Eating According To Your Blood Type Will Help Improve Your Diet & Health!

You may be wondering what your blood type has to do with what you eat! Extensive research has found that diet according to blood type is the most important key to the mysteries of personal health, disease, aging, physical vitality and strength. Blood type determines a person’s susceptibility to illness and which foods you should eat. It answers the questions of why some people have ‘allergies’ to certain foods, while other people thrive on them, and why some people rapidly lose weight on certain diets and others actually gain weight or remain the same.

Breakthroughs on the connection between blood type and diet started in the 1960’s when researchers discovered that certain diseases were associated with blood type diet danger. These diseases include peptic ulcers, stomach cancer, and pernicious anemia. The conclusion of this extensive research revealed that there is a definite link between blood type and diet. When you use your blood type as the first key for your ideal diet, you will be healthier, will easily reach your ideal weight and will slow the process of ageing. Food sensitivities and allergies now make a lot more sense. Why can some people eat tomatoes for instance but others say: “It’s not that I don’t like tomatoes, it’s that they don’t like me”? Why can some people tolerate wheat while it leaves others feeling bloated and in pain? You will find that eating according to blood type will eliminate many of the foods that cause you discomfort, without having to go for allergy tests.

Why are there different blood types?

Blood is life – our entire individual genetic map is found in a tiny drop of blood, which cannot be seen with the naked eye. As humans evolved, blood began to change. But this change took place over thousands of years. It will take humans thousands of years – if ever - to adapt to the junk food eating patterns that began in the 1950’s!

Change in climate and change in available food produced new blood types. This adaptation demonstrates the ability of the human species to acclimatize itself to different environmental challenges. A piece of bad meat could be poisonous; a cut might fester and cause a deadly infection. And yet the human race survived. The story of that survival is tied to our digestive and immune systems. It is in these two areas that most of the distinctions between blood types are found.

Dr. Peter J D’Adamo and his father, Dr. James D’Adamo pioneered blood type eating. Their scientific studies are well documented with thousands of case histories. Many therapists have managed to restore and maintain their patient’s health by using blood type eating alone. They have produced some excellent reference books and run a very helpful website, which includes food lists for all the blood types as well as extensive research and information.

The blood types in brief summary

1. Type O – most common blood type. Early man, hunter-gatherer.

2. Type A – crop growing.

3. Type B – domestication of animals.

4. Type AB – the rarest blood type. The modern intermingling of different groups.

See below for more information.

Food allergies explained

One in three people suffer from allergies at some time in their lives and food is the most common cause of allergy. The symptoms of allergy develop insidiously, so many people feel below par without realizing that they are suffering from a food allergy.

The following symptoms are all linked to food allergy:

  • Anxiety, chronic fatigue syndrome, depression

  • Sleep disorders, insomnia

  • Arthritis, asthma, bronchitis, eczema/dermatitis, hay fever, rhinitis

  • Bedwetting, learning disorders, attention deficit disorder

  • Bloating, celiac disease, colitis, Crohn’s disease, diarrhea, inflammatory bowel disease

  • Diabetes

  • Ear infections, tonsillitis

  • Headaches

  • Multiple sclerosis

  • Weight gain

Food allergies are not digestive problems. They are reactions of the immune system to certain foods. The immune system creates an antibody to fight the intrusion of this food in the system – much as it would a virus or bacteria.

The body literally does not recognize certain lectins (tiny protein particles in food – see Lectins, as food and so treats them as a foreign substance. The body then not only misses out on the nutrition that that specific food could provide, but also has to work harder to get rid of the ‘poison’. When it can no longer do this, the lectins simply accumulate in specific areas (for example, the intestines, joints, and organs).

Many people may be symptom-free for most of their lives. Some people will also not notice any immediate difference in the way they feel once eating according to their blood type. This is due to personal pain thresholds, individual sensitivity levels, levels of stress and therefore how a person’s body is coping with ‘food stresses’, blood type and how much a person is deviating from their ideal foods on their current diet, and a myriad of other factors. But there is no doubt that as you get older the effects of incorrect eating will start emerging in different ways. The effect is accumulative – years of eating the incorrect foods for your blood type can eventually lead to illnesses such as arthritis, Irritable Bowel Syndrome, liver cirrhosis or Alzheimer’s disease to name a few.

