There has been a popular notion, promoted by books on the topic, that you should tailor your diet to your blood type. On face value it’s not a bad idea because our blood types are decided by our genes and these same genes are also known in some cases to be associated with an increased risk of heart disease or some cancers.
But there’s more
The jump that’s been made is that also embedded in your genetic profile based on your blood group, is the need for specific, targeted diets.
A bit of background first…..
Your blood type is decided by what molecular signals, called antigens, you have on your red blood cells. There are a large number of these red cell antigens but what most of us know about is the ABO system. If you carry the A antigen then your blood type is A, if you carry the B antigen then your blood type is B. If both then AB and if none then you’re an O.
Non-O blood types (A, B or AB) may have higher risks of heart disease than blood type O – which if true, could have something to do with how clottable the blood is. Blood type A may also have a higher risk of cancer compared to the O type.
There’s also an overlap between your blood type and your ethnicity which complicates an already complicated story.
Does that translate to diets?
There have now been several studies investigating health outcomes compared to people on blood type diets. The results are that when you look at people on blood type diets, they seem to be healthier overall, but when you dig deeper into who has benefited and in what way, there’s no relationship with an individual’s blood type.
Some people argue that they’re type O and love meat. But that’s different from saying blood type O people should be on a meat diet. Food preferences are largely genetic, from coffee to garlic to spices to meat – and not related to health outcomes. It’s possible that the genes for blood types are also linked to genes for food preferences.
Bottom line?
There are lots of reasons to change your diet to a healthier one but tailoring it to your blood type is probably a wasted effort.
References
Zhang BL, He N, Huang YB, Song FJ, Chen KX. ABO blood groups and risk of cancer: a systematic review and meta-analysis. Asian Pac J Cancer Prev. 2014;15(11):4643-50. doi: 10.7314/apjcp.2014.15.11.4643. PMID: 24969898.
Groot HE, Villegas Sierra LE, Said MA, Lipsic E, Karper JC, van der Harst P. Genetically Determined ABO Blood Group and its Associations With Health and Disease. Arterioscler Thromb Vasc Biol. 2020 Mar;40(3):830-838. doi: 10.1161/ATVBAHA.119.313658. Epub 2020 Jan 23. PMID: 31969017.
Larson NB, Decker PA, Wassel CL, Pankow JS, Tang W, Hanson NQ, Tsai MY, Bielinski SJ. Blood group antigen loci demonstrate multivariate genetic associations with circulating cellular adhesion protein levels in the Multi-Ethnic Study of Atherosclerosis. Hum Genet. 2016 Apr;135(4):415-423. doi: 10.1007/s00439-016-1643-0. Epub 2016 Feb 16. PMID: 26883866; PMCID: PMC4795966.
Cusack L, De Buck E, Compernolle V, Vandekerckhove P. Blood type diets lack supporting evidence: a systematic review. Am J Clin Nutr. 2013 Jul;98(1):99-104. doi: 10.3945/ajcn.113.058693. Epub 2013 May 22. PMID: 23697707.
Wang J, García-Bailo B, Nielsen DE, El-Sohemy A. ABO genotype, ‘blood-type’ diet and cardiometabolic risk factors. PLoS One. 2014 Jan 15;9(1):e84749. doi: 10.1371/journal.pone.0084749. PMID: 24454746; PMCID: PMC3893150.
Barnard ND, Rembert E, Freeman A, Bradshaw M, Holubkov R, Kahleova H. Blood Type Is Not Associated with Changes in Cardiometabolic Outcomes in Response to a Plant-Based Dietary Intervention. J Acad Nutr Diet. 2021 Jun;121(6):1080-1086. doi: 10.1016/j.jand.2020.08.079. Epub 2020 Dec 4. PMID: 33288495.
