Posted 27 January 2014
A Canadian research team has conducted a study that fails to support the “blood type diet” theories of naturopath Peter D’Adamo. The Canadian study involved 1,455 people whose dietary intake was assessed to determine how well they had adhered to each of D’Adamo’s “blood-type” diets. Some participants improved their cardiovascular risk factors, which is not surprising because some of D’Adamo’s dietary strategies coincide with standard science-based recommendations. However, the study found no relationship between the improvements and the subject’s ABO blood types, which negates D’Adamo’s basic assertions. [Wang J and others. ABO genotype, ‘blood-type’ diet and cardiometabolic risk factors. PLoS ONE 9(1): e84749, 2014]
D’Adamo claims that reactions between food lectins and our blood are responsible for many ailments and that avoiding lectin-containing foods will benefit health. He further claims that ABO blood groups reveal the dietary habits of our ancestors and that adhering to a diet specific to one’s blood group can improve health and decrease risk of chronic diseases such as cardiovascular disease. His publications list foods that supposedly are beneficial or harmful for each of four major blood types. His Web site contains hundreds of supporting anecdotes, but a 2013 review found no evidence that his dietary strategies had previously been tested. [Cusack L and others. Blood type diets lack supporting evidence: A systematic review. American Journal of Clinical Nutrition 98:99-104, 2013] D’Adamo’s first book, Eat Right 4 Your Type, originally published in 1996, has sold millions of copies and been followed by additional books and an extensive line of dietary supplements, many of which are said to be blood-type specific. The D’Adamo Personalized Nutrition 2012-2013 catalog asserts that D’Adamo is “the foremost authority on blood type in the world.” Quackwatch has a critical review of his 1996 book.
Extracted from Consumer Health Digest #14-03, January 26, 2014