"I am afraid that Peter's merits are not estimated enough in the scientific world. Therefore it seems to me necessary, not only to promote his concept here in Europe, but also to tell him that I acknowledge him as one of the most creative scientists in the Western world."

- Professor Gerhard Uhlenbruck, PhD, MD









Response to Various Criticisms

You may have encountered the following criticisms of my work on the web.

Rather than pretend that this type of misinformation will simply 'just go away', I've documented and reviewed some of these articles. I also provide links to the original material, so you can decide for yourself the benefits of this sort of dialogue.

The responses are in most part rhetorical since none these criticisms present any proof for their assertions. Most are ad hoc offerings from acolytes of other dietary systems, fellow diet book authors and individuals who are fiercely opposed to naturopathic medicine.

Keys to evaluating material critical to the Blood Type Theory:

  • Is it science-based, or just the postulations of a spokesman for an opposing system threatened by its conclusions? Is the author opposed to all forms of naturopathic medicine or alternative medicine?
  • Does the critic display a convincing knowledge of the human ABO groups? We've found that many critics of Dr. D'Adamo's work have never actually read any of his books, nor have they taken the time to investigate the science. Is the author of the criticism and expert in the the area?
  • Does the criticism appear fair and balanced? Is the critic curious about what they are investigating? It is OK to be skeptical, but a surprising amount of skeptics have absolutely no curiosity about that which they are skeptical of. Did the critic take the time to do a thorough review of the material?
  • Did the critic address their concerns directly with Dr. D'Adamo prior to writing their review? It is considered good journalistic practice to present concerns directly to the authors of a study or book before completing a review. This prevents misconceptions, encourages dialogue, and allows for a more balanced editorial presentation.  A clear sign of a preconceived, slam-dunk ('Gotcha') review is that no effort is made to afford the other side a chance to state their case.
A few of the more frequently seen criticisms:

 


1.


Title
Dr. Debunker: Does the blood type diet really work?
Link
Link (HTML)
Authors
Weil, Andrew, MD (Tucson, USA)
Distribution
AARP Website, AARP Magazine (Sept-Oct 2008)
Author Qualifications
Dr. Weil is a medical doctor. He has written numerous books on alternative medicine. He has not authored any peer-reviewed scientific papers on blood groups, nutrition or lectins. He has not conducted any clinical research on blood groups and diet.
Criticism Type
Diet Wars (Diet Book Author)
Article Synopsis

"D'Adamo theorizes that the basis for such differences is our reactions to certain food proteins called lectins. Lectins are common in plant foods, especially grains and beans, and may be involved in food allergies and some immune disorders. But there is no convincing evidence for any interactions between lectins and the molecules that determine blood type."

"Yet some people swear the blood type diet has worked for them. There's a reason for that. Making changes in how we eat is not easy. To follow any prescribed dietary program with rules and restrictions represents a significant commitment of mental energy toward self-improvement. That alone can lead to a greater sense of well-being and better health. But if you want to eat a better diet, I recommend you rely on information grounded in nutritional science."




Response


Dr. Weil is a well-known holistic doctor and author of numerous books on diet. In a short article on the AARP online magazine, Dr. Weil again argues that the Blood Type Diet should 'be sacked.'

Jettisoning his previous criticisms, including the rather odd observation that animals have blood types and yet don’t follow the Blood Type Diet, Dr. Weil now offers his opinions on the lack of association between lectins and blood types. Dr. Weil's claim that there are no proven relationships between lectins and the molecules that determine blood type was apparently taken from an incorrect assertion that often finds its way onto the Wikipedia entry on the Blood Type Diet. This is hardly a hard-science resource.

