Blood Type Diet Basics

In recent weeks, we have discussed how essential oils are delivered throughout the body via blood flow and how emotions are simply the movement of blood flow from one part of the brain to another as you respond to circumstances or events that you didn’t expect or can’t accept.  By now you are starting to see that emotions can be affected by external influences. Today we’ll move to a third important influencer: food. This time, your blood type is involved.

The relationship between a person’s blood type and food (including susceptibility to inflammation, illness, disease, and more) is not a new concept, but it is one that has not been studied widely in the scientific community. We know that there are 3 basic blood types – O, A, and B – and a fourth, relatively modern type called AB. Although there is a belief that the original blood type was A, it disappeared and was replaced by O as the common blood type of humans in very ancient times. O is still the most common blood type, though the other types have geographical and people group strongholds.

People ask me what the basis is for the Blood Type Diet food lists. The simple explanation is that all foods have lectins (specialized proteins) which are interpreted by your blood’s antigens as their same blood type or a different blood type. When a food’s lectins are interpreted as the same type as the body’s blood, that food is processed easily by your body and may even support increased microbiome diversity and optimal weight. When the food’s lectins appear to be a different blood type, the antigens treat them as foreign. The cells can agglutinate (clump together), causing sluggishness, inflammation, and eventually disease. When the bacteria in your gut are out of balance, both your body systems and your emotions are also out of balance. Just as you would not want to receive a foreign blood type in a transfusion, you probably would not want to cause problems in your own body and emotions by eating incompatible foods.

Blood Group Antigens (image from Wikipedia):

A Has only A antigen on red cells (and B antibody in the plasma)

B Has only B antigen on red cells (and A antibody in the plasma)

AB Has both A and B antigens on red cells (but neither A nor B antibody in the plasma)

O Has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)

In addition to the A and B antigens, there is a third antigen called the Rh factor, which can be either present (+) or absent ( – ). In general, Rh negative blood is given to Rh-negative patients, and Rh positive blood or Rh negative blood may be given to Rh positive patients.

The Rh factor does not seem to influence food processing. However, about 20% of persons with a certain blood type (varies by ethnicity) do not carry blood type markers in bodily fluids other than their blood (saliva, urine, etc.). These non-secretors have food lists that vary somewhat from those for secretors, and there is a simple spit test that can be administered once the blood type is known.

More recently, genotype analysis has been available to customize food lists to the individual (see below). However, the blood type and secretor status are enough for most people to experience excellent results from following general lists.

The study of the effect of foods on the human body based on blood type began with experiments by an American known as the ”Father of Naturopathy”, Dr. James L. D’Adamo, more than 50 years ago.  Eventually his work was carried on jointly with his son, Dr. Peter J. D’Adamo (named Physician of the Year in 1990 by the American Association of Naturopathic Physicians) until the elder’s death in 2013. Dr. Peter continues to research, write, and spread the word.

Type O can be broadly described as a caveman or Paleo blood type, and type O individuals retain the high levels of hydrochloric (digestive) acid that would be most helpful for eating raw meat and greens. Type A reappeared as humans began to settle down, live in fixed communities, and raise grains and smaller animals. Their digestive acid levels are very low because meat was a much less significant part of their diet. The most suitable A diet is, therefore, primarily vegetarian or even vegan. As humans moved farther away from warmer climates to the northern mountainous regions of Eastern Europe and Asia, the B blood type developed.  Bs were, by necessity, nomadic herders whose best diet was of the northern animals they could herd or catch and fermented dairy together with various greens and some grains: their digestive acid levels are elevated but less than those of type Os. The optimal B diet can be described as relatively balanced across food groups. Type AB is an eclectic mix, closest to A but thriving on specific best foods coming from each of the other 3.

As you may have guessed by now, I am not a fan of a one-size-fits-all food pyramid. For those who wonder what the recommended protein-carbohydrate-fat proportions are with the Blood Type Diet, here you go:

  • For Type O: Around 40% comes from animal protein (meat and fish); 40% from fruits, vegetables, nuts, seeds and grains; 20% fat.
  • For Type A: Around 70% comes from fruits, vegetables and grains; 21% comes from protein-rich foods such as nuts and seeds, tofu, certain dairy products and fish; around 9% comes from fat.
  • For Type B: About 54% comes from fruits, vegetables, nuts, seeds and grains; 33% comes from protein from animals, fish and dairy; and 13% comes from fat.
  • For Type AB: About 60% comes from plant-based food such as fruits, vegetables, nuts, seeds and grains; 20% comes from animal protein (fish and meat); and 20% comes from fat.

As noted above, an individual may express blood type antigens only in the blood (non-secretor) or in all bodily fluids (secretor). In late 2017, a 20th anniversary edition of “Eat Right 4 Your Type” was published. This edition included updated food lists to reflect Beneficial, Neutral, and Avoid foods specifically for the secretor population of each blood type. Non-secretors and those who know there genotype can get general information about history, exercise, and medical/supplement needs in the book. For all blood types – and especially non-secretors – two additional wonderful cyber resources are: The Blood Type Diet mobile app and an online Food Values lookup tables:

Blood Type Diet protocols continue to be refined and individualized (much like the refinements in DNA testing results for genealogy). In late 2007, Dr. Peter published “The GenoType Diet”, moving beyond simple blood type and secretor status to genotype (the measurements of various parts of your body that indicate your phenotype) and epigenetics (the ways in which members of your specific family bloodline interacted with the environment over time to heighten or suppress the “volume” of each gene: the gene doesn’t change but the ongoing experiential overlay mutes or heightens its effect). This is important when, for example, you have inherited a blood type that would normally provide protections against specific illnesses and diseases but those protections may have been reduced because of bloodline lifestyle adaptations (an ancestor who worked around lead or coal, for example). Today, SWAMI XPress web-based software combines blood type, secretor status, and body type measurements and performs 12,600 different calculations on the nutrient values of 800 different foods to determine the foods that will yield the healthiest results for each individual. If you are what you eat, you now have more control than ever to determine what that is.

I am not a medical professional, and this information is not meant as medical advice. It is simply my understanding of the basic tenets of the Blood Type Diet. I have been learning about and following the Blood Type Diet for more than 10 years and continue to find it to be the best way for me and many, many others around the globe to maintain a healthy weight, energy, overall wellness, mental clarity, and emotional wellbeing. Whether it is simply that whole foods and balanced portions are central to each type’s lists (as many in the scientific community assert) or whether this way to eat is yet another example of each body’s unique needs and responses to changing inputs and environments, you can be the judge.

If you’d like to explore this way of making food decisions, I am happy to partner with you and point you to the many resources available. If you are choosing a different way, I encourage you to stick to the principles of fresh, whole, organic foods and balance across food types.

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