In the three-month study, the healthy participants increased their daily dietary fibre intake by 10 grams, which is equivalent to about four apples or 3 deciliters of oatmeal. To study the significance of the increased fibre intake, gut bacteria were collected at the beginning and the end of the study. These gut bacteria were then transplanted into mice which were fed a low-fiber Western diet. In the group of animals transplanted with intestinal bacteria from the beginning of the study, the researchers observed damage of the mucus layer. The opposite was seen in the group with increased consumption of dietary fibres, where the mucus layer looked fine.

"The result highlights the significant role that dietary fibre has for our intestinal bacteria, which in turn contributes to maintaining the important mucus barrier," says Rachel Feeney, Doctoral student at the Department of Molecular Biology at Umeå University.