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The Blood Type Diet: What’s the Deal?
The diet based on the ABO blood group system has been around for over 20 years, and popularity has not decreased. This diet advises people to eat according to their ABO blood type, claiming to
improve health and decrease risk of chronic disease such as cardiovascular disease and hypertension, among others.
A naturopathic physician, Dr. Peter D’Adamo, developed the Blood Type Diet in 1996. His book on the subject was widely popular, but lacks significant evidence to support its claims of effectiveness. Furthermore, there are few studies that even research the association between the diet and chronic disease risk.
According to D’Adamo, those with the following blood types should follow these dietary recommendations:
Type O: The hunter – has better overall health when eating a lean protein diet (meat, fish, poultry, certain fruits and vegetables) with less dairy, legumes, and grains; D’Adamo believes gluten is a leading cause for weight gain in this blood type.
Type A: The cultivator – has a more sensitive immune system and has an increased risk of developing heart disease, cancer, and diabetes. These people should consume a fresh organic vegetarian diet.
Type B: The nomad - has a strong immune system as well as a tolerant digestive system and survive chronic diseases better than other blood types. These people should consume both plants and meats (except chicken and pork), and can also have some dairy. However, they should avoid wheat, corn, lentils, tomatoes, and a few other foods.
Type AB: The enigma- the newest blood type in terms of evolution and the most complex. Seafood, tofu, dairy, beans, and grains are a large part of the recommended diet for this group. They should avoid corn, beef, chicken, and kidney beans.
This sounds like healthy eating, right? True. There are many aspects of these ways of eating that have significant nutrition improvements compared to the average Western Diet high in processed foods, added sugars, and unhealthy fats. But that doesn't mean that there is any truth behind the idea that your blood type affects your body's interactions with foods.
What about Lectins?
The idea behind the Blood Type Diet is to limit lectins, proteins that bind to sugar molecules, based on your blood type. This is derived from the idea that lectins can negatively impact some blood types more than others. However, research indicates that lectins have similar interactions with all blood types - both negative interactions, as well as positive - and do not impact one blood type over another.
The American Society of Clinical Nutrition performed a review of all the available literature on the Blood Type Diet in 2013. In this review, references were found and vetted using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Over 1400
references were found with only 1 reference being vetted that studied the relationship between the MNS antigen types and low-fat diets. However, this study did not effectively conclude any association. There was no evidence found to suggest any benefit or claim associated with the Blood Type Diet.
In 2014, another study looked into the association between the Blood Type Diet and cardiometabolic risk factors such as weight, blood pressure, blood cholesterol levels, and insulin levels. The study found that any favorable effects on these risk factors were associated with changes in dietary habits, not with the participant’s corresponding blood type. That is, when participants consumed more whole foods, especially fruits and vegetables, these risk factors declined compared to their normal dietary patterns.
So, going on a diet associated with your blood type will likely not benefit you in any specific way. However, one clear take away from this diet plan is that consuming more lean protein (such as tofu, fish, lentils, poultry, etc.), fruits, and vegetables has benefits. Different diets work for different people, and individual results vary.
It is likely people have tried the Blood Type Diet and achieved their desired results. Whether this was because of their specific blood type or just a positive change in dietary habits is another story.
Like any diet fad, there is good and bad to eating according to blood type. If it changes the way you eat for the better – perfect. If you have achieved desired results – carry on and enjoy the more nutritious lifestyle you are embarking on. If you just want to know how to eat nutritiously – consider speaking with a dietitian, eating more fruits and vegetables, and adopting a physical activity
regimen. There is a plethora of science to support that.
1. Cusack L, De Buck E, Compernolle V, et al. Blood type diets lack supporting evidence: a
systematic review. Journal of American Society for Clinical Nutrition. 2013;98:99-104.
2. Wang J, Garcia-Bailo B, Neilsen D, et al. ABO Genotype, ‘Blood Type’ Diet and Cardiometabolic Risk Factors. PLoS. 2014;9:e84749.