Conventional medical professionals do not believe that there is a relationship between blood type and food metabolism. Peter D'Adamo, a naturopathic physician, asserts that proteins associated with your blood type affect food digestion and metabolism. Although D'Adamo presents anecdotal evidence to support his claims, no scientific research corroborates these findings.
Claims
Each blood type has a specific set of molecules called glycoproteins that are displayed on red blood cells. D'Adamo believes that lectins, a type of protein found in all foods, negatively interact with specific blood types, causing blood agglutination. Avoiding foods that contain specific lectins that interact with your blood type supposedly helps you lose weight and prevent chronic disease. D'Adamo developed a blood type diet that reflects his claims about lectins, blood type and food metabolism.
Basic Research
Scientific evidence shows that some lectins do bind to blood cell glycoproteins, causing agglutination. However, no research suggests that these lectins are blood-type specific. Thus, lectins may bind to blood cells and cause agglutination, but they do not discriminate between type O, A, B or AB blood. D'Adamo has a database of lectins and the blood types with which they react. However, this information has not been corroborated by other researchers or published in a peer-reviewed journal.
Clinical Trials
A clinical trial of the blood type diet could determine whether eating a specific list of foods based on blood type would prevent harmful lectin-blood cell interactions. No clinical trials have been performed to test the blood type diet. D'Adamo conducted an informal Internet-based survey that showed that his blood type diet improves the overall health of practitioners, implying that blood type-specific lectins affect food metabolism. However, these survey results are anecdotal evidence that remains unsupported by scientific research.
Considerations
Most lectins found in food cause agglutination in people of all blood types or in no blood types. Even foods containing agglutinizing lectins, such as tomatoes or soybeans, can be digested by your body. There is no evidence to suggest that lectins negatively affect your ability to digest certain foods. Overall, no scientific research indicates that there is a relationship between blood type and food metabolism.
