I have recently seen a wee bit of a resurgence of people asking questions, and generally talking about eating a specific way due to their blood type, so I wanted to address the scientific soundness of the ‘Blood Type Diet’.
Disclaimer: I am an O-Positive, or a “hunter”. Ironically this should mean that I survive pretty much off meats and some vegetables, and my body doesn’t ‘do well’ on grains, legumes, or pulses. My diet consists of literally NO animal products, and a shit load of grains and legumes. According to this diet, I should be a combination of dead, limp, and lethargic. But oh well, moving on…
The largest proponent of the Blood Type Diet is “Dr.” Peter D’adamo. The only reason I have put quotations around his Doctorate title, is because he holds a PhD in Naturopathy. Regardless of your views on the effectiveness of Naturopathy, he is not somebody who has significant background into human nutrition or biochemistry, and is not someone to be looked at for any reference on the ideal way to nutrient your body.
So; The Blood Type Diet claims that certain proteins (called antigens) on the surface of red blood cells, indicate a persons dietary needs. It claims people with O, B and AB blood types must eat animal meat, and avoid many other foods in order to be healthy. It also claims that eating outside of this diet will result in lectins (carbohydrate binding proteins), therefore causing red blood cell agglutination (“clumping”) and increased incidence of pretty much all diseases..
Since the first Blood Type Diet ‘bible’ – Eat Right 4 Your Type was released in 1996, thousands of scientists have tried to substantiate this claim with population analyses of thousands of people across a huge range of ethnicities, and literally no one has found any evidence of clumping, or increased disease prevalence in people not following the Blood Type Diet (1, 2). There is also a considerable lack (as in, like, ZERO) of genuine clinical trials testing the diet in a laboratory setting, despite multiple claims by D’Adamo. His own trial, which has apparently lasted over 10 years now, has still not been published. Where is it bruh.
The Diet claims that type O (me), is the ‘hunter’, and it is suggested that they eat heavy amounts of all meats, especially red meat, in order to prevent Red Blood Cell clumping and evidential disease and probs some death too. Interestingly enough the blood type O is found in highest prevalence across all ethnicities (does that mean I’m just a commoner?). Many countries show a vegetarian and vegan population of 8-10%,or higher. So it would be expected that subsequent statistics show increased Red Blood Cell clumping and incidence of diseases in vegan and vegetarian populations. But nah, my blood is actually pretty legit ay.
However studies show vegetarian and vegan diets lead to a decreased disease incidence (no shit, well, actually lots of really good quality shit), and increased health and life expectancy (3,4,5).
It can be concluded that the diet in and of itself literally has no effect on health, disease, or longevity. In fact, because basically all recent/good/not-funded-by-animal-agriculture-companies studies are showing vegetarians and vegans experience superior health benefits, and majority of the population if they were to follow the Blood Type Diet is recommended to eat quite a bit of meat and other animal products in the diet, the Blood Type Diet can therefore be largely associated with increased onset of diseases, and decreased health and life expectancy, in comparison to a vegan diet. Big lol.
Some points to consider:
All 40,000+ species of vertebrates have red blood cells with various proteins on the cell surface. It is ridiculously unlikely that humans are the only species out of 40,000 whose dietary needs (of which evolved over hundreds of thousands of years) are suddenly associated with proteins on Red Blood Cells. Hmm..
People who change their diet to subscribe to the Blood Type Diet are typically focused on improving their health. Any beneficial results found on this diet is simply not due to the ‘theory’ of the diet, but because the diet removes a lot of processed food (probably the only good thing with this diet, and many other similar diets (cough, Paleo, cough), and the person is more likely to make healthier dietary choices because of this. Just do that anyway tho you silly goose.
Also, while it is certainly true that genetics play a role in what people can effectively digest (gluten tho), and that blood type is also dependent on genetics, correlating the two is as silly as linking squat strength to finger circumference (not that finger..)
So if you are somebody who is looking into the Blood Type Diet for the first time, please look no further. By far, the healthiest diet supported by science, is a plant-based one. (3,45)
1. Wang J, García-Bailo B, Nielsen DE, El-Sohemy A, 2014. ‘ABO genotype, ‘blood-type’ diet and cardiometabolic risk factors. PLoS ONE; 9 (1): <http://journals.plos.org/plosone/article…>
2. Cusack L, De Bruck E, Compernolle V, Vandekerckhove P. ‘Blood type diet lacks supporting evidence: a systemic review’, Am J Clin Nutr, 2013; 98 (1): <https://www.ncbi.nlm.nih.gov/pubmed/23697707>
3. Springmann M, Charles H, Godfray J, Rayner M, Scarborough P, 2016. ‘Analysis and valuation of the health and climate change cobenefits of dietary change’, PNAS; 113 (15): <http://www.pnas.org/content/113/15/4146>
4. Song M, Fung TT, Hu FB, Willett WC, Longo VD, Chan AT, Giovannucci EL, 2016. ‘Association of animal and plant protein intake with all-cause and cause-specific mortality’, JAMA Intern Med; 176 (10): <https://www.ncbi.nlm.nih.gov/pubmed/27479196>
5. Satija A, Hu FB, 2018. ‘Plant-based diets and cardiovascular health’, Trends Cardiovasc Med; DOI: <https://doi.org/10.1016/j.tcm.2018.02.004>