Blood type diet
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The blood type diet is a nutritional diet advocated by Peter D'Adamo, outlined in his book Eat Right 4 Your Type. D'Adamo claims that ABO blood type is the most important factor in determining a healthy diet and recommends distinct diets for each blood type.
Throughout his books, D'Adamo cites the works of biochemists and glycobiologists who have researched blood groups, claiming or implying that their research supports this theory. The consensus among dietitians, physicians, and scientists is that the theory is unsupported by scientific evidence.
D'Adamo's premise is that blood type is key to the human body's ability to differentiate self from non-self. Lectins in foods, he asserts, react differently with each ABO blood type and, to a lesser extent, with an individual's secretor status. In "Lectins: The Diet Connection" and subsequent chapters of Eat Right 4 Your Type, lectins which interact with the different ABO type antigens are described as incompatible and harmful, and that the selection of different foods for A, AB, B, and O types is therefore important in minimizing reactions with these lectins.
D'Adamo bases his ideas on the ABO classification system of Karl Landsteiner and Jan Janský, as well as some of the many other tissue surface antigens and classification systems, particularly the Lewis antigen system for ABH secretor status.
On page 20 of Eat Right 4 Your Type, D'Adamo states, "At this point, you might be wondering about other blood type identifiers, such as positive/negative, or secretor/non-secretor. ... These variations or subgroups within blood types play relatively insignificant roles. More than 90% of the factors associated with your blood type are related to your primary blood type, O, A, B, or AB."
The evolutionary theory of blood groups 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 1950 book Genetics and the races of man: An introduction to modern physical anthropology, Boyd describes how through genetic analysis of blood groups, modern humans can be categorized into populations that differ according to their alleles. Boyd divided the world population into 13 geographically distinct species 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 described by D'Adamo as the hunter. He recommends that those of this blood group eat a higher protein diet. The group is alleged by D'Adamo to be the first blood type and to have originated 30,000 years ago, although research indicates that blood type A is actually the oldest.
- Blood group A is called the agrarian or cultivator by D'Adamo, who believes this type dates from the dawn of agriculture, 20,000 years ago. He recommends that individuals of blood group A eat a diet that emphasizes vegetables and is free of red meat, a diet more closely vegetarian.
- Blood group B is called the nomad by D'Adamo, who estimates this group to have arrived 10,000 years ago. He states that this type is associated with a strong immune system and a flexible digestive system. He also asserts that people of blood type B are the only people able to thrive on dairy products; this is contradicted by the fact that while people with blood type B tend to be from Asia (specifically, China or India), lactose intolerance is most common among people of Asian, South American, and African descent and least common among those descended from northern Europe or northwestern India.
- Blood group AB is described by D'Adamo as the enigma, who believes it to be the most recently evolved type and to have arrived less than 1,000 years ago. In terms of dietary needs, he treats this group as an intermediate between blood types A and B.
Scientific criticism 
Research evidence 
One criticism is that he provided inadequate evidence; his first book, Eat Right 4 Your Type, published in 1997, contains only a bibliography. Although his subsequent books have provided thorough references for the classifications of various foods within his categories of "beneficials", "neutrals", and "avoids", his specific process and reasons for reaching these conclusions of classification remain undocumented.
By restricting the complex processes of the human body to just four limiting stereotypes, the blood type diet has been described as "blood type astrology".
There is a lack of scientific evidence supporting the associations between disease states and ABO blood types as mentioned on Peter D'Adamo's website. A search of PubMed under the author's name does not yield any peer-reviewed articles with data to support his claims. For example, his claim that elderberry can be used as a remedy for the common flu lacks scientific evidence and may be misleading. A review article by Dr. Guo and colleagues, published in the American Journal of Medicine, reports that "the effectiveness of any complementary and alternative therapy for treating or preventing seasonal influenza is not established beyond reasonable doubt. Current evidence from randomized controlled trials is sparse and limited by small sample sizes, low methodological quality, or clinically irrelevant effect sizes."
