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Frequently Asked Questions

Do you want to know more about us? Do you need more information on the Blood Type Diet? Find your answers here:

Blood Type Related Questions: All Blood Types
  The following section is an extract from Dr. D'Adamo's website ( Please visit his site if you wish to clarify any of the answers provided.  
MENU:    All Blood Types   |    Type A   |    Type AB   |    Type B   |    Type O


What is a lectin?

A protein substance commonly found in foods that binds with glycoproteins and glycolipids on the surface of animal cells causing agglutination.

Some lectins cause agglutination of erythrocytes in specific blood groups. (medical dictionary definition). Lectins also play a significant role in hormonal reactions. In lay language, this translates to very tiny molecules found in foods that selectively cause blood and other body tissues to stick together.

A lectin that causes the tissues of a person of one blood type to stick together will not necessarily have the same effect on a person of a different blood type.


How are foods determined to be in the beneficial category?

1. The food does not agglutinate that blood type.

2. The food does not raise the Urinary Indican (bowel toxicity) in that blood type.

3. The food protects against some disease with a known preference for that blood type, and does not show any negative aspects.

4. The immunological design of the digestive tract seems to indicate a distinct ability to metabolize the food well, perhaps as a result of anthropology or other variations. The food contains an enzyme known to react positively with the antigen of that blood type.

5. The food does not stimulate an opposing blood group antibody reaction.


How are foods determined to be in the avoid category?

1. The food has a lectin or other property that reacts adversely with the blood type.

2. Relative acid/alkaline balance as required to digest the food is not compatible.

3. High probability of parasite/mold populations.

4. Causes a rise in urine Indican levels (indicating bowel toxicity).


How do I get started?

There are two methods of getting started.

For the ‘Cold Turkey’ method, throw out or give away avoid foods and replace them immediately with neutral/beneficial foods.

The other choice is to eat your stocked avoids and phase them out by replacing with neutral/beneficial foods.


How long will it take to see results?
That depends on where you are starting from. Some people begin to feel better and show signs of disease remission within two weeks. Usually, it takes about two months, and in some cases, it can be as long as six months for notable results to occur. Weight loss can start in as little as two weeks or as long as two to six months, depending upon your current glandular state of health.

How long will I have to be on this diet?
Choosing foods this way represents a lifelong commitment. It is always up to you to decide what foods you eat. Some people report having adverse reactions to avoid foods after choosing beneficial & neutrals for a six month period. Others report that they have a greater tolerance for previously distressing foods. Only time will tell how you will react.

What is compliance?

1. If you are recovering from an illness or desire weight loss, then 80%-100% of your food choices should be highly beneficial.

2. If you are a healthy individual over the age of 55, 80% of foods should be beneficial.

3. If you are under 55 and healthy, 70% or more of your food choices should beneficial.

4. The remainder of your food choices should be neutral. Avoids should not be eaten.


I take medication for an illness, can I stop taking it?

NO !  Many medications are addictive and/or have delayed effects.  Do not stop without consulting the prescribing physician or other knowledgeable practitioner.


Why is the status of a whole food one value, and an extract or preparation of the food rated the opposite?
The lectin content or antigenic propensity (allergy potential) of certain foods is modified by processing. In some cases the unhealthier form (i.e processed bread) may be acceptable if heat or milling has removed the lectin from the food. Other times processing enhances the effect of a lectin, so the native form is acceptable, but the processed form is not.

Can a person's blood type change?
Only in very rare circumstances and with certain forms of cancer present. The most common cause of seemingly changed blood types is the antigen sensitivity of the chemicals used to test the blood. Drugs or other factors about your blood may cause an erroneous readings. Operator error or poor lighting can result in an incorrect interpretation of the test results.

Should I combine Choosing Foods based on Blood Type with the Zone or any other food choice program?
Some people report positive results following a combination of two plans, while others report negative outcomes. In summary, we can not answer that question.

Should I take supplements?
In general, supplements are not recommended unless there is a specific reason to take them. Some supplements should be avoided, based on blood type, as an overdose can be just as toxic, if not more so, than a deficiency. Some examples are Vitamin A, Vitamin E, Zinc and Chromium Picolinate. In a random sampling of progress reports submitted to Dr. D'Adamo, the vast majority of those with positive outcomes were not using supplements, while those taking supplements were not seeing similar positive results.

Does Rh (+/-) factor matter?
At this time, few significant differences have been noted with regard to the Rh blood type and diet. One note, O- individuals often need slightly more protein, less grain, and more careful avoidance of avoids, especially potential mold carriers.

I appear to be allergic/reactive to a highly beneficial food, what do I do?
Don't eat it. In the event that your body has been altered by drugs, surgery or disease, you may have different tolerances for food. The best thing to do in this situation is avoid the allergic foods and the avoids for your blood type. Choose as many beneficial and neutral foods as possible. This sensitivity may change over time.

An Avoid herb or supplement is recommended (by another source) for my (diagnosed) medical condition.

1. This will require some discernment on your part.

2. An herb is generally considered an avoid for a blood type due to particular negative metabolic reactions that may be induced by the herb or indirectly induced as a side effect. If possible, attempt to locate a similarly functioning herb with similar benefits.

3. Generally, a supplement is considered an avoid because it is bountiful in a well rounded, fresh food based diet for your blood type. Additional supplementation could be considered toxic.

However, if you have a diagnosed deficiency of the substance, or a medical condition shown to benefit by supplementation, then the supplement may be taken. It is always wise to consult a nutritionally knowledgeable person who can monitor your health in this situation.


What is Ezekiel bread?
Ezekiel, Essene and Manna breads are made from 100% sprouted grains, as opposed to all other commercially available sprouted grain breads which also have regular flour included in the recipe. The lectins in many grains are contained in the seed coat. The seed coat is actually metabolized by the seed/grain when it is germinated, thereby eliminating the lectin and rendering the food useable. New brand names of sprouted grain bread are continually