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STUDY: Scientific basis of the blood group diet.
JOURNAL: Tidsskr Nor Laegeforen. 2001 Jun 10;121(15):1838-9. Norwegian.
AUTHORS: Poleszynski DV. [PubMed - indexed for MEDLINE]
ABSTRACT: Eat Right 4 Your Type by Peter J. D’Adamo describes a strategy of adapting lifestyle and nutrition to each individual’s physiology and biochemistry. The author’s theory is based on research within, amongst others, physical anthropology, neurology, biochemistry, nutrition, lectinology, epidemiology, psychology, immunology and genetics. Going through the literature shows that Doctor D’Adamo can be mistaken on certain points, and is vague on others. Nonetheless, his general theory seems to be based on scientific studies, and reports show that it works. “Helsevesenet” - the Public Norwegian Health Institutions - should start using the parts of the theory that are based in fact, and the medicinal circles should do more testing and align the theory with basic medicinal science and clinical research.
35,000 examples of Eat Right 4 Your Type have been printed in Norway. [Btw: the country only has a population of 4 million] The book has been complimented by laypersons and ‘natural therapists’ and is rejected by others (2).
The theory is based on five elements:
- an evolutionary perspective of the human being, including a theory on how the blood types evolved, based on the ABO-system.
- Proved relationships between blood types and physical and psychological diseases, used to explain the blood types’ geographical distribution, degrees of risk factor, and strategies for reducing risk.
- Lectins in food can influence [ones] state of health. They can have positive and negative biological effects, i.e. some can be the source of illness, while others can be used therapeutically.
- Existing relationships between genes, like blood type and/or type of tissue, combined with secretor status (Lewis a/b) and other physiological and biochemical variables make it possible to identify an individual’s genetic “fingerprint”.
- Genotyping can, among other things, be used to predict what foods one tolerates and how one handles stress.
Eat Right 4 Your Type has been criticized for being categorical (2). The Literature list is sparing (1). An article of 1980 explains the background (3), an other from 1990 gives documentation on lectin activity (4), and in January 2001 a new, better documented, book came out (5).
Evolution and Blood Types: The fact that primates have the same A- and O- blood type antigens is taken to mean that we have inherited them from common ancestors (2). This can seem logical, since our earliest ancestors were vegetarian, and the hominids on a higher level of evolution were the first to become meat eaters. However, research on the genetic sequences of primates and humans tend to corroborate that ABO genetic polymorphism in primates is a result of convergent evolution, i.e. unrelated mutations, and are not the result of a common genetic origin (6).
Historically, populaces have eaten food that is perceived as adverse for their blood type, e.g. Inuits who are blood type A (meat and fat) and American Indians, blood type O (corn and potatoes). Native populations on “civilized food” usually develop a range of new chronic disorders (7). We do not know what role the blood type can play in differences in peoples state of health.
Blood Type and Illness: Links between blood type and illness have been known for over 80 years, is well documented (8), and is discussed in manuals in genetics (9). Among significant relationships show the odds ratios (OR) for cancer, shows an [over frequency???] in Type A compared to Type O of 1,11 (colon and rectum), to 1,64 (salivary gland). A large study of stomach cancer (N=55,434) shows an OR for type A = 1,22 compared to type O. Contrariwise, in Type O there is a higher rate of cancer of the small intestine (OR 1,35), ulcers (OR 1,53), or bleeding ulcers (OR 1,46) compared to type A, while type A has more eosinophilia (OR 2,38) and tromboemboli (OR 1,61). Differences in the propensity for infection (8) can explain geographical differences in the ratios of blood types. H. Pylori gives a high frequency of ulcers in Type O, who also have a high frequency of disbiosis caused by Candida Albicans (1,8)
Lectins in Illness and in Health: Lectins, in groups (glyco)proteins, bind irreversibly to carbohydrates and are used by plants as defence against being eaten by animals, and as intercellular communication signal substances. After this group of substances were characterised in 1888 (10) over 1,000 foods have been found to contain lectins with biological impact. [The various biological effects] depend on, amongst other factors, the number of binders - those with only one [binder], for example, cannot agglutinate cells. Biological effects from experiments carried out on humans and 14 different types of animals are known (12). Lectins in barley, wheat, potato, rice, rye, tomatoes, and a number of legumes can agglutinate erythrocytes in humans of all blood types. Lectins can have effects resembling those of insulin on fat cells, hinder growth of cancer cells, induce clotting of blood plates and increase the secretion of histamine.
