Blood Type Diet

The day I found out that the reason I loved meat so much when my beloved cringed at the mere thought of it might be down to the fact we were two different blood types, I rejoiced. A lots of my likes and dislikes suddenly made sense, too – I was never too big on lentils, grains, things made of wheat which always made me feel – pardon the sexiness of this post – very bloated. Even bulgur and other hailed new-generation vegetarian dishes didn’t do the job for me. Hubby-to-be, on the other hand, gobbles down a good pound of oat flakes in the morning at breakfast, with bread – before moving on to bulgur for lunch and, if he wins the fight, pasta (with cheddar on top!) at night. Believe me or not, HE IS NOT FAT. He is actually, annoyingly, way fitter (sigh) than I would ever be on a diet of pasta and cheese. But that’s another topic altogether…

The debate took on an almost philosophical quality (“No! MY family’s right…No! MINE is…”) when we realised that it had become about what my mother thought was a healthy diet vs. what his mother thought was a healthy diet. Of course, they didn’t agree at all. My mom is all about lean chicken and green leafy vegetables and tamarind powder – bread is the Enemy, capital E. His mother (a mean cook, it must be said) always makes sure that there is some “real food” on the table during all meals so her “little ones” won’t starve to death – and she bakes a yummy loaf of bread every night before going to bed…

So rejoice, I did, when I read about Dr D’Adamo’s ideas on the relationship between diet and health. His basic postulate is quite simple, and, although like everything on this blog, it is very debated – it speaks volumes to me. Dr D’adamo says that your blood type – O, A, B or AB – determines your body’s ability to absorb nutrients, fight off diseases, and handle stress.

Historical origins
His website says that his recommendations were born out of evolutionary history, and, specifically, “the observation that the different blood types emerged as the environmental conditions and eating styles of our ancestors changed”.

Research seems to show that between 50,000 BC and 25,000 BC, all humans shared the same blood type – the early hunters were all Type O, and thrived on a meat-based diet. As people settled and lifestyles became less nomadic, between 25,000 BC and 15,000 BC, human bodies evolved and adapted, and it seems that the Type A blood type emerged around that time. Climactic conditions and changes in the western Himalaya mountains led to the appearance of Type B a little later, and the appearance of the Type AB blood type is thought to be due to the blending of Type A and Type B in modern civilisation. Because the emergence of new blood types made it possible for our ancestors to survive the changing environmental conditions, some researchers believe that our dietary environment, blood type and health are intricately related.

Physiological principles
According to Dr D’Adamo, the physiological reason why blood type is so important relates to lectins, which are protein-like substances found in many commonly eaten foods. “The Lectins, also known as “phytohemagglutins”, were first identified in 1888, at which time it was discovered that lectins interact with sugar-containing molecules on the surface of cells. This discovery allowed certain lectins to be used in blood typing, since blood type is determined by the presence (or absence) of specific sugar-protein residues on the surface of red blood cells. These residues are called antigens. Antigens play a crucial role in the function of the immune system, as they allow your body to distinguish between what is friend and what is foe”.

Dr D’Adamo says that when an antigen enters the body that is unlike the blood type antigen, our immune system identifies it as a foreigner and prepares to attack and kill the invader; it produces antibodies which attach to the foreign antigen. This process, called agglutination, is necessary for our immune system to eradicate foreign invaders and protect us from colds, flus, and – Dr D’Adamo argues – even cancer.

The agglutinating of blood cells is not always beneficial, however. At its extreme, such clumping can cause a blockage in blood vessels, causing a stroke. “Although most of the lectins found in food are destroyed by cooking, digestive enzymes, or are inactivated within the gut, at least 5% of the lectins we take in through our diet are absorbed into the bloodstream, and some of these are incompatible with our blood type. Many food lectins look very similar to the antigen that determines one of the four blood types or else bind directly to blood type antigens. In either case, this resemblance can lead to agglutination” – and become harmful.

“Simply put, when you eat a food containing lectins that are incompatible with your blood type antigen, the lectins target an organ or bodily system (kidneys’ liver, brain, stomach, etc.) and begin to agglutinate blood cells in the area.” Dr. D’Adamo implicates lectin-caused agglutination as a significant contributing factor to many common health complaints. Some scientific evidence supports his contention; for example, the lectin component of gluten – a protein found in wheat and many other grains  – is known to interact with the mucous membranes in the gastrointestinal tract of people with celiac disease creating inflammation.

Most of the criticism that the Blood Type Diet has met with so far hinges around the lack of clinical trials to support Dr D’Adamo’s research. Again, his findings are to be taken with a grain of salt – no eating routine should ever be overhauled to religiously follow any strict rule or the latest trend in fashionable dieting. Listening to your body works, however, because at the end of the day you know better than anyone else what makes you feel well and what doesn’t; on that basis some of the guiding principles outlined below might resonate with you.

Guiding principles
Eating according to your type does not mean entirely eradicating certain food groups from your diet – I firmly believe that we are all omnivores and meant to be eating a balanced diet of all kinds of foods, unless we choose to discard certain kinds for philosophical or religious reasons. By diet, I do not mean “a way to lose weight” but a way to balance your daily food intake so it’s optimal for you; balance, as in many other things in life, is key.

Knowing your blood type and your body’s sensitivities to certain types of foods can greatly help to make you feel better over the long-term. This is something that, once you read the specifics of your type, will likely feel largely intuitive anyway. Perhaps, like me, you have already noticed that you feel weak if you go too many days without a good steak. Or perhaps, like hubby-to-be, you actually feel awful if you have red meat at night – you literally cannot stomach it.

The table below highlights the four blood types and summarises the foods which are deemed “highly beneficial”, “neutral”, or “to be avoided” by the proponents of the Blood Type Diet. Each recommendation is based on the alleged-lectin content of the food. In upcoming posts, I will review the recommendations for each blood type in more detail, including foods that promote weight gain / loss for each blood type.

Peter D’Adamo is the author of three books on the relationship between blood type, diet and disease:

  • Eat Right For Your Type
  • Cook Right For Your Type
  • Live Right For Your Type

Additional information on the Blood Type Diet can be found at Dr. D’Adamo’s web page.

Other web pages on the subject:


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s