In this article, Peter D’Adamo, the creator of the blood type diet, responds to Dr. Andrew Weil’s assertions that no clear association exists between lectins and blood type.
Dr. Peter D'Adamo / Response to Various Critics
| Title | Dr. Debunker: Does the blood type diet really work? |
| Link | https://www.aarpmagazine.org/health/dr_debunker_blood_type_diet.html |
| Authors | Weil, Andrew, MD (Tucson, USA) |
| Distribution | AARP Website, AARP Magazine (Sept-Oct 2008) |
| Author Qualification | 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.' His opinion piece is shot-full of logical fallacies, including the fallacy of one-sidedness and the argument from incredulity (sometimes called "argument from ignorance"). 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 Glycotechnology; 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] Dr. Weil may wish to consult the work of William Boyd, who first wrote of the blood type specificity of lectins more than a half century 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] William Boyd's 1945 work book has been preserved clearly showing blood type specificity of lectins he researched. |
| Notes |
- Did not contact Dr. D'Adamo prior to article |
