Eat Right for Your Blood Type

So, how do you determine which foods contain lectins compatible with your blood type? Finally, a diet strategy exists - with serious scientific substantiation - that makes sense of the fact that individuals vary tremendously in their responses to the same diet. This approach offers us scientifically validated guidelines for choosing the foods that will promote our optimal health. The personal archives of Dr. Peter D'Adamo, clinician, researcher and author of Eat Right 4 Your Type, now include more than 3,000 scientific references, in several languages and going back 75 years, on the connections between blood types, food and disease.

The premise of Dr. D'Adamo's theory is simple: Your blood type - O, A, B or AB - is a powerful genetic fingerprint that provides the operations code for your body's digestive and immune systems. Your blood type is a key indicator of your body chemistry, how you absorb nutrients, your susceptibility to illness, and the way your body deals with stress.

Each of the four blood types contains specific and different chemical markers called antigens that signal the immune system what is friend and what is foe. When an antigen enters your body that is unlike your blood type antigen, your immune system creates an antibody to that antigen. The antibody then attaches to the foreigner, tagging it and making it chemically sticky, a process called agglutination. Agglutinated antigens on viruses, bacteria, parasites, cancerous cells, etc., attract one another, so they clump together, making it easy for your immune system to efficiently destroy them.

And - here's the connection between your blood type and your diet - proteins found in foods called lectins, if they are not compatible with your blood type antigens, agglutinate your red blood cells. Many food lectins look so much like the blood antigen of one blood type, that the antigens of the other blood types see these lectins as enemies, which starts the agglutination process.

In addition, incompatible lectins in foods resist digestion and themselves agglutinate cells in the stomach or intestinal tract, or they enter the bloodstream, travel elsewhere (e.g., kidneys, liver, brain), and agglutinate cells where they deposit. Incompatible lectins gum up body organs and systems, interfere with digestion, food metabolism, insulin production and hormonal balance.

So, how do you determine which foods contain lectins compatible with your blood type? The answer is evolutionary.

Type O - The Hunter

Type O, the oldest blood type, reflects humanity's emergence as hunter-gatherers. Still the most prevalent blood type, (44 percent of the American population), the Type O metabolic engine runs best on high-protein, low-carbohydrate fuel: small, frequent servings of meat (excluding pork), poultry and fish along with vegetables and fruit.

Food foes for Type Os include most grains (especially wheat), legumes, several vegetables in the Brassica family (cabbage, Brussels sprouts, cauliflower, mustard greens) and dairy products. Unavailable to Type Os' hunter ancestors, these foods contain lectins that cause agglutination reactions in the Type O body chemistry.

Tomatoes - which contain an especially potent lectin capable of agglutinating A, B and O blood types, and are therefore called a panhemmaglutinin - should also be avoided. Tomato lectin has also been shown to lower the concentration of mucin in the gut, to bind to nerve tissue, and to bind to, thus locking open, a cellular mechanism that induces stomach acid production.

Vigorous aerobic exercise is the best form of stress release for Type Os who, in legacy from their hunter ancestors, have fast burning metabolisms that produce lots of energy. Studies show that when stressed, Type Os tend to secrete higher levels of the neurotransmitters adrenaline and norepinephrine than the other blood types. They also have lower levels of an important enzyme called monoamine oxidase (MAO) than the other types. Vigorous aerobic exercise helps regulate and balance these stress chemicals.

Type Os who don't eat right increase their risks for:




Ulcers - geared for digesting meat, the Type O stomach produces lots of acid.

Inflammatory diseases, such as irritable bowel syndrome and arthritis - the agglutinating lectin in wheat triggers an inflammatory reaction in the Type O intestinal tract.

Obesity - lectins in wheat and corn mimic Type O insulin (when high, insulin preferentially puts sugar into fat cells).

Thyroid problems - Type Os' typically weak thyroid function can be further inhibited by lectins in cabbage, Brussels sprouts, cauliflower and mustard greens.


Type A - The Cultivator

Type A, the cultivator, was next to evolve as the vast herds began to thin, and humans were forced to settle and learn how to grow and preserve food. The Type A digestive system adapted to a diet of proteins derived primarily from plants and grains, along with fish from nearby lakes, rivers and seas.

Type A (40 percent of the American population) still thrives on a primarily vegetarian diet: soy products, beans and legumes, grains, vegetables, fruits and small portions of fish. Occasional consumption of poultry and fermented dairy products is also well tolerated.

Foods containing lectins that agglutinate Type As are those rarely encountered by their agrarian ancestors - meat and dairy products. Type As' low stomach acid, geared to digesting vegetables, is inadequate for these animal proteins.

Meat cannot be metabolized quickly, with the result that toxins are produced in the gut, inflaming the gut mucosa. Once the gut mucosa is injured, toxins and lectins can leak into general circulation and cause problems wherever they end up.

Poorly digested dairy foods provoke insulin reactions, and when insulin's job of ushering sugar into cells doesn't get done, metabolism slows, energy drops and unused calories are transferred to fat stores.

For the reasons explained under Type O, tomatoes should also be avoided.