In fact, blood group specificity is listed as one of the nine major factors influencing glycosylation in the gut (glycosylation is the process of manufacturing the sugar molecules that lectins bind with). Other factors include diet, age, animal species, disease and bacterial population. (Trends in Glycoscience and Glytcotechnology; 8:149-165)

Dr. Weil is apparently still ignorant of the secretory differences (digestive enzymes, etc.) between the blood groups, perhaps the most significant reason behind the need for the tailoring nutritional needs to these genetic markers.[1]

Despite his efforts to position himself as the arbiter of that which is 'good' about alternative medicine, Dr. Weil is clearly capable of speaking out of both sides of his mouth. In a reply one of his own critics (Arnold S. Relman, editor-in-chief emeritus of the New England Journal of Medicine)[2], he writes:

"I don't think you can have it both ways; you can't demand evidence, and then when evidence comes in that contradicts your preconceptions, say you aren't going to look at it."

"First, I would ask Dr. Relman please to strike the word 'anecdote' from his medical vocabulary. It is offensive and trivializes important information. If he wants to call the case reports I have published 'uncontrolled clinical observations,' I will not object. Scientific method starts with raw observation, proceeds to hypothesis and then to experiment."

"In my experience-- I consider experience to be one valuable source of data--many patients use alternative methods because they find that they work. And if a patient has tried a method and found that it works, that patient needs no further proof, does not need to read the reports of a randomized, double-blind, controlled trial in a medical journal to be convinced of the efficacy of treatment."

Dr. Weil is woefully ill-informed and would do best to consult the work of William Boyd, who first wrote of the blood type specificity of lectins more than a half centry ago[3] or reviewed the research of Martin Nachbar[4] from the 1980's before making such claims, since he is essentially just plain wrong.  A trip to MEDLINE might have might have also proved helpful.[5], [6], [7]

In an article critical of Dr. Weil written for the New Republic ("A Trip to Stonesville") Relman touched on many of Weil's academic inconsistencies, and concluded that:

"Weil considers himself an authority on almost every field of medicine." [8]

Finally, it could be argued that the possible reason Dr. Weil supplies for why some people swear that the blood type diet has worked for them ("a significant commitment of mental energy toward self-improvement") may well be the exact same reason some people derive benefits from his own books, tapes and recommendations.

D. D'Adamo has replied to this article in one of his blogs.



Notes
  • Did not contact Dr. D'Adamo prior to article
  • Searching MEDLINE for terms "ABO", "Blood", "Groups" and 'Lectins" yields 687 published studies[9]
  • A search on MEDLINE shows that Dr. Weil has not published any peer-review articles on nutrition and genetics.


2.


Title
The Blood Type Diet: Latest Diet Scam
Link
Link (HTML)
Authors
McMahon, John J. ND (Wilton CT, USA)
Williams, Deirdre B. ND (Wilton CT, USA)
Distribution
Extensively cross-posted throughout the internet, principally on vegan websites
Author Qualifications
Both authors are naturopathic physicians. Neither have authored any peer-reviewed scientific papers on blood groups, nutrition or lectins. Dr. McMahon has an undergraduate degree in anthropology.
Criticism Type
Opposing diet theory (veganism)
Article Synopsis


We are naturopathic physicians. We are also vegan as are our children. The practice of naturopathy as originally described by Dr. Benedict Lust includes 'the elimination of... habits such as over-eating, alcoholic drinks and... meat eating'. When we attended the John Bastyr College of Naturopathic Medicine the work of Henry Lindlahr, M.D. was required reading. Dr. Lindlahr defined the philosophy of Nature Cure or naturopathy as favoring a 'strict vegetarian diet' because of the 'morbid nature' of the 'alkaloids of putrefaction' which 'every piece of animal flesh is saturated with.

Peter D'Adamo, N.D. has recently published a popular book in which he encourages a diet based on his interpretation of the ABO blood groups and health. This blood type diet theory encourages daily consumption of animal flesh by people of blood type O and blood type B. Together these two blood types make up between 56% and 69% of population of the United States. Schools of naturopathic medicine have begun to include this theory in their curriculum and our colleagues often recommend a diet including daily consumption of animal flesh to vegan/vegetarian patients of blood type O or B."

The foods we eat contain lectins. Because of how lectins clump (or "agglutinate") other molecules they have the capacity to create health problems for human beings. Botulism toxin has a lectin, ricin, that is so deadly you would never encourage someone to consume it.

