Why has Covid-19 affected some people much more severely than others? There are several possible answers to this question. Christoph Wilhelm and Christian Bode of the University of Bonn believe they have found one.
Christian Bode is a doctor in the intensive care unit at the University Hospital in Bonn and already at the beginning of the pandemic he started treating patients whose illness from Covid-19 is extremely severe. However, he did not observe the cytokine storm that is often cited as the cause of the severe forms of the disease – an overreaction of the immune system that leads to a lot of inflammation in the body. There must be another explanation for the severe, often fatal course of the disease.
So Bode began working with immunologist Christoph Wilhelm on a study that compared changes in the metabolism of patients with Covid and those with the flu. As they worked, the two scientists discovered a difference that appeared to have a huge impact on the immune system’s ability to fight disease.
Ketone bodies as an energy source
Anyone who has been really sick knows this symptom – no appetite. At first this is not a problem because the human body has a plan. If we eat nothing or eat very little and thus lack sufficient carbohydrates as a source of energy for the body, the metabolism adjusts. „The inflammatory reaction always consumes a lot of energy, which has to come from somewhere,“ explains Christoph Wilhelm. That’s why when you’re hungry, your body starts burning fat. In this way, the so-called ketone bodies, which are so rich in energy that they replace the missing carbohydrates. One of these ketone bodies is beta-hydroxybutyrate (BHB).
Scientists have found that flu patients build up large amounts of ketone bodies. However, no such thing is observed in patients with Covid-19. In the course of their research, the scientists found that the missing ketone bodies apparently have a direct effect on the state of the immune system – and thus determine how severe the illness will be.
Both killer T cells and helper T cells, two major components of the immune system, show signs of exhaustion in Covid-19 sufferers – apparently because they lack ketone bodies as an energy source.
Diet can be key
Wilhelm and Bode still cannot answer the question of why the level of ketones does not rise enough in Covid-19 patients and thus the immune system is paralyzed. However, they have several hypotheses: it may be related to the nutritional status of those affected before infection.
Dietician Hans Hauner, director of the Department of Nutritional Medicine at the Technical University of Munich, knows how great the influence of nutrition is on the immune system and, accordingly, on the course of diseases. „Diet plays a big role in disease and infection,“ he says. „We know from large studies, especially from England, that people who are overweight or obese always do worse with Covid-19. Both complication rates and mortality were significantly higher.”
How beneficial is the ketogenic diet?
The nutritionist finds the work of his Bonn colleagues very exciting, as it brings to the fore a chronically neglected part of medicine: what we eat and what we don’t eat can have very specific consequences for our health. However, food can not only make us sick, but also protect us, even heal us.
Christoph Wilhelm and Christian Bode do tests on mice. Weak and exhausted immune cells are restored when they are supplied with sufficient ketone bodies. For example, by purposefully changing a diet that is very high in fat and low in carbohydrates. Also known as the keto diet. Animals fed this way recovered from SARS-CoV-2 and their mortality was significantly reduced compared to the control group.
What does a healthy diet include?
However, all three experts advise against experimenting with a ketogenic diet on your own. It is not necessary. „A healthy plant-based diet with little meat is also the best defense against infectious diseases,“ says nutritionist Hauner. Vegetables contain many micronutrients that the immune system needs to function as fully as possible.
Omega-3 fatty acids, which are found in fish, but also in canola and other vegetable oils, have an anti-inflammatory effect. On the other hand, the fatty acids in meat promote inflammation.
Of course, even the best diet can’t prevent infection, Hauner points out. The question of whether the human body can be treated with the help of ketone bodies in the case of an acute infection with Covid-19 as well as the mice of the Bonn scientists, needs to be further investigated.
Intensive care physician Bode and immunologist Wilhelm are already working on further studies.