The unfortunate news for people with very sensitive systems (or those damaged through years of eating incorrectly) is that a ‘toxic’ food (for your specific blood type) entering your system has a magnified effect of up to 90 times that of someone for whom it is not toxic! The good news is that eliminating the offending foods for a period usually reduces sensitivity to a large degree, allowing for the re-introduction of the food in small quantities.

The immune system

The immune system is what keeps us well. It is the body’s own defense system against disease, infections and illness. It works by defining ‘self’ and destroying ‘non-self’. This ability is critical, for without it the immune system could attack our own tissues by mistake, or allow a dangerous organism access to vital areas of the body. In other words, the immune system recognizes ‘us’ and kills ‘them’.

Blood type is the key to our body’s immune system. Each blood type’s immune defenses work slightly differently from the others.  These defenses control the influence of viruses, bacteria, infections, chemicals, stress and an assortment of invaders and conditions, which might compromise our immune system.

Modern drugs, such as antibiotics and chemotherapy, were developed to destroy the microorganisms responsible for infection, but by their nature these drugs are poisonous to our systems. Antibiotics initially fight bacterial infections, but their prolonged use has led to deadly drug-resistant ‘super-bugs’; and chemotherapy, while attacking cancerous cells, lowers the resistance of the immune system.

In recent years attention has turned away from drugs and towards strengthening our immunity as an alternative to fighting disease. Even Louis Pasteur, the ‘discoverer’ of germs, realized late in his life that strengthening the body’s own immunity rather than killing invading germs was a far more effective wellness strategy. The immune system can rapidly produce millions of antibodies, which have the ability to fight against invading antigens. This rapid reaction by the immune system makes all the difference between a mild cold or stomach bug, to a heavy dose of the flu or a debilitating attack of food poisoning. Taken a step farther, this rapid reaction by the immune system may make the difference between a non-malignant breast lump and cancer, or symptom-free HIV and full-blown AIDS.


One of the ways in which our immune system recognizes ‘friend or foe’ in our bodies, is through chemical markers called antigens which are found on our cells. Antigens could be described as the ‘chemical fingerprint’ of our body. The antigen that determines blood type is one of the most powerful in the human body. When the immune system sizes up a potential foe (a foreign antigen from bacteria), one of the first things it checks is our blood type antigen.

Each blood type possesses a different antigen with its own specific chemical structure. The blood types are named after the blood type antigen unique to that type. Thus blood type A has A antigens, B has B, and AB has both A and B. Blood type O has the simplest structure, and has no additional antigens as do A, B and AB.

Foods have antigens (markers) that ‘look like’ A or B markers. This makes the cells judge them as friend or foe and treat them accordingly. When the food antigen marker is the same as the blood markers, it is treated as a friend and is extremely compatible with the body.

To put it another way, your body is compatible with foods that contain lectins that ‘look like’ your blood type antigen. It does not produce antibodies to these foods, and so your body easily digests and absorbs them.

Secretor status

Antigens are present in the blood and, in most individuals, in bodily fluids such as saliva. If antigens are present in your bodily fluids, you are known as a ‘secretor’. If they are not present in your bodily fluids, you are a ‘non-secretor’. This fact is important for the diet, so it is important that you find out your secretor status.

Some researchers have found a correlation between Rhesus status and Secretor status. If you are unable to determine your Secretor status, a general rule of thumb is that Rhesus + usually denotes a secretor, and Rhesus – usually denotes a non-secretor. This research has not been sufficiently documented at this stage, so if possible and if available in your country, a test for secretor status should be done at the same time as the test for your blood type.

Secretors are shown as ‘1’ and non-secretors as ‘2’, for example, A1 (secretor) or A2 (non-secretor).


Antibodies could be described as ‘smart bombs’ for our immune systems. When the blood type antigen senses that a foreign antigen has entered the system, it creates antibodies to that antigen. The function of these antibodies is to attach and tag the foreign antigen for destruction. A continual battle wages between our immune system and intruders, who are also busy trying to mutate their antigens to some new form that the body will not recognize. The immune system controls this process and is constantly developing new antibodies to respond to these mutations, as well as to new antigens entering the system. (This incidentally is where blood types for blood transfusion are so important – some blood types produce antibodies to other blood types.)