Also (regarding lectins), there is evidence that enzymes such as intestinal transglutaminase, secreted in response to certain lectins, repair lectin-induced damages to the microvilli and gut epithelium In so doing these enzymes would inhibit and occasionally eliminate the potential for the chronic intestinal inflammation, bacterial overgrowth and illness ascribed to eating "wrong" for your blood type.


Response


Both Henry Lindlahr and Benedict Lust died in their early 60's. A  recent study of 1200 people who reached the century mark between 1932 and 1952 showed only four were vegetarians. At some point in time, naturopathic medicine, and in some peoples' minds health itself, became strongly associated with a vegetarian diet.  Some individuals within my own profession suggest that I had abandoned the core of naturopathic medicine by advocating good quality meat for individuals of certain blood types.

Getting stuck in a belief system can be a tough place to dwell. Often a good question to ask is, "what does the evidence show?"  Naturopathic medicine developed from the water cure movement of Europe. Theodor Hahn is credited as being the first of the pioneers of this water cure movement to integrate vegetarian dietetic principles. He was convinced that a meat-free diet would prolong life. In fact he was so convinced of the value of a vegetarian diet that he spent a great deal of his professional life writing books and pamphlets on the subject and was the editor of a magazine called The Vegetarian

He died of colon cancer at the age of 59. 

Perhaps his diet some how extended his life and he would have died at an even younger age had he not been a vegetarian. This at least is a quite common argument I have heard repeated by supporters of a vegetarian diet when one of their proponents dies an early death.  Ultimately there is no answer, but it is ironic that the person responsible for integrating a vegetarian diet into what would become naturopathic medicine died so young of colon cancer.

According to Drs. McMahon and Williams, Henry Lindlahr, the  founder of "Scientific Naturopathy" in the United States, "was completely committed to vegetarian diet."  Actually, the opposite is true. In fact it has been stated that Lindlahr often incurred the wrath of militant vegetarians by suggesting that "properly prepared and combined vegetables and meats could be more wholesome than certain bad vegetarian combinations." He wrote that it was not his intention "to make a fetish of vegetarianism." Clearly he was not the strict proponent of this diet that these critics would like to believe.

Dr. D'Adamo is far from the only naturopath advocating a hunter gatherer-type diet for some people. The work of Dr. Ron Schmid, ND in his books Native Nutrition and Traditional Foods Are Your Best Medicine constitute some of the best writings by an ND on the subject. 

There may be a repair mechanism that helps heal the intestinal lining from lectin damage, but that does not constitute an effective argument for their wholesale consumption.  Put another way,  our skin would also eventually heal if we sliced it open with a kitchen knife, but that is not a good reason to cut yourself.

The lectin ricin  is from the castor bean, Ricinis communis, not botulism toxin (as McMahon and Williams state above). Botulism is actually a bacterial toxin, not a lectin, from the Clostridium botuliinum. The rest of the review is a hodgepodge of assertions, with many technical errors, and  leaves us no purposeful way to respond. 

Is it too much to expect a critic with an agenda to be possess a rudimentary level of knowledge in the field they purport to criticize?

 


Notes
  • Did not contact Dr. D'Adamo prior to article


3.


Title
Wikipedia: The Blood Type Diet
Link
Link (HTML)
Authors
Multiple Authors (Open Source Encyclopedia)
Distribution
Wikipedia; entries enjoy high rank with Google search engine.
Author Qualifications
Anybody can add, delete and edit entries on Wikipedia. In general, this leads to fairly high quality content, especially in areas which do not reflect 'pop culture,' such as biochemistry and information technology. However when viewed by experts in their chosen areas, the quality of the work is often found lacking. A quick view of a few entries on subjects  of general public interest will soon disclose, that some individuals tend to take things to a very personal level. Vandalism is also common on Wikipedia.

