Tuesday, 3 July 2018

A high-fiber diet protects mice against the flu virus


Dietary fiber increases survival in influenza-infected mice by setting the immune system at a healthy level of responsiveness, according to a preclinical study published May 15 in the journal Immunity. A high-fiber diet blunts harmful, excessive immune responses in the lungs while boosting antiviral immunity by activating T cells. These dual benefits were mediated by changes in the composition of gut bacteria.

From a public health perspective, influenza A infection is especially relevant because it is one of the most common viral diseases worldwide. Up to 20% of people are infected each year, resulting in substantial morbidity and mortality. In the new study, Marsland and his team found that mice were protected from influenza infection by a diet supplemented with either the highly fermentable fiber inulin or SCFAs.

Specifically, these treatments led to both the dampening of the innate immune response that is typically associated with tissue damage, and also the enhancement of the adaptive immune response that is charged with eliminating pathogens.

Taken together with past studies, the new findings suggest that the modern Western diet consisting of food high in sugar and fat and low in fiber could increase susceptibility to inflammatory diseases while decreasing protection against infections. From a therapeutic standpoint, additional research is needed to determine how much fiber, and what type of fiber, would be most effective in humans.

For their own part, Marsland and his team will further examine how dietary changes influence the immune system, and particularly how changes in the gut can influence lung diseases. Currently, they are planning dietary intervention studies in humans to determine how their results could best be translated to day-to-day living.

See:

AurĂ©lien Trompette, Eva S. Gollwitzer, CĂ©line Pattaroni, Isabel C. Lopez-Mejia, Erika Riva, Julie Pernot, Niki Ubags, Lluis Fajas, Laurent P. Nicod, Benjamin J. Marsland. Dietary Fiber Confers Protection against Flu by Shaping Ly6c − Patrolling Monocyte Hematopoiesis and CD8 T Cell MetabolismImmunity, 2018; 48 (5): 992 DOI: 10.1016/j.immuni.2018.04.022

Posted by Dr. Tim Sandle

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