When an antibody finds a foreign antigen, it attaches itself to the antigen and makes it ‘sticky’. This makes the antigens come together in clumps, which makes the task of getting rid of them easier for the body than trying to ‘sweep up’ individual offenders. This process is called agglutination.


Lectins are minute protein particles present in most foods. The antibodies of each blood type see some types of foods (more specifically, the lectins in the food) as enemies, and agglutinate (stick together, ready for ‘sweeping up’ by the antibodies) those food cells once they enter the system – literally rejecting them as a harmful substance. Each blood type has its own lectins, which it regards as ‘the enemy’. This means that a lectin, which may be harmful to the cells of one blood type, may be beneficial to the cells of another. So the term ‘health food’ now has to be seen in the context of blood type.

For example: someone with type A blood drinks a glass of milk. The milk is digested in the stomach through the process of acid hydrolysis. However, the lectin protein does not get fully digested, so stays intact. It may interact directly with the lining of the stomach or intestines, or it may get absorbed into the blood stream and settle somewhere in the body. Once it settles, it clumps the cells in that region together as if they were foreign invaders. This clumping can cause irritable bowel syndrome, cirrhosis of the liver, or it can block the flow of blood through the kidneys – to name just a few of the effects.

Similarly, a person with blood type O eats a piece of bread. The lectins (called gluten)in the wheat are not fully digested by an O blood type. So they bind to the lining of the small intestine, causing inflammation and painful irritation as antibodies try get rid of them.

Eating for your blood type

Each human being is different and a mass approach to dieting, as many people would already have discovered, is often ineffective. The first step in determining your ideal diet is to establish your blood type and the right foods diet blood type..

The only way to do this is to have it tested by a pathologist or at a pathological laboratory. These can be found at any hospital or clinic. Alternatively a doctor can take a blood sample and send it away for typing. Many health centers offer on-the-spot blood typing.

When testing for your blood type, ask to have your ‘secretor status’ tested as well. A saliva sample is needed for this. The tests are inexpensive and results are available fairly quickly. Suitable foods for secretors or non-secretors are shown as ‘1’ for secretors, ‘2’ for non-secretors.

Change is extremely difficult for the body and mind, and in order to be successful, needs to be gradual. The trick is to start with one or two minor changes and keep changing until the body is in a state of abundant health. This, after all, is the goal – good health, vitality and freedom from illness, well into old age. An automatic result of eating for your type will be weight stabilization, especially weight loss if you are overweight – and you will not even notice it. It will not be difficult to reach or stay at your correct body weight if you follow the plan – for the rest of your life!

As you make gradual changes, the body and mind adapts, and you start losing cravings for certain foods and developing a taste for others. The taste buds begin preferring the choices that serve your body instead of harming it.

The quickest way of correcting your diet is to cut out most harmful food immediately. The easiest way to do this is to find substitutes, and eventually to start changing your actual way of eating. Make the Change! gives some good tips on how to do this. 

NOTE: If you are very ill or trying to treat a specific condition, the stricter you can be and the sooner you can do it, the better. For example, if you have just been diagnosed with arthritis and you are blood type O, immediately cut out potatoes, wheat and corn (see below), treating them as poison to your body. You cannot afford yourself the luxury either of eating the occasional serving of harmful food, as this will cause you to relapse and you will have to work mentally harder to gain the ground lost.

Automatic weight loss!

The goal of optimal health is to achieve and maintain vitality, normal weight and freedom from illness well into old age. If you are overweight, a side effect of this lifestyle will be weight loss. The reasons for this are:

  • As the body starts eliminating poorly digested or toxic foods, the first thing it does is to try flush out toxins already present. These toxins are mainly deposited in the fat tissue, so the process of eliminating toxins also means eliminating fat.

  • The lectin activity of the wrong foods often interferes with the digestive process and slows down the rate of food metabolism, so calories are not burned efficiently. Once you are eating the correct foods, the digestive system starts working more efficiently and your metabolism will speed up.

  • Eating the right foods for your blood type regulates the production of insulin, lessens strain on the system and evens out blood sugar levels. Weight retention is reduced.

  • If the hormonal balance of the body is upset, water retention and thyroid disorders can follow. Eating the correct foods helps the body recover and weight loss is an automatic consequence.