Often a good idea of the current tone of a Wikipedia article can be gleaned from viewing the talk  page for the entry.
Criticism Type
Well-poisoning (opponents of alternative medicine; naturopathic medicine)
Article Synopsis
quote
It is very hard to provide relevant quotes from the Wikipedia page on the Blood Type Diet since the entry changes almost daily. There is a tendency to highlight negative articles and links about the Blood Type Diet while removing articles and links supportive of the theory. Many of the negative entries are written by people who are self-admittedly opposed to any form of alternative medicine.
Response response

Dr. D'Adamo has addressed his frustrations with Wikipedia in a recent blog.
Notes



4.



Title
The Blood Type Diet: Fact or Fiction?
Link
Link (HTML)
Authors
Michael Klaper, Michael,   MD (Hawaii, USA)
Distribution
Extensively cross-posted throughout the internet, principally on vegan websites
Author Qualifications
The author is a medical doctor.  Dr. Klaper has not authored any peer-reviewed scientific papers on blood groups or lectins.  He has published several books on vegan nutrition, principally for children.
Criticism Type
Opposing diet theory (veganism)
Article Synopsis

One of  Eat Right For Your Type's  most disturbing characteristics is the frightening images that the author calls forth without providing scientific documentation. For example, D'Adamo hangs much of his theory on the action of lectins, proteins found on the surface of certain foods that can cause various molecules and some types of cells to stick together. He blames lectins for serious disruptions throughout the body, from agglutination of the blood cells to cirrhosis and kidney failure (page 24). He even scares the reader about these lectin "boogie men" with the tale of ex-KGB agent Georgie Markov who was murdered with an injection of the ultra-potent lectin, ricin.

To begin to convince me of the existence of his “lectin gremlins,” he would have to publish photographs, taken through a microscope, of muscle tissue biopsied from people with Type O, Type A, Type B, and Type AB blood after they have eaten kidney beans and/or lentils. The photographs should clearly show the lectin deposits in the muscles of people with Type O blood - and not in the tissue samples from the muscles of people with Type A blood.

Remember, there is nothing sacrosanct about the ABO blood typing system devised by Dr. Landsteiner in the 1920's. It is only one system classifying more than thirty proteins on the surface of cells that determine other blood groups, with names like Auberger, Diego, Duffy, I, Kell, Kidd, Lewis, Lutheran, MNSs, P, Rh, Sutter, and Xg. This means that food selections that may be "right" for the ABO blood group system might be "dead wrong" for someone's Kell or Kidd antigens. Why are we deifying the D-galactosamine-fucose molecules on the red cell surfaces that determine ABO Type?

Response


Dr. Klaper  might so well to check his facts before he formulates his opinions.  Lectins are not found on the surface of many foods. They are an integral component of the foods, principally found in grains, seeds and vegetable. The carbohydrates they attach to (including the blood type antigens) are on the surface of the cells of the body.

The ricin tale were first described by DJ Freed MD, Head of Immunology at the University of Manchester Hospital in Great Britain, in the introduction to his chapter on lectins in Challcombe and Brostoff's textbook Food Allergy and Intolerance, and in his review article for the journal Lancet. It is common knowledge in the scientific community. 

Dr. Klaper accuses Dr. D'Adamo of scaring people with 'lectin gremlins' when right on the home page of his own website we have the following:

"Every 30 seconds in this country, someone clutches their chest and has a heart attack," Klaper said. "Heart disease is the No. 1 cause of death in North America, and it's caused by atherosclerosis, which is that yellow greasy stuff. But heart disease is reversible, and that yellow greasy stuff will go away if you stop running animal fat through your body. A meat-centered diet, he said, also upsets the body's hormone levels and has been correlated to various forms of cancer."

Dr. Klaper's standards of proof are equally two-faced: He would like to see muscle biopsies on lectin-munching test subjects, presumably type O carnivores engorged on whole wheat bagels. Any compassionate scientist ould only be astounded by a  silly paragraph such as this.  Biopsies no less! Any volunteers? No research study review board would ever approve a study of this type. However, there are numerous studies on MEDLINE which document the sytemic effects of dietary lectins.
 