When stressed, Type As get nervous, anxious and irritable. Studies show they have much higher levels of the adrenal hormone cortisol than the other blood types. This may explain why this blood type has a higher incidence of heart disease than the other types. The risk of getting heart disease by virtue of being blood type A is only slightly lower than the increased risk associated with elevated cholesterol, and even higher than that associated with high homocysteine levels.

Heavy, competitive sports exhaust Type As' nervous energy. They do best with quieting, calming techniques, such as yoga, tai chi or meditation that ease tension, or non-confrontational, relaxing exercises like golf, hiking, low impact aerobics, swimming or bicycling.

Type As are prone to:




Cardiovascular disease - poor digestion of meat and saturated fats results in high circulating levels of triglycerides and cholesterol.

Cancer - the antigens on many tumor cells, especially breast cancer cells, are A-like, so are not recognized as foes by the Type A immune system.

Pernicious anemia - Type As, with their low stomach acid, have the most difficulty absorbing B12 (cobalamin), a necessary factor for the production of hemoglobin.
Type B - The Nomad

A balanced adaptation to life in high altitudes, nomadic existence and dairy herding, Type B (9 percent of the American population), was next on the scene. Type Bs do best on a varied diet including game meat (rabbit, venison), herd meat (lamb, mutton), eggs, low-fat dairy products, fish, some beans and legumes (kidney, lima, navy, red soy), some grains (millet, oats, rice, spelt), plus fruits and vegetables.

Foods that cause problems for Type B include:




Corn, buckwheat, lentils, peanuts, sesame seeds and wheat - all of which contain lectins that slow Type B metabolism, resulting in fatigue, fluid retention and hypoglycemia.

Chicken - which contains an agglutinating lectin that attacks the Type B bloodstream - can lead to strokes and immune disorders.

Some beans - lentils, garbanzos, pintos and black-eyed peas - whose lectins interfere with insulin production.

As explained under Type O, tomatoes agglutinate Types A, B and O, so they should also be avoided.
Less confrontational than Type Os, but more physically charged than Type As, balanced Type Bs need a mix of intense physical activity along with some relaxing forms of exercise - for example, three days a week of aerobics, tennis, martial arts, hiking, cycling, swimming, jogging or weight lifting, plus two days a week of golf, tai chi or yoga.

Type Bs are at higher risk to slow-growing viruses that attack the nervous system, eventually producing diseases such as MS and Lou Gehrig's disease. These viruses, which have a B-like appearance, are particularly dangerous for Type Bs whose immune systems don't see them as enemies. Chicken and corn, whose lectins may render Type Bs even more susceptible to these viruses, should be avoided.

Type AB - The Enigma

The new blood on the block, just 10 to 15 centuries old, Type AB is still very rare - somewhere between two percent and five percent of the American population - and may still be evolving, in response to what, we're not yet sure. We do know that Type AB combines most of the strengths and weaknesses of both Type A and Type B.

If you are Type AB, your optimal diet is basically Type A fish and vegetarian fare with some cultured dairy products and lots of idiosyncratic food foes. You'll need to review the Eat Right 4 Your Type food lists and monitor your diet more than the other types.

Type ABs have inherited Type As' low stomach acid along with Type Bs' adaptation to meat. The result is that small servings of Type B meats are good (lamb, mutton, rabbit, turkey), but beef is too hard to digest, so it is stored as fat, and chicken irritates Type AB blood and digestive tracts. Tofu and seafood (Type A), fermented dairy products and eggs (Type B), are also well metabolized protein sources for Type AB.

Foods that pose problems for Type ABs are a mixture of those foods Types A and B should avoid. Type B inheritance shows up in a negative reaction to kidney or lima beans, corn, buckwheat and sesame seeds, while Type A propensities make lentils, soy and peanuts good choices, but not lima, garbanzo or kidney beans.

Type ABs are also more A-like in being able to tolerate wheat gluten, although wheat does tend to slow AB metabolism, leading to weight gain.

In a class by itself, Type AB is the only blood type seemingly immune to tomatoes, perhaps because the A and B antibodies seem to inhibit each other from binding to tomato lectin.

Type ABs have inherited the stress-pattern of Type As and react to the first stage of stress - the alarm stage - intellectually. Unregulated adrenal glands produce anxiety, irritability and hyperactivity, tiring out Type ABs and rendering them more susceptible to infections and unfriendly bacteria.

Beneficial exercises for Type AB are those that provide calm and focus such as tai chi, hatha yoga and akido. Other Type A exercises beneficial for Type AB include golf, hiking, swimming, bicycling and low-impact aerobics.

Most Type AB disease susceptibilities are A-like. Type ABs are susceptible to infections, heart disease and various forms of cancer. Like Type A's, Type ABs, with their low stomach acid, have a tendency toward pernicious anemia. They are also at risk for B-like viral diseases such as MS and Lou Gehrig's disease since their bodies do not produce anti-B antibodies.

No matter what your blood type, eating those foods that your body can digest and metabolize efficiently, and which do not provoke a defensive immune response makes a lot of sense. We all want a free-flowing metabolism that turns the foods we eat into energy instead of excess pounds. We all want to age with grace instead of degenerative disease. Now, thanks to Dr. D'Adamo, whose theory regarding the connections among blood type, diet and disease is finding widespread acceptance due to growing scientific support, we have an important tool to help us do so.