Blood type influences biological variables: Certain people produce more digestive acids than others and are more susceptible to ulcers and heartburn. People of type O seem to produce more digestive acids than those of blood type A, and a variety of enzyme activity in the blood and the intestines vary depending on blood type (5). This is valid for alkaline phosphatase, monoaminoxidase and dopamine-beta- hydroxsylase. A probable reason for this is that the genes that code for proteins and are located near the blood type gene on chromosome 9Q34 is influenced by this.
Blood type and personality: A range of sources link blood type to personality, and the extent of risk for mental disorders (5). It has been substantiated that there is a high degree of polymorphism between receptors and transporters of dopamine and serotonin and a relationship between blood type and stress. One study shows that those of blood type O secrete less cortisone after donating blood than do those of type A (5). Since hard physical effort releases stress hormones, it is quite likely that individuals of type O can tolerate [intense, physical] exercise better than type A’s (1,5).
Conclusion: The ABO-system, secretor status and other systems (MN, Rh) sheds light on the disposition for illness. Lectins in food affect our health, and the blood type gene influences near by genes. Interactions between blood type and environment can probably explain why some get sick while others remain healthy through a long life.
1. D'Adamo PJ, Whitney C. Blodtypedietten. Spis riktig for din blodtype. Oslo: Wem 3 A/S, 1999.
2. Moen T. "Blodtypedietten" - vitenskap eller fantasi? Tidsskr Nor Lægeforen 2001; 121: 355 - 8.
3. D'Adamo PJ. Diet, disease and the ABO bloodgroups: a review of the literature. Seattle, WA: John Bastyr College of Naturopathic Medicine, 1981. www.dadamo.com/literature/lrc.htm (3.2.1999).
4. D'Adamo PJ. Gut ecosystem dynamics III. Lectins and mitogens. Townsend Letter for Doctors & Patients 1990; 85 - 6: 528.
5. D'Adamo PJ, Whitney C. Live right for your type. New York: G. P. Putnam's Son, 2001.
6. Kermarrec N, Roubinet F, Apoil PA, Blancher A. Comparison of allele 0 sequences of the human and non-human primate ABO system. Immunogenetics 1999; 49: 517 - 26.
7. Price WP. Nutrition and physical degeneration. 10. utg. Pasadena, CA: The Price-Pottenger Nutrition Foundation, 1979.
8. Mourant AE, Kopec AC, Domaniewska-Sobozak K. Blood groups and diseases. A study of associations of diseases with blood groups and other polymorphisms. Oxford: Oxford University Press, 1978.
9. Vogel F, Motulsky AG. Human genetics. Problems and approaches. 3. utg. Berlin: Springer-Verlag, 1997.
10. Pusztai A, Bardocz S, ed. Lectins. Biomedical perspectives. London: Taylor & Francis, 1995.
11. Liener IE, Sharon N, Goldstein IJ, red. The Lectins: properties, functions, and applications. Orlando, FL: Academic Press, 1986.
12. Van Damme EJM, Peumans WJ, Pusztai A, Bardocz S. Handbook of plant lectins: properties and biomedical applications. Chicester: John Wiley & Sons, 1998.
COMMENTARY: I wish to thank Katrina (a particpant on the Bulletin Board) for this translation from the original article which appeared in Norwegian.
Perhaps my only problem with the article is that it holds the simplicity of my first book, Eat Right 4 Your Type, somewhat against me, even though the author references far more technical scientific articles that I've written that actually precede its publication. One cannot do two things simultaneously: You can write simplified books for the general public or technical works for scholarly journals. They must be evaluated differently, as they have widely different aims.
Nonetheless, I am gratified that the blood group diet theory is becoming the subject of a more serious scholarly interest, although perhaps despite its success in the mass-market, rather than because of it.