A high-fibre diet curbs allergic inflammation in mouse lungs by shifting the composition of microbes in the gut.

Benjamin Marsland at the University of Lausanne in Switzerland and his colleagues raised mice on diets containing different levels of fibre and exposed the animals to extracts of house-dust mite, a cause of asthma. The resulting lung inflammation was less in mice consuming high levels of fermentable fibre than in those on a low-fibre diet, and the animals also harboured a community of intestinal microbes that generated higher levels of short-chain fatty acids when metabolizing fibre. These fatty-acid molecules boosted the generation of immune cells called dendritic cells that were less able to trigger allergic inflammation in the lungs.

The results provide a possible link between the rising incidence of asthma in developed countries and decreasing dietary-fibre intake.

Nature Med. http://dx.doi.org/10.1038/nm.3444 (2014)