What is the blood group diet

Blood type diet
Food according to blood type

Dr. Michael Klaper

"Your blood type determines your diet and lifestyle." This is the message that the American naturopath Dr. med. D´Adamo worldwide. His books have become bestsellers, although there are barely tenable claims behind his adventurous theories about the blood type diet.

In the United States, the blood type diet received a lot of public attention in 1996. In German-speaking countries, the book with the title "4 Blood Groups" came onto the market one year later. The basic statement of the author Peter J. D'Adamo: Everyone should base their food on their blood group. He describes blood group 0 as the dominant hunter-cave dweller type who needs meat. Blood group A people are gentle vegetarians, and members of blood group B are omnivores that eat dairy products. For many people, this theory provides the justification for including plenty of meat and other animal products in their diet. But the blood type diet has many inconsistencies.

The specter of the blood group diet: lectins made from beans

One of the characteristics of the book is the terrifying phantasms that the author conjures up in the case of improper nutrition without providing any scientific evidence. For example, D´Adamo bases his theory largely on the effects of lectins. These are proteins found in certain foods like legumes and wheat. They can cause the red blood cells to stick together. The American naturopath blames lectins for serious disorders in the whole body, from the adhesion of blood cells to organ damage and kidney failure. He even scares his readers with the story of ex-KGB agent Georgie Markov, who was murdered with an injection of the ultra-powerful lectin ricin. D'Adamo also claims that "certain beans and legumes, especially lentils and kidney beans, contain lectins that are deposited in muscle tissue, making them increasingly alkaline and less efficient". A serious scientific attack and an alarming thought for everyone with blood group 0. "After you have eaten a bowl of chilli beans or lentil stew, lectins are deposited in your muscles, impair their function, change their acidity and reduce your physical performance," writes D'Adamo.

Blood group O type: The hunter

This person has the oldest blood group in evolutionary terms. 0 types are meat eaters, have a robust digestive tract and are equipped with a resilient immune system. In addition to meat, many vegetables and fruits are also well tolerated, while all whole wheat products should be avoided because of the gluten they contain. With the exception of butter and farmer's cheese, all cow milk products should also be avoided. Legumes are not an important part of your diet and are more likely to cause problems because of the lectins they contain.

Blood type diet: do our red blood cells clump together?

If anyone makes such a claim - and publishes it in a book destined for the New York Times bestseller list designed to change the diet of a nation - he or she has a duty to back up the claim with solid scientific evidence. D'Adamo repeatedly fails to do this. In order to make his "lectin goblins" anywhere near credible, he would have to publish microscope photos with muscle tissue samples from people of blood group 0, A, B and AB after they had eaten kidney beans or lentils. The recordings should clearly show lectin deposits in the muscles of Group 0 people - in contrast to the unstressed muscle tissue samples of blood group A. If an author cannot provide this kind of evidence, it is hardly responsible to make claims that have millions of Scare people about eating legumes and other valuable foods that are rich in protein and fiber. Indeed, for a single person, it may be best not to eat a particular legume. The reasons for this, however, are nutritional-physiological causes such as allergies or individual intolerances and not the blood group.

What makes the "blood group" theory completely implausible is D´Adamo's claim of immediate physiological damage: Lectins are supposed to make the red blood cells of members of certain blood groups stick together (agglutinate) that are "genetically / evolutionarily unsuitable" for such foods. Agglutination means that the red blood cells stick together and form clumps. Once they have clumped together, they will not come off again. This causes cells and tissues to die, is harmful to health and can even lead to death. This is because red blood cells transport oxygen to the cells of vital tissues such as the brain, heart and kidneys. To carry out this transport, they have to flow through tiny vessels (capillaries) that are so narrow that the blood cells can only pass through one at a time. When the red blood cells stick together from lectins or something else, they clog the capillaries and block the blood flow. The blood is prevented from delivering the life-sustaining charge of oxygen to the tissues supplied by these capillaries.

