A new study has revealed that eating a diet rich in fiber can protect against allergic asthma by triggering changes in the immune system.

Benjamin Marsland from the University Hospital of Lausanne in Switzerland and colleagues found that levels of dietary fiber, found in fruit and vegetables, can influence the balance of microbes in the gut in ways that make the airways more or less prone to the inflammation seen in allergic airway diseases, New Scientist reported.

The researchers, who looked at how the immune and inflammatory responses of mice varied with the fiber in their diet, found that when the mice were exposed to an extract of house dust mites, those fed with less fiber had double the number of a specific type of immune cell associated with asthmatic inflammation in their airways, than those on a standard diet.

It was found that mice given additional fiber supplements on top of a standard diet showed a reduction in these immune cells, but only if the supplement was easily fermentable in the gut.

The study was published in Journal Nature Medicine.