A new study suggests that people with a certain blood type are more severely affected by Covid-19. Is this really true? What other connections there are between health and blood types? Two experts give answers.
Can the blood group have an influence on the course of viral diseases??
A new study has investigated whether people with a certain blood group suffer more from corona than others. "We see a 50 percent higher risk of severe Covid 19 in people with blood group A," says Professor Dr. Andre Franke from the Institute of Clinical Molecular Biology at Christian Albrechts University in Kiel, Germany.
The molecular biologist, together with his colleagues at Oslo University Hospital, investigated the connection between the course of a covid 19 disease and the blood group of the affected person. Result: Study participants with blood group A suffered particularly frequently from respiratory problems.
Depending on their blood group, people are more susceptible to certain diseases
According to the German Red Cross, 43 percent of Germans have blood group A. Do they need to be particularly concerned now? No! Other chromosomes, cell components that carry the genetic material, also influence the course of a disease. "In addition, there are also non-genetic risk factors that need to be considered," says Professor Franke. Although genetics plays a role, it is not solely responsible for disease and its progression.
The fact that diseases are related to our blood group has been studied many times before. "People with blood types A, B and AB are more likely to have heart disease and thrombosis, unlike people with blood type 0, because the blood clumps together faster," says Franke. According to studies, people with blood group A are also more affected by diarrheal diseases.
This is related to multisugars that people with blood type A carry on the surface of many cells. Polysaccharides are carbohydrates that are indispensable for metabolism and serve as energy carriers. Germs that lead to gastrointestinal problems are particularly likely to adhere to these sugars.
"People with blood type A, B and AB have a higher probability of developing thrombosis."
Prof. Dr. Andre Franke
biologist and researcher at the Institute for Clinical Molecular Biology at Kiel Christian Albrechts University
Scientists see a link with blood traits in another infectious disease. "There is a clear link between blood type and malaria," says dr. Christof Weinstock, vice chairman of the Immunohematology and Immunogenetics Section of the German Society for Transfusion Medicine and Immunohematology.
For example, people with blood group 0 are less susceptible to malaria than people with other blood groups. Malaria parasites particularly like to attach to a special protein on the blood cell surface, a receptor. In this way, the parasite can easily gain access to the cells and multiply there. However, many people who themselves or their relatives come from African areas lack this one blood group characteristic, which favors malaria infection. Say: They are often genetically protected.
Why pregnant women need to be examined in particular
Next to the AB0 system, the rhesus system is the second most important classification for blood groups. About 80 percent of rhesus-negative people form antibodies against the rhesus-positive factor when they come into contact with it. This can be problematic during pregnancy if the woman is rhesus negative. If the baby is rhesus-positive and blood is exchanged between mother and child – during birth, for example – the woman forms antibodies.
This is not a problem with the first child – but it is with a subsequent pregnancy. Because the mother's antibodies, which are already present in large quantities before birth, can cross the placental barrier and destroy the red blood cells of the fetus. "That's why rhesus prophylaxis was introduced. If an expectant mother is rhesus-negative, she will have 28 weeks of pregnancy. We inject the antibody during the week," explains Dr. Christof. Weinstock. This has a similar effect to desensitization: the mother's immune system continues to "sleep" and does not form antibodies.
What is the blood group diet all about??
Let's ame that it would be easy to lose weight and feel good in your skin if you knew your blood type – that would be a dream come true. And in the theory of American naturopath Peter D'Adamo, this means the following: People with blood group 0 should avoid all dairy products, people with blood group A should best eat a vegan diet.
Blood group B tolerates dairy products and eggs best, and those with blood group AB are supposedly really lucky – they tolerate everything! But the diet earns a lot of criticism. "There is no scientific evidence that D'Adamo's theses are correct," says Dr. Weinstock. As much as we can read in our blood – which diet we tolerate is probably not one of them unfortunately.