How fasting reduces inflammation

Luise Heine has been an editor at since 2012. The qualified biologist studied in Regensburg and Brisbane (Australia) and gained experience as a journalist in television, in the Ratgeber-Verlag and in a print magazine. In addition to her work at , she also writes for children, for example for the Stuttgarter Kinderzeitung, and has her own breakfast blog, “Kuchen zum Frühstück”.

More posts by Luise Heine All content is checked by medical journalists.

MunichWhen fasting, many people tend to think about losing weight. The renouncement of solid food should also have a soothing effect on diseases such as diabetes mellitus, rheumatoid arthritis or migraines. Researchers have now deciphered why this could be.

The 40-day fasting period begins on Ash Wednesday. For many, this is an occasion to cut back significantly on worldly pleasures. While some primarily want to lose weight, others do without because they are “therapeutic fasting”. It has long been known that the metabolic change during fasting has a positive effect on inflammatory processes. Prof. Vishwa Deep Dixit from the Yale School of Medicine and his team have now investigated this mechanism and how it affects the immune system.

Alternative fuel calms the immune system

They discovered that ketone bodies (ß-hydroxybutyrates), which the body forms from fatty acids during fasting, play a key role. They serve as an alternative source of energy for the organism in times of hunger, strict diet or extreme physical activity.

However, ketone bodies not only function as fuel, they also calm the immune system. They inhibit the so-called inflammasome, a complex of different proteins that sits on the surface of phagocytes. This complex activates the phagocytes and invokes other actors in the immune system - the start of an inflammatory process. This is exactly what the ketone bodies prevent by impairing the ability of the immune cells to communicate.

Relevance to many diseases

At least that is what experiments the researchers carried out on isolated human phagocytes and mice suggest. The latter were bred to be particularly prone to inflammatory diseases. The scientists fed the rodents a diet rich in ketones and were able to prove that this reduced inflammation.

"This mechanism could be relevant in many diseases in which inflammatory processes play a role," says Dixit. By fasting, one could steer the stimulated inflammatory process that rages in the body in diabetes, rheumatism, etc. back into more normal channels. The researchers have not yet been able to make a statement as to how long someone has to fast in order to make use of this effect. “Our next step will be to better understand the molecular mechanisms involved,” Dixit told

Guidance from fasting experts

Fasting means voluntarily giving up solid food and luxury foods for a defined period of time. It is important to drink enough. Most people fast for seven days. There are also two relief days and two build-up days. With medical therapeutic fasting, the fasting cure usually lasts at least two weeks, but it can also be extended to four weeks. Experts recommend fasting under the guidance of professionals, especially if someone has chronic conditions.

Source: Yun-Hee Youm et al. The ketone metabolite β-hydroxybutyrate blocks NLRP3 inflammasome - mediated inflammatory disease. Nature Medicine, 2015; DOI: 10.1038 / nm.3804

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