Dr. Klaper accuses Dr. D'Adamo of 'deifying' the ABO blood groups over the others. This is quite true, and there are numerous scientific reasons behind it.  For one thing, the other systems don't manifest in the digestive tract, nor appear to genetically influence the production of digestive secretions. Only ABO is expressed outside the bloodstream, and in fact is quantitatively expressed in greater amounts in digestive mucous than on red blood cells. Here Dr. Klaper falls into the common trap of medical professionals: They are simply unaware of the broader significance of ABO blood type, as they were taught in school nothing more than its importance with regard to transfusion. 

Lansteiner discovered the blood groups in 1900, not  the 1920's.



Notes
  • Did not contact Dr. D'Adamo prior to article

 

5.



Title Eat Right 4 Your Type Hype
Link
Article (HTML)
Authors
Sally Eauclaire Osborne  (Santa Fe, NM)
Distribution
The Weston Price Website, and a few low-carb diet websites
Author Qualifications
Sally Eauclaire Osborne, MS, is currently completing requirements for the CCN (Certified Clinical Nutritionist) credential with the International and American Association of Clinical Nutritionists (IAACN).  She has not authored any peer-reviewed scientific papers on blood groups, nutrition or lectins. 
Criticism Type
Opposing diet theory (paleolithic; low carb)
Article Synopsis


When we take a careful look at this theory it appears a bit "sticky." The majority of scientific studies linking blood types and lectins have involved lectins added to blood isolated in test tubes.  But foods are NOT supposed to be injected directly into the blood stream. Mother Nature designed the digestive system to process them for safe transport through the bloodstream and for easy assimilation into our cells.

A healthy body with full digestive and assimilative capabilities is completely capable of handling food lectins. In fact, this is borne out by numerous studies which suggest that lectins are either dismantled by enzymes -- which are abundantly present in raw and fermented foods - or by cooking, which destroys the helpful enzymes but compensates by denaturing complex proteins so that they can more easily be broken down during the rest of the digestive process.

Few people today, however, can boast fully functioning digestive systems. Two health problems that have undoubtedly contributed to the ability of food lectins to slip uninvited into the bloodstream are: widespread hydrochloric acid (HCl) and trypsin deficiencies, which make it difficult for people to properly digest protein, and "leaky gut" syndrome, a condition in which large undigested or partially digested protein molecules "leak" out of the GI tract and into the bloodstream, where they do not belong and where they are likely to provoke an immune system response.

Adelle Davis did not make a link between HCl deficiencies and blood type; and Dr. Atkins does not consider blood type when he tailors programs to his clients, according to Joel Pescatore, Ph.D., a nutritional counselor at the Atkins Center. So it is possible that most of the people with this problem are all Type As or ABs, the types Dr. D’Adamo feels are predisposed to chronic shortfalls of HCl. The people with ample HCl may all be Type Os, as Dr. D’Adamo claims. Yet the identification of age-related deficiencies coupled with reports of failing health suggest a gradual decline of HCl over time. If so, HCl deficiency is a preventable and correctable problem, regardless of blood type.

The obvious conclusion is that proper soaking and cooking, and the use of gelatin, can make the blood-type diets irrelevant. Type Os find they can eat grains. Type A people -- whom Dr. D’Adamo believes are natural vegetarians because they typically lack the abundant secretions of HCl necessary for easy digestion of meats -- find meats easier to digest if they are served with a gelatin-based gravy, stewed in their own broth or served along with a cup of soup. And gelatin can alleviate the allergic reactions and sensitivities that numerous research studies have connected to blood Types B and AB. Follow these simple, old-fashioned rules and those pesky lectins will be dismantled in your healthy gut and never cause problems in the bloodstream.

Response


In general Ms. Osborne seems quite new to most of the lectin material presented in the book, a fact that unfortunately  does not inhibit her from writing about them. But don't take our word for it.


