The Blood Type Diet
The blood type diet is a diet advocated by Peter D'Adamo and outlined in his book Eat Right 4 Your Type. Its basic premise is that blood type is the most important factor in determining a healthy diet.
The cornerstone of his theory is D’Adamo’s premise that lectins in foods react differently with each ABO blood type. Throughout his books he cites the works of various biochemists and glycobiologists as support for this theory. In his book, Eat Right 4 Your Type, “Lectins: The Diet Connection”, and in following chapters, lectins which interact with the different ABO type antigens are described as incompatible and harmful, ergo the selection of different foods for A, B, and O types to minimize reactions with these lectins.
D'Adamo bases his ideas on the ABO classification of Karl Landsteiner and Jan Jansk�, and some of the many other tissue surface antigens and classification systems, in particular the Lewis antigen system for ABH secretor status. D'Adamo has gathered many references pertaining to blood groups on his website.
The evolutionary theory of blood groups, which is also used by D'Adamo, stems from work by William C. Boyd, an immunochemist and blood type anthropologist who made a worldwide survey of the distribution of blood groups. In his book Genetics and the races of man: An introduction to modern physical anthropology, published in 1950, Boyd describes how by genetic analysis of blood groups, human races are populations that differ according to their alleles. On this basis, Boyd divided the world population into 13 geographically distinct races with different blood group gene profiles.
D'Adamo groups those thirteen races together by ABO blood group, each type within this group having unique dietary recommendations:
* Blood group O is believed by D'Adamo to be the hunter, the earliest human blood group. The diet recommends that these supposedly muscular, active people eat a meat-rich diet along the lines of the Paleolithic diet.
* Blood group A is called the cultivator by D'Adamo, who believes it to be a more recently evolved blood type, dating back from the dawn of agriculture. The diet recommends that individuals of blood group A eat a diet emphasizing vegetables and free of red meat, a more vegetarian food intake.
* Blood group B is, according to D'Adamo, the nomad, associated with a strong immune system and a flexible digestive system. The blood type diet claims that people of blood type B are the only ones who can thrive on dairy products.
* Blood group AB, per D'Adamo, the enigma, the most recently evolved type. In terms of dietary needs, his blood type diet treats this group as an intermediate between blood types A and B.
More About the Blood Type Diet:
Criticism
D'Adamo's Blood type diet has met with many criticisms, some of which are in turn addressed by D'Adamo.
Evidence
One criticism of D'Adamo's hypotheses and recommendations claims that he provided inadequate evidence. For example, his first book, Eat Right 4 Your Type, published in 1997, contains only a bibliography. Most of his subsequent books, however, have been thoroughly referenced as far as his general theory. However, the reasons for the classifications of the foods in his diet remains undocumented.
Another criticism is that even though D'Adamo claims there are many ABO specific lectins in foods, this does not agree with what is found in the scientific literature. In research done by separate and independent groups of biochemists, on lectins in different foods and their reactions with ABO blood type, show that there is no difference in how the lectins react with any human ABO type. Lectins which are preferential for a particular ABO type are not found in foods (except for one or two rare exceptions, i.e. lima bean). Lectins with ABO specificity are more frequently found in Non-food plants or animals.
Another criticism is that there are no clinical trials of the blood type diet. In his first book ER4YT, D'Adamo talks about being in the 8th year of a 10 year cancer trial, but no results of this trial have ever been published. In his book "“Arthritis, Fight it with the Blood type diet”, D'Adamo talks about a clinical trial of the Blood Type Diet to determine its effects on the outcomes of patients with rheumatoid arthritis. But no results of this trial have been published.
Blood type evolution
Did the ABO Blood Group evolve as a result of Ancestral Diet or from Chimpanzees?
Some critics of the blood type diet[citation needed] claim that blood type evolution contradicts the premise that selecting a diet based on blood type can improve one's health. Their argument is that the blood types of chimpanzee and projects like the Chimpanzee Genome Project show that blood groups evolved millions of years ago instead of through ancestral diets.
Blood type diet supporters argue however that human ABO blood types were not inherited from chimpanzees because chimpanzee blood group genes are located on their chromosome 11, while human ABO blood group genes are on chromosome 9, and there is evidence that human and primate blood groups emerged independently by convergent evolution. The possibility of genetic linkage between blood types and other features such as morphological characteristics is shown by the detection of such a case of linkage in the rabbit. To demonstrate how individuals of varying blood groups differ in characteristics that relate to polymorphisms in gene expression on loci close to 9q34 (the gene that codes for blood type in humans), D'Adamo cites examples of scientific research into genetic linkage of several genes close to 9q34. For example, the gene coding for the enzyme argininosuccinate synthetase is also on 9q34, and a link with blood type was found due to a poor response to nitric oxide therapy in individuals with blood group B and AB, due to slow recycling of arginine from citrulline during the production of nitric oxide, a polymorphism that may affect L-arginine and L-citrulline signalling functions in the thalamus. Another genetic linkage with ABO is the variation in plasma levels of von Willebrand factor, the reason individuals with blood type A and AB tend to have more thrombotic strokes than hemorrhagic strokes. Further, ABO blood type is closely linked to variation in levels of serum dopamine beta hydroxylase (the enzyme that converts dopamine to norepinephrine, whose gene is on 9q34,), which may reflect alterations in susceptibility to manic depressive illness. [15] Linkage of a breast cancer-susceptibility locus to the ABO locus increases the risk of breast cancer in individuals of blood group A and AB. These linkages have not been found in chimpanzees.
Is the first ABO blood type A or O ?
In the the article "Genetic of the ABO blood system and its link with the immune system", Luiz C. de Mattos and Haroldo W. Moreira point out that in order to agree with D'Adamo's assertion that the O blood type was the first human blood type to appear, you need to accept that the O gene evolved before the A and B genes in the ABO locus. However, after constructing phylogenetic networks of human and non-human ABO alleles, Saitou and Yamamoto concluded that the A gene represents the ancestral form. Thus, in the evolutionary sense, it is difficult to believe that normal genes like A and B have evolved from abnormal genes like O.
they go on to say:
The three most common O genes identified in different populations are O1, O1v (variant) and O2. Compared to the ancestral form, the O1 and O1v genes have a deletion of a G base in exon 6 (guanine in position 261) and show additional nucleotide differences. The O2 gene does not have the G deletion but has a substitution (G802A) in exon 7, which appears to abolish its function. Although the O blood type is common in all populations around the world, there is no evidence that the O gene represents the ancestral gene at the ABO locus. Nor is it reasonable to suppose that a defective gene would arise spontaneously and then evolve into normal genes.