Blood group A type: The farmer

The second oldest blood group originated in the Neolithic Age, when people began farming and raising livestock. A-types have a tolerant immune system and a sensitive gastrointestinal tract. That is why a vegetarian diet, in which fruit and vegetables play an important role, is particularly digestible. A-types can eat small portions of fish several times a week. With the exception of small amounts of fermented milk products such as yogurt and kefir, you should avoid cow's milk products. The same applies to almost all wheat products. With a few exceptions, most legumes are digestible for this blood group.

Most people don't know their blood type, let alone know which foods are "evolutionarily unsuitable" for them. It can therefore be assumed that many eat "wrong foods" for their blood type. Group 0 people should e.g. B. do not tolerate wheat and members of group A do not tolerate meat. The brain, heart, lungs, kidneys and adrenal glands of these people would soon be irreparably damaged, and the outcome could be fatal for millions. Such micro-infarcts caused by lectins would be as well known to pathologists and other medical professionals as arteriosclerosis is today. The pathology textbooks contain clear descriptions - completed with microscopic images of damage caused by lectin deposits and blood agglutination in the most important organ systems. In fact, such observations are completely unknown in research.

Wheat taboo for blood group 0

If you read such a generalizing statement as "Blood group 0 absolutely does not tolerate whole wheat products", you have to ask: What does the author mean by "absolutely"? Do Group 0 people instantly fall to the ground, hold their stomachs, and vomit after eating a wheat cracker - or worse, do they get instant brain damage from the sticky blood cells in their brains? How much wheat can blood group 0 tolerate before the blood agglutinates? A roll, a noodle? Sure, some people may experience discomfort when they eat wheat. But they do this because of a wheat allergy (e.g. gluten intolerance) or other verifiable mechanisms - not because of lectins. It is true that wheat can also be a problematic food for people with chronic bowel inflammation (ulcerative colitis). You should avoid wheat. Lectins may also affect the inflammation in some patients. But before you tell millions of people with blood group 0 - more than 40 percent of the world's population - that they should never eat whole wheat, wouldn't convincing scientific evidence be required?

Blood group B-Type: The balanced one

This blood group arose around 15,000 years ago as a result of changed climatic conditions and the mixing of ethnic groups. The B-type is particularly adaptable and has a robust digestive tract and a strong immune system. He can choose from most foods and also consume dairy products. Poultry, wheat and rye products are difficult to digest for him. Most vegetables and fruits are well tolerated by blood group B, while the legumes are only a few.

To substantiate his claim about harmful lectins made from wheat, D'Adamo would need to show recordings of intestinal tissue from Group 0 people who recently ate wheat. There should be clear signs of clumps that impair the function of the intestinal cells. D'Adamo would have to provide images of tissue samples of the remaining blood groups, in which the intestinal wall would be visibly undamaged and much less contaminated with lectin deposits than those of blood group 0. However, intestinal inflammations such as ulcerative colitis, Crohn's disease and gluten intolerance occur in all blood groups - and D'Adamo does not provide convincing evidence to the contrary.

Milk is not for A types?

D'Adamo also makes unbelievable statements about dairy products, some of which he attributes to lectins: "When a person with blood group A drinks milk, their organism immediately begins the agglutination process to ward them off." For this phenomenon, too, he shows neither microscopic photographs nor other credible evidence. He would also have to explain why (sometimes enormous amounts) milk-drinking group A people do not suffer strokes and embolisms, even though their blood supposedly agglutinates throughout the vascular system. He does not provide any evidence or plausible explanations for this - very annoying in a book that presents itself as scientific.

This post is
in the UGBForum,
published by the specialist magazine for sustainable nutrition.

The American doctor also explains, "People with blood group B are the only ones who can enjoy a wide variety of dairy products without worries. This is because the primary B-type sugar is D-galactosamine, the sugar that is also contained in milk ". In reality, the main sugar in milk is not D-galactosamine, but lactose. Even if there were significant amounts of D-galactosamine in cow's milk, the blood of people with blood group A would not clump. Because, according to recognized medical knowledge, the A-blood does not stick together due to the D-galactosamine alone, but only in combination with a molecule of the sugar fucose (e.g. contained in breast milk and vegetable gum). Certain people - regardless of their blood group - will certainly react to cow's milk and other dairy products. There are various reasons for this, but not because certain sugar components from milk stick to the "wrong" blood cells of these people.

