The description of the blood group diet has a purely informative purpose; the author dissociates himself from any theory on the matter and limits himself to a comment contained in the last paragraph.
Generality
What is the blood group diet?
Blood group theory
Conceived and promoted by the Italian-American naturopath Dr. Peter D'Adamo, this diet is based on the theory that the blood group can heavily affect the relationship between food and metabolism.
Diet
Fundamental principles
Importance of evolution and blood group
The creator of this diet starts from the assumption that the differentiation of blood groups in the human being took place during the course of Darwinian evolution.
In some ways, the blood group should represent the genetic trace of an innate predisposition towards a certain type of diet, behavior and motor activity (including sport).
Role of lectins
According to D'Adamo, in some foods there are particular proteins, called lectins, able to influence differently the various blood groups (A, B, AB and 0).
NB . Lectins are NOT lecithins (a mixture of phospholipids contained mainly in soy and in egg yolk with emulsifying properties), but of proteins.
Each person, in relation to their blood type, proves intolerant towards some lectins.
These peptides, once introduced into the body through food, would be able to attack red blood cells "agglutinating them" (a term usually used for the specific reaction of agglutinin antibodies).
According to D'Adamo, taking these "enemy" lectins with the diet is equivalent to undergoing a small transfusion from a donor with a different blood type.
This damage would explain the epidemic of food intolerances and disorders related to certain dietary choices.
This is how - from the pages of his first book "Eat Right 4 Your Type", published in 1997 - Dr. D'Adamo makes a real appeal to the whole world:
"Follow my blood group diet and digestive problems, exhaustion and even some chronic ailments will be just a memory."
What to eat
For the reasons we have described above, according to D'Adamo, to set up a healthy and effective diet it is necessary to take into account the blood group, to modify certain variables respecting their physiological inclinations.
Let's see how.
Differences between blood groups
Blood group 0
Group 0 is the progenitor of the various blood groups.
It is typical of hunters, characterized by an athletic physique and a strong predisposition to foods of animal origin (meat).
These subjects would therefore benefit from the so-called high-protein and ketogenic diets, such as the Paleodieta.
Dairy products, legumes, cereals and derivatives such as bread, pasta, rice, beans, chickpeas etc. are not recommended.
Subjects with zero blood group would have a greater tendency to celiac disease.
Just like the real primitive hunters, these people should regularly carry out heavy physical or sporting activities, characterized by the massive commitment of strength and speed of short duration.
Blood group A
Group A is typical of farmers.
In the evolutionary history of man this sustenance activity has appeared late, but has led to a radical change in the collective diet.
Blood group A carriers benefit from a diet rich in plant foods, including vegetables, fruits, cereals, legumes and pseudocereals (other grains); meat consumption should be limited.
They too must avoid dairy products.
Starting from the assumption that the farmer "should be" a less heavy job than the hunter, it is advisable to associate to the diet a significant amount of "relaxing" or otherwise not too demanding physical activity (golf, yoga, etc.).
Blood type B
Group B characterizes the nomadic populations.
The main characteristics of these populations are the very strong immune system and a potentially effective digestive system.
These people should be the only ones who can safely consume dairy products.
The only foods advised against are those rich in preservatives and simple sugars.
Given the tendency to frequent shifts, during which there is much time to think, light physical activities with an important mental component, such as tennis and walking, would be more suitable.
Blood group AB
finally, the AB group is described as "the enigmatic" and is on the highest step of the evolutionary scale.
From the dietary and sports point of view, the enigmatic is placed halfway between group A and group B. He can therefore consume all foods in moderation, without overdoing dairy products.
Comment
The blood group diet is a food system based on incorrect, incomplete or misrepresented principles.
Let's be clear: what are blood groups?
As explained in detail in the article "the blood group", for over a century it has been known that there are four different blood groups, called A, B, AB and 0 respectively.
- The carrier of the AB blood group is the most fortunate given that, being devoid of specific antibodies, it can possibly receive blood from donors of types A, B, AB and 0 (for this reason, it is called a universal receiver).
- The opposite is true for those with group 0, who can only receive blood of the same type, but can donate it to everyone (universal donor).
- The individual of group A can instead receive blood from groups A and 0, while type B blood is compatible only with groups B and 0.
If these combinations are NOT respected, the antibodies present in the plasma (agglutinins) attack the red blood cells of the transfused blood, neutralizing them (agglutination reaction) and forming small lumps that occlude the blood vessels causing very serious damage to the body.
Is the blood group diet a well-founded system?
The problems for the blood group diet begin when one goes on to examine its scientific assumptions in greater depth.
Does it make sense to demonize lectins?
Based on the results of some independent, published and recognized studies, the various types of lectins are contained simultaneously in the vast majority of foods, and would therefore not be able to selectively attack only one blood group.
Furthermore, the activity of these substances is very often null and the fact that they can bind to the cells does not automatically mean that they can give agglutination.
can there be consequences?
Importance of dairy products : without disturbing illustrious scientists and theories incomprehensible to non-experts in the field, to dismantle the alleged benefits of the blood group diet, just think for a moment about the prohibition of consuming dairy products (except for group B, which in Italy only represents 8-10% of the population).
As everyone knows, dairy products are rich in calcium, a mineral whose diet is often poor and whose deficiency predisposes the subject to osteopenia and osteoporosis.
Too many meat proteins : subjects with blood group 0, in addition to a low-dairy diet, are advised to take a lot of protein with food.
Given that a diet too rich in these nutrients can promote the loss of calcium with urine, following the advice of Dr. D'Adamo it is possible that in the long run the calcium deficiency will worsen.
However, not all authors agree that the high-protein diet is a risk factor for osteoporosis, given its positive effect on intestinal calcium absorption and on the secretion of osteo-anabolic hormones, such as IGF-1.
Fiber excess : the same can be said for subjects belonging to blood group A; the excessive consumption of fibers in fact hinders the absorption of calcium, already strongly compromised by the absence of dairy products in the diet (see diet and osteoporosis).
Calcium deficiency and goat's milk!
To remedy these dietary deficiencies, D'Adamo suggests and encourages all consumption of goat's milk and derivatives.
Other consequences of the blood group diet
The excessive limitation of the animal products suggested to group A could also cause iron, vitamin B12 and omega 3 fats deficiencies.
The coup de grace comes from statistical studies that blatantly disprove the theories of this diet.
Since the subjects of group B can safely consume dairy products, the incidence of milk intolerances is expected to be lower among the people belonging to this blood group.
Too bad that this hypothesis is not confirmed in any way by the statistical data currently available.
We only hope that in a few millennium the supporters of this diet will not end up recommending a new blood type S (sedentary) born in the twenty-first century, a diet rich in fatty foods, alcohol and simple sugars, associated with the sedentary lifestyle typical of their ancestors lived at the beginning of the third millennium.
