The diet stops the immune system from over-reacting to allergens which causes severe inflammation of the respiratory tract, say researchers at the University of Bonn.
The ketogenic diet is already used to treat epilepsy and some cancers—and the researchers believe it could also help asthmatics.
The biological processes that cause an asthmatic attack were only fully understood a few years ago with the discovery of cells in the immune system called Innate Lymphoid Cells, or ILCs. They help protect the lungs by regenerating damaged mucous membranes, but the reaction is much stronger in the asthmatic, and this causes breathing problems that can even be life threatening.
The Bonn researchers think the ketogenic diet slows the ILC response by changing the way the cells get their energy. The high-fat diet slows the speed at which they grow, and the lack of glucose—derived from carbohydrates—also affects their development.
Normally, an allergen will cause the number of ILCs in the bronchi to increase fourfold, and it can be many times that in an asthmatic. Dr Christoph Wilhelm, one of the researchers, thinks the rise in cases of asthma may be the result of a diet of processed foods, which are high in sugars.