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BLOOD TYPE DIET Back To Diet Articles  
     

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 ABO blood type is the most important factor in determining a healthy diet. The diet is widely derided by dieticians, physicians, and nutritional scientists as having no scientific basis.

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

blood type diet
blood type diet
 

glycobiologists who have researched blood groups, claiming or implying that their research supports 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 Janský, 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 slightly different frequency distributions of blood group genes.

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

 

 

Criticism
D'Adamo's Blood type diet has met with many criticisms. The fundamental criticisms are first, that none of his hundreds of citations to others' research on blood groups directly support his claims of differential food tolerances, and second, that he provides no comparative clinical trials demonstrating efficacy of his diet.

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 ofpatients with rheumatoid arthritis. But no results of this trial have been published.

BLOOD TYPE DIET

Type A

The Cultivator:

Settled, visionary, analytical.

Strengths:

Adapts well to dietary and environmental variety. System preserves and metabolizes nutrients efficiently.

Weaknesses:

Unable to digest and metabolise meat protein easily. Vulnerable immune system, open to microbial invasion.

Type B

The Nomad

Balanced, flexible, creative.

Strengths:

Strong immune system. Versatile adaptation to dietary and environmental changes. Balanced nervous system.

Weaknesses:

No natural weaknesses. However, imbalance causes a tendency toward autoimmune disease and rare, slow-growing viruses.

Type AB

The Enigma

Rare, versatile, compassionate

Strengths:

Designed for modern conditions. Highly tolerant immune system. Versatile.

Weaknesses:

Sensitive digestive tract. Open to microbial invasion.

Type O

The Hunter

Strong, self-reliant, leader

Strengths:

Hardy digestive tract. Strong immune system. Natural defences against infections. System designed for efficient metabolism and preservation of nutrients.

Weaknesses:

Intolerant to new dietary and environmental conditions. Tendency towards an overactive immune system.

 


Blood type evolution
Is the first ABO blood type A or O ?
In 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.

In May 2004, Transfusion published a study which concluded that: "Assuming constancy of evolutionary rate, diversification of the representative alleles of the three human ABO lineages (A101, B101, and O02) was estimated at 4.5 to 6 million years ago." This suggests that the ABO didn't evolve in the near past, as D'Adamo suggests.

Further reading

  • D'Adamo, P. (with additional material by Catherine Whitney) (1996). Eat Right 4 your Type. Putnam. ISBN 0-399-14255-X
  • D'Adamo, P. (with additional material by Catherine Whitney) (2000). Live Right 4 your Type. Putnam. ISBN 0-399-14673-3
  • D'Adamo, P. (with additional material by Catherine Whitney) (2002). The Eat Right 4 Your Type Complete Blood Type Encyclopedia. Riverhead. ISBN 1-57322-920-2
  • D'Adamo, P. "Nontransfusion Significance of ABO and ABO-Associated Polymorphisms" Chapter 43 In: Pizzorno JE, Murray MT (Eds.) Textbook of Natural Medicine, 3rd Edition, Volume 1 (2006) Elsevier. ISBN 0-443-07300-7
 
 
 
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)  
 
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