What are blood groups?
The blood-type diet is predicated on our blood groups. A, B, AB and O is the well-known classification of blood on the basis of different antibodies and also based on antigenic substances on red blood cells. These antigens may be glycolipids, glycoproteins, carbohydrates, or proteins. The most important classification is the ABO blood group system and the RhD antigen.
Due to the various structures of red blood cells, blood from different blood types may agglutinate when mixed. Worldwide you can find ca. 45% type O blood, 40% A, 11% B, and 4% AB. 88% are rhesus positive, 12% rhesus negative. People with O- are considered to be universal donors and people with AB+ are universal recipients.
Agglutination is used to identify your blood type. If your blood only agglutinates with antibodies you can find in blood group B, you may have blood group A.
What is the Blood-Type Diet?
The Blood-Type Diet advises people to eat according to their ABO blood group. By doing so, PJ. D’Adamo proposed in his book „Eat Right 4 Your Type“ published in 1996 you can improve your health and decrease the risk of chronic diseases such as cardiovascular disease. The key to your success is eating according to your blood group.
More than 7 million copies have been sold in over 60 languages.
Thus, D’Adamo postulates in his Blood-Type Diet theory that people with blood group O should eat just like our ancestors of the hunter-gatherer era. Animal protein is ranked first while grain products should be avoided.
Group A is considered to have evolved when our ancestors settled down into agrarian societies. Therefore, group A should go best with a vegetarian diet and prefer grains, fruits, and vegetables. Similarly, group B is said to have evolved from nomadic tribes and should thrive on dairy products. Accordingly, people with an AB blood group are supposed to thrive on a combination of vegetables and dairy products. Only eggs and fish are a recommendable source of meat.
Besides, if you are not eating according to your blood type, D’Adamo blames sugar-binding proteins called lectins to cause agglutination and serious diseases.
Is there any truth behind the Blood-Type Diet?
Several studies focused on the statements of D’Adamo and the results are quite striking and definite: The findings do not support the Blood-Type Diet hypothesis. The only blood group which is expected to have beneficial effects on cardiometabolic risk factors, is group A due to its focus on plant-based products. Type-O diet is quite similar to low-carb diets and shows lower serum trigylcerides because of avoiding grains and as a consequence many processed foods such as sugars which appear to affect the blood sugar levels negatively. But it is neglected that this causes serious problems associated with a high consumption of cholesterol.
Plus, there is some evidence that blood group A is rather the ancestral human blood group than group O as D’Adamo said. D’Adamo’s evolution of blood types is fundamentally wrong.
Is there any evidence based on blood groups?
There are thousands of studies based on blood groups and the likelihood to suffer from diseases such as cancer, malaria, and cholera. Non-O blood groups seem to have a higher risk to suffer from thrombosis and vascular diseases compared to group O. Thus, individuals belonging to group B have a lower risk of type 2 diabetes compared to individuals belonging to group O.
To sum it up, the plant-based diet of blood group A is beneficial for everybody no matter what blood group you belong to. Plus, it is never wrong to try to get to the bottom of your own eating habits. Scrutinising your own diet shows you your own room for improvement. That’s why most diets have the potential to work: You occupy yourself with your own nutrition and see what you can improve easily.
However, there is no evidence validating the promised health benefits of D’Adamo’s Blood-Type Diet.
Do you even know what blood group you belong to? If you want to figure it out, go to a blood donation. That’s where I was told to have B+ which is useful for people with B+ and AB+. Have you ever participated in blood donations or did you ever had to get one? Tell us 🙂
Here you can find all sources used for this blogpost.
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