New Study Associates Dietary Fibre to Flu Protection
Metabolites from intestinal microbiota are crucial determinants of both host-microbe mutualism and, consequently, the disease or health of the intestinal tract. But such host-microbe crosstalk that affects inflammation in peripheral cells, like the lung, is poorly understood.
Now, scientists at the University of Lausanne and Monash University, have discovered that dietary fiber protects against chronic inflammatory diseases by dampening immune responses through short-chain fatty acids (SCFAs).
“What is produced in the gut doesn’t just change what’s in the gut,” Professor Benjamin Marsland from the Department of Immunology said. “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.”
“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,” Professor Marsland said.
Instead of switching off the immune system, the diet was found to specifically activate cells called cytotoxic T cells, which kill cells that are infected with the virus. “In essence, by eating the high-fibre diet the immune system of the mice had been primed to fight against infections,
” he said. “We were very excited by that.”Professor Marsland said it was well-established that dietary fibre can reduce immune responses through turning the immune system off but that the influenza findings were different. “This was about turning a discrete part of the immune system on, which is very novel.”
The team believes these findings could potentially boost the efficacy of flu vaccines by supplementing the diet with the right highly fermentable fibres or by adding SCFAs to vaccines.
They further plan on a clinical work to study whether people who eat different amounts of a soluble plant fibre cited in the paper, inulin, are protected against lung disease. The coound, Inulin, which is attracting attention for its link with ‘healthy bacteria’ is readily available, tolerable and safe, Professor Marsland said.