Blood group astrology

D'Adamo's prejudices against vegetarians are almost discriminatory. In the book he says that the meat-eating blood group 0 has a "genetic memory of strength, endurance, self-confidence, boldness, intuition and innate optimism". 0 types are "the epitome of energy", "tough and strong, stimulated by a protein-rich diet". He describes the "rather vegetarian" group A as obsequious tofu eaters, "biologically susceptible to heart disease, cancer and diabetes". He describes the group A personality as "poorly suited for intense, stressful leadership positions in which group 0 people shine". He claims that under pressure they are "worried, paranoid and take everything personally". In this way D'Adamo creates a kind of "blood group astrology" that forces complex people into strange clichés.

Blood group AB type: The enigmatic

The "modern" AB type emerged from a mixture of blood groups A and B within the last 1000 years. It has a sensitive digestive tract and an overly tolerant immune system. The only blood group that AB types can tolerate is wheat products. In the case of legumes, the digestible and the indigestible varieties are roughly in balance. Almost all vegetables and fruits that are well tolerated by the A or B type are also recommended for the AB group. Sour milk products and most types of cheese and fish are also well tolerated, while meat should only be eaten in small quantities.

It should also be borne in mind that the A-B-0 blood group system used by Dr. Landsteiner worked out around 1920, is just one system among many, such as B. the rhesus system. All of these systems are based on proteins on the cell surface to determine blood groups. This means that certain foods would be right for the A-B-0 blood type system, but absolutely wrong for any of the other systems. Why should the D-galactosamine-fucose molecules on the surface of the red blood cells, which are decisive for the A-B-0 blood group system, be the decisive ones?

Blood group diet: Everything an evolution fairy tale

D'Adamo invented an evolution fairy tale that leaves many questions unanswered. What exactly does he think happened to the Group 0 hunters-and-gatherers when Group A people started planting wheat, barley, and other crops? Did Group 0 people immediately fall into the dust, incapable of work and reproduction, if they ate a little barley? Was it why they became bellicose and beat the peasants to death because lectins strained their intestines? Or did the Group A people show up after the crops were grown because the people with blood group 0 died out because of their blood clotted in their brains?

Since most of the people in the world (over 40 percent) belong to blood group 0, many of us are no longer allowed to eat wheat. D'Adamo recommends that this group ensure that they have sufficient protein intake and that they consume portions of meat of up to 120 grams per meal. Regardless of how one evaluates D'Adamo's recommendations from a nutritional and physiological point of view: From an ecological point of view, a meat-based diet cannot be achieved for the world population and is unsustainable even for a sizeable minority. Soils, water and forests on earth would be reduced to the production of a meat-rich diet. We are already destroying our own livelihoods on our planet for a little bit of meat. Promoting a meat-centered diet increases the risk of ecological disasters and threatens the future of all of us. We owe it to ourselves, our children and all descendants to find out how to achieve optimal organ function and long life. With forms of nutrition that are truly sustainable - for the individual, for society and for the planet.

Blood type diet: Don't be afraid of legumes

Lectins, also called hemagglutinins, are found in many plant foods. Potatoes, wheat and especially legumes such as kidney beans, soybeans or lentils contain these special proteins. Some of them are toxic and can irritate the lining of the intestines and cause the blood to clot. Cooking in boiling water will destroy the lectins after just 15 minutes. In sprouted legumes, the lectin concentration is reduced by more than 90 percent, depending on the type of legume and the germination time. Food toxicologists therefore assume that the consumption of legumes in the usual preparation form is harmless. Legumes have the highest protein content among plant-based foods. Most varieties contain almost no fat, but plenty of fiber, which makes them an optimal food for a healthy diet.

Source: Klaper, M .: UGB-Forum 1/01, p.6-9

Slightly changed version of the article: KLAPER, M .: Challenge for a plant-based diet in the nineties: The "Blood group diet". vegi-info 3, pp. 11-14, 2000, reprinted with the kind permission of the Swiss Association for Vegetarianism (SVV).

This article is taken from the UGB archive.

We would like to point out that the content may have to be re-evaluated due to new scientific findings.