Interestingly, a  quick trip to the anti-soy website that Ms. Osbourne writes for brings up the interesting observation that one should not consume soy because of its dangerous hemagglutinating lectins.  Now, it seems that when Dr. D'Adamo writes about lectins, Ms Osbourne states that they can't get in to the body.  However when they can be used to support her assertion that soy is a bad food for everyone, they apparently can enter the body and do all sorts of harm.

Right after this advice, there follows a bizarre recommendation to use gelatin in your food to block the effect of 'those pesky lectins'. In addition to the fact that many people can not use gelatin for religious reasons, in over 6 years of research  we have never seen a single study to support this contention. In fact many animal proteins, such as albumin, enhance the reactivity of lectins.

This is a completely  unsupportable  statement, with no basis in either basic immunology or molecular biology. We only feel bad for those who read it and think it is rational enough to employ.

After this paragraph, there follows a long section of her review which tries to explain why the blood type diet works, although in the beginning of her article Ms. Osbourne claims she is one of several nutritionists who see "little or nothing that clinically or scientifically supports the theory." Again, there follows a long section of dietary advice with no particular relevancy to blood type at all.

The section talking about Adelle Davis and Robert Atkins makes even less sense. Adelle Davis did not research blood groups. The head nurse at the Atkins Center has in the past gone on record stating that they did have extract problems getting the diet to work with blood type A individuals.


Notes
  • Did not contact Dr. D'Adamo prior to article

 

6.



Title Quackwatch: Non-recommended Books

Link
Article (HTML)
Authors
Barrett, Stephen MD, Edward R. Blonz, Ph.D
Distribution
Quackwatch is extensively linked throughout the internet
Author Qualifications
Stephen Barrett is a retired American psychiatrist, author, co-founder of the National Council Against Health Fraud (NCAHF), and the webmaster of Quackwatch.  Edward Blonz earned his M.S. and Ph.D. in nutrition from the University of California at Davis.
Criticism Type
Anti-alternative medicine; anti-naturopathic medicine
Article Synopsis

The Quackwatch list of non-recommended books includes Eat Right For Your Type and contains a link to a critical review written Edward Blonz.


"It may well turn out that there are important interactions with between certain foods and one's blood type. D'Adamo, unfortunately, offers little in the way of scientific evidence, relying instead on a collection of anecdotal reports and case histories. His speculation that the one gene responsible the ABO blood type could exert such a dominant influence over everything else is unable to stand on its own merits. In the end, D'Adamo adds the caveat that individual variations still occur within blood types, so you shouldn't expect all of his recommendations to apply to you. It's nice to have it both ways, especially where book sales are involved."

Response


Quackwatch is a private organization which is opposed to the study or support of any forms of alternative or naturopathic medicine, including the Office of Alternative Medicine at the National Institutes of Health (NIH).  Thus it would appear unlikely to provide for any level of fair-mindedness.

Some other authors of non-recommended books include:
  • The Editors of Time-Life Books
  • Ralph W Moss
  • Robert C Atkins, MD
  • Barry Sears
  • Larry Dossey, MD
  • John Robbins
  • Andrew Weil, MD
  • Joseph Pizzorno, ND
  • Deepak Chopra, MD
  • Herbert Benson, MD
Dr. D'Adamo has commented in the past that "the only thing worse than being included in the non-recommended reading list of Quackwatch would be to have been left out."
  
Dr. Blonz's review doesn't really provide any tangible criticism. Indeed, the first two-thirds of the article appear to be more of a recitation of the reasons why blood type would appear to influence diet.

The review contains much erroneous information, including getting the number of genes in a human being wrong (humans have about 24,000 genes, not 150,000). Dr. D'Adamo's caveat about variations was in regard to the added significance of secretor status, not some remark about "individual variations and having things both ways." Dr. Blonz appears unaware of the nontransfusion significance of blood groups: ABO genes influence the a diverse number of body functions, from blood thickness, to platelet function, to the constituents of the digestive tract lining and much more.  Perhaps if he were, he might have written a better review.


Notes
  • Did not contact Dr. D'Adamo prior to article

 

 






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