There are numerous studies involving intestinal microbes like probiotics and its link with healthy intestines. But these host-microbe in other organs like the lungs were poorly understood, which led to inflammation.

Recently, scientists from the University of Lausanne and Monash University, discovered that dietary fiber protects against inflammatory diseases like flu by reducing the immune response through short-chain fatty acids (SCFAs).

Professor Benjamin Marsland from the Department of Immunology said, “What is produced in the gut doesn’t just change what’s in the gut; it goes into the circulation and changes the immune system at one of the most fundamental levels – the bone marrow – where a lot of our immune cells develop.”  He further added, “We found that the high-fibre diet in mice actually protected against influenza, which was quite a surprise to us because the expectation from our earlier work, and that of others, would be that the immune response would be dampened.”

Consumption of a high fiber diet doesn’t simply switch off the immune system. It specifically activates cytotoxic T cells, which specifically destroy virus infected cells. Professor Marsland said, “This was about turning a discrete part of the immune system on, which is very novel.”

The efficacy of flu vaccines could be boosted by supplementing the diet with enriched fibres or by adding SCFAs to vaccines.