The Links between Your Blood Type and Your Personality, Diet and More Explained

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The Japanese have been studying the link between blood type and personality for over 60 years. To find out more about blood types, including what foods to eat and avoid and ideal exercise, be sure to read The Body Ecology Diet.

Could blood type provide a key to wellness and even affect our personality? Canadian naturopathic doctor James D’Adamo and his son Peter D’Adamo think so. In Japan, extensive research on blood type and personality began more than 60 years ago. Blood type can be a valuable clue for understanding your own uniqueness.

Today, it is even more common to hear the Japanese ask your blood type than it is for Americans to ask your astrological sign.

To most Japanese, both biology and genetics have a role in determining personality. Approximately 90% know their blood type and for decades, blood typing has been used by employers when assessing job candidates, dating services for potential love matches and even companies for marketing soft drinks and other products.

I seem to have a special relationship with Japan. I lived there from the ages of 12 to 15. I also studied with Lima Ohsawa, who founded Macrobiotics with her husband, George Ohsawa.

During my years of travel and study in Japan, I had an opportunity to learn first-hand the ways that the Japanese used blood types and it immediately caught my attention — especially because several years earlier I had also become fascinated with the work of Dr. James D’Adamo.

His theory focused on how blood type could indicate the foods and lifestyle choices most compatible for you. One man’s food is another man’s poison. After meeting Dr. James D’Adamo and reading his book, I began to question everyone about their blood type in an attempt to verify if blood type diet indeed provided clues to our individual uniqueness.

All of these years later, I am certain it does have merit and is worth our attention. In fact, when I began working with children with autism, I quickly saw that 8 out of 10 of them are blood type “A”. An “A” myself, this told me a lot about the little bodies they were in and what their special needs were.

Knowing that blood is the most fundamental nourishment for our bodies, it seems to me that different blood types would react differently to certain substances in food. Please reflect on this theory yourself and see if you don’t agree. While there is not a lot of “hard science” to date on blood type, it makes a lot of “common sense” to look further into this theory. Blood carries the nutrients of foods into our cells and clearly not all blood is exactly the same.

While Dr. James D’Adamo’s theories were based on patient observation, his son Peter D’Adamo has tried to use a more scientific approach on the activity of lectins (proteins found in food). Peter found that eating the wrong lectins for your blood type could cause weight gain, early aging and immune problems.

I credit much of the blood type information presented in The Body Ecology Diet to both James D’Adamo and Pete D’Adamo’s research, but because of my own observations with blood type and my fortunate exposure to the Japanese theory on personality and blood type – and as you will see in more detail in The Body Ecology Diet book – I do not always agree with these two brilliant and creative men.

Blood Type and Personality

There are four blood types: O, A, AB and B, with blood type A being the most common where so much research on blood types have been focused – in Japan. In fact, 74% of the Japanese are blood type A. I find it interesting that the Japanese diet very much favors those with blood type A.

“B” type, the second most common blood type, does not do well on soy, or soba (buckwheat) common foods eaten in Japan. Fish is an important protein for B’s and the Japanese consume more fish that any country in the world. Lamb, an important protein for B’s, is not available there.

Here are some examples of blood type and personality, based on James and Peter D’Adamo’s work:

Blood Type A – Tend to be cooperative, sensitive, clever, passionate and smart. Often bottling up anxiety in order to get along with others, they may hold in their emotions until they explode. Many are tense, impatient and unable to sleep well. While they are capable of leadership positions, they may not take them because the stress is not good for their tightly wired systems. In Japan, many “A”‘s are in research. They have roles in discovering more about and refining science, economics, manufacturing, etc. Their research on microflora and other areas of medicine is some of the best and most meticulous in the world. They are perfectionists to say the least. This quality shows up in their perfecting electronics like TV’s and also less expensive more efficient cars that were originally created here in the US.

Blood type A’s tend to have more sensitive constitutions. Too much stress weakens their immunity more quickly than other blood types. Low stomach acid is common among blood type A’s even from birth, so special care should be taken when eating animal proteins. Using digestive enzymes, like Assist Dairy and Protein, along with consuming fermented foods and drinks is really a must for A’s. It is not surprising to me that fermented foods like Miso and Natto play an important role in providing easily digested protein in the Japanese Diet. They also eat raw fish which is much easier to digest than cooked.

Blood Type B – Blood type B individuals tend to be balanced – thoughtful like A’s and yet ambitious like O’s. They are empathetic, easily understanding others’ points of view, yet often hesitating to challenge or confront. Chameleon-like and flexible, they make good friends.

Peter D’Adamo found that while their immunity is strong, they are more prone to slow-growing viral infections like lupus, MS and chronic fatigue.

They may also have problems with hypoglycemia and blood sugar, especially if they eat the wrong foods.

Blood Type AB – Tend to be very charming and popular. They don’t sweat the small stuff and can be seen as spiritual and even at times a bit “flaky”. Only about 2 – 5% of the population are blood type AB. There is never a dull moment in a AB’s life, so if you find one for a friend, consider yourself lucky! Like blood type A’s, AB’s react to stress poorly. They are stronger and more active than type A’s, but need to pay attention to stress levels so that they don’t compromise their immunity. Sometimes it is difficult to be an AB. AB’s don’t like to fit in anyone else’s “boxes”. If they feel too confined, they’ll break out of that box and do things their own way. When it comes to food choices, an AB must discover when they are more B-like or A-like. For example, dairy foods like milk kefir can be excellent for them or not good at all.

– Tend to be very charming and popular. They don’t sweat the small stuff and can be seen as spiritual and even at times a bit “flaky”. Only about 2 – 5% of the population are blood type AB. There is never a dull moment in a AB’s life, so if you find one for a friend, consider yourself lucky! Like blood type A’s, AB’s react to stress poorly. They are stronger and more active than type A’s, but need to pay attention to stress levels so that they don’t compromise their immunity. Sometimes it is difficult to be an AB. AB’s don’t like to fit in anyone else’s “boxes”. If they feel too confined, they’ll break out of that box and do things their own way. When it comes to food choices, an AB must discover when they are more B-like or A-like. For example, dairy foods like milk kefir can be excellent for them or not good at all. Blood Type O – Tend to be loners or leaders and are intuitive, focused, self-reliant and daring. They handle stress better than other blood types and have strong immune systems, a well developed physique and a physically active nature. Blood type O’s tend to have sluggish blood flow and feel better with vigorous exercise for about an hour each day.

Obviously many other factors influence your personality. I think you will find like me that these blood type theories are quite fascinating. Do your own subjective research and see if you agree or disagree.

To find out more about blood types, including what foods to eat and avoid and ideal exercise, be sure to check out our 10-Day Gut Smart Challenge which hones in on finding a personalized solution for any health challenge.

In 1994, I began writing about blood type and diet in the 1st edition of The Body Ecology Diet. When Peter D’Adamo’s book, Eat Right For Your Type came out in 1996, we began to get questions on some of the conflicting information in the two books.

Based on our years of working with clients to create a system of health and healing, I feel that the Body Ecology system expands upon Peter’s work and goes further toward helping you know and care for your body.

Experiment and Be Your Own Guide

While Body Ecology believes that the blood type theory can provide clues to your diet and health, currently, there are no studies that support or deny the theory. The Body Ecology Diet offers a series of guidelines about your blood type so that you can safely experiment. Hopefully you know your blood type – if not its worth finding out (via your doctor, for example).

Keeping in mind the Body Ecology Principle of Uniqueness, blood type may be a way to modify Body Ecology guidelines for your own unique situation.

Try it out for yourself and see what you think! We’d love to hear about your experiences.