Questions of lectin actions 
D'Adamo claims many ABO specific lectins exist in foods. This claim is unsubstantiated by established biochemical research, which has found no differences in the reactions of lectins with human ABO types. Research shows that lectins specific to a particular ABO type are generally not found in foods (with several rare exceptions, e.g., the Lima bean) and that lectins with ABO specificity are more frequently found in non-food plants or animals.
A study by The American Journal of Clinical Nutrition that has been cited to support D'Adamo's theories reported that the edible parts of 29 of 88 foods tested, including common salad ingredients, fresh fruits, roasted nuts, and processed cereals, were found to possess significant lectin-like activity (as assessed by hemagglutination and bacterial agglutination assays). However, nearly all of the 29 foods agglutinated red blood cells of all ABO blood types and were not type-specific; D'Adamo's theory refers to lectins in food that react to specific ABO blood types.
D'Adamo has remarked in the past that it is an oversimplification of his work with blood groups to simply apply the lectin-blood group specifics ad hoc to his work, since that "would not be following the Blood Type Diet, but rather a lectin-avoidance diet".[this quote needs a citation] He states that the Blood Type Diet is characterized more by "what you eat rather than what you avoid", and that "the lectin connection was only a part of a much larger picture."[this quote needs a citation]
Lack of clinical trials 
The Blood Type Diet has been criticized for its lack of support by clinical trials. In Eat Right 4 Your Type, D'Adamo mentions the diets being in the eighth year of a 10 year cancer trial, but the results of this trial have never been published. In his book Arthritis: Fight It With the Blood type Diet, D'Adamo mentions an impending clinical trial of the Blood Type Diet to determine its effects on the outcomes of patients with rheumatoid arthritis, but the results of this 12 week trial have also never been published.
Blood type evolution issues 
Luiz C. de Mattos and Haroldo W. Moreira point out that D'Adamo's assertion that the O blood type was the first human blood type requires that the O gene have evolved before the A and B genes in the ABO locus; phylogenetic networks of human and non-human ABO alleles show that the A gene was the first to evolve. They argue that it would be extraordinary, evolutionarily, for normal genes (those for types A and B) to have evolved from abnormal genes (for type O).
Yamamoto et al. further note:
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.
Another study from 2004 concluded that "[a]ssuming 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"; D'Adamo asserts that the ABO blood types emerged between 30,000 and 1,000 years ago.
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) (2002). The Eat Right 4 Your Type Complete Blood Type Encyclopedia. Riverhead. ISBN 1-57322-920-2
See also 
- Dr Arpad Pusztai (March 29, 2001). "Reply from Dr. Arpad Pusztai about Sialic Acid". Retrieved 2011-09-10.[unreliable medical source?]
- P. J. D'Adamo. Eat Right 4 Your Type (Human Blood Cells (Consequences of Genetic Polymorphisms and Variations), Chapter 2: ABO POLYMORPHISMS AND THEIR PUTATIVE BIOLOGICAL RELATIONSHIPS WITH DISEASE ed.). p. 44. "As it is not possible to comparatively re-interpret all of the published data, we have tried to present this data with a reasonably "open mind", so that you may "find your own truth". However, it must be stated that an "open mind" should not extend to some of the non-scientific literature where there are books on the ABO system of pure fantasy. 206 The most recent and incredulous of these claims that individuals of each ABO blood type must subscribe to a specific diet in order to stay healthy, live longer and achieve an ideal weight!"[non-primary source needed]
- [http://www.aarpmagazine.org/health/dr_debunker_blood_type_diet.html[dead link] "AARP: Dr. Weil, "Does the Blood Type Diet really work?""].
- Juliette Kellow, BSc RD, Dietitian. "The Blood Type Diet under the spotlight". Retrieved 2011-09-10.[self-published source?]
- "The Blood Type Diet: Fact or Fiction?". KeepTheDoctorAway. Archived from the original on 2010-08-04.[unreliable medical source?]
- "Blood type diet: Any health benefits?". Mayo Clinic. Archived from the original on 2011-05-15.
- Michael Klaper, M.D. "The Blood Type Diet: Fact or Fiction". www.EarthSave.org. Retrieved 2011-09-10.[self-published source?]
- http://www.mja.com.au/public/issues/175_12_171201/roberts/roberts/html[dead link]
- "The Individualist". Retrieved 2011-10-17.
- Saitou, Naruya; Yamamoto, Fumi-ichiro (1997). "Evolution of Primate ABO Blood Group Genes and Their Homologous Genes". Molecular Biology and Evolution 14 (4): 399–411. PMID 9100370.
- Praveen K Roy (16 June 2011). "Lactose Intolerance". eMedicine. Retrieved 23 November 2011.
- Dean, Laura (2005). Blood Groups and Red Cell Antigens. Baltimore, MD, USA: National Center for Biotechnology Information (NCBI), National Library of Medicine, National Institutes of Health (NIH). Retrieved 23 November 2011.
- Robin, Suzanne (28 March 2011). "Blood-type Diet". LIVESTRONG.COM. Lance Armstrong Foundation. Retrieved 23 November 2011.
- P.J. D'Adamo. "Blood Type Diet: Criticisms and Frequently Asserted Objections". Retrieved 2011-09-10.
- Michael Klaper, M.D. (November 11, 2005). "The "Blood Type Diet": Fact or Fiction?". Toronto Vegetarian Association. Retrieved 2011-09-10.
- Metabolic and Immunologic Consequences of ABH Secretor Status[non-primary source needed]
- Guo, R; Pittler, MH; Ernst, E (2007). "Complementary medicine for treating or preventing influenza or influenza-like illness". The American Journal of Medicine 120 (11): 923–929.e3. doi:10.1016/j.amjmed.2007.06.031. PMID 17976414.
- D'Adamo, P. (1996). Eat Right 4 Your Type. Putnam. ISBN 0-399-14255-X, pg 23, Lectins: the diet connection
- Els J.M. Van Damme, Willy Peumans, Arpad Pusztai, and Susan Bardocz. The Handbook of Plant Lectins: Properties and Biomedical Applications. New York, John Wiley & Sons, 1998.[page needed]
- Sharon A, Sathyananda N, Shubharani R, Sharuraj M: Agglutination of Human Erythrocytes in Food and Medicinal Plants, Database of Medicinal Plants, published by the Karnataka State Council for Science and Technology, May, 2000.[page needed]
- Nachbar, MS; Oppenheim, JD (1980). "Lectins in the United States diet: A survey of lectins in commonly consumed foods and a review of the literature". The American journal of clinical nutrition 33 (11): 2338–45. PMID 7001881.
- "Questions of lectin actions". Retrieved 2011-10-17.
- D'Adamo, P. (1996). Eat Right for your Type. Putnam. ISBN 0-399-14255-X, pg 307, "I am beginning the eighth year of a ten year trial on reproductive cancers, using the Blood Type Diets. My results are encouraging. So far, the women in my trial have double the survival rate published by the American Cancer Society. By the time I release the results in another 2 years, I expect to make it scientifically demonstrable that the Blood Type Diet plays a role in cancer remission."
- D'Adamo, P., Arthritis: Fight it with the Blood Type Diet (2004) ISBN 0-399-15227-X, pg 300,"IFHI is currently conducting a twelve-week randomized, double-blind, controlled trial implementing the Blood Type Diet, to determine its effects on the outcomes of patients with rheumatoid arthritis."
- Mattos, Luiz C. de; Moreira, Haroldo W. (2004). "Genetic of the ABO blood system and its link with the immune system". Revista Brasileira de Hematologia e Hemoterapia 26. doi:10.1590/S1516-84842004000100012.
- Mourant AE, Kopec AC, Domaniewska-Sobczak K. The distribution of the human blood groups and others polymorphisms. London: Oxford University Press, 1976. 140p.
- Roubinet, Francis; Despiau, Stephanie; Calafell, Francesc; Jin, Fen; Bertanpetit, Jaume; Saitou, Naruya; Blancher, Antoine (2004). "Evolution of the O alleles of the human ABO blood group gene". Transfusion 44 (5): 707–15. doi:10.1111/j.1537-2995.2004.03346.x. PMID 15104652.