the gut flora. Victor Castro-Alves is interested in the third effect – that dietary fibre directly impacts the cells in the gut and the immune system.
He has investigated how fibres from wheat and oats are broken down in the colon to form so-called oligomers and how these affect the immune system’s intestinal cells.
Inhibit or activate
The Örebro researcher studied what happened to the fibres when fermented in a lab environment comparable to the colon. The results show that the oligomers produced by the fibres could either inhibit or activate specific receptors on the cells. Long oligomers with multiple branches were found to have a greater impact than straight oligomers.
This discovery means that the fibres are not only food for gut bacteria but also affect the immune system directly by interacting with cells in the gut.
“It was a time-consuming endeavour because we methodically investigated how each of these unique molecular structures reacted with intestinal cells,” says Victor Castro-Alves, researcher in chemistry at Örebro University.
“Now we have a working method that we can use to test different kinds of relationships. For example, it can be used to understand what happens in patients with inflammatory bowel diseases like IBS and IBD. We may eventually discover how we can use food to reduce symptoms. There is great potential for the oligomers,” says Victor Castro-Alves.
Everyone has different digestive processes
The project also included studies in which participants were asked to provide faecal samples. The researchers found that although fibre affects gut flora in broadly similar ways, there are differences between people.
“This is not surprising because everyone has different gut bacteria and digestive processes,” says Victor Castro-Alves.
The time it takes for food to pass through the gut is crucial and can vary from 10 to 72 hours. In the next step, called the Blue Muffin Study, participants will eat muffins prepared with dietary fibre, which have been dyed blue with food colouring.
Researchers will analyse the blue-stained stool samples and those that follow to find more answers about fibre's impact on the immune system and, ultimately, human health.
The new project has received over SEK 900,000 from the Lantmännen Research Foundation and is part of Rosetta@oru.
Text: Linda Harradine
Photo: Anh Hoang Nguyen
Translation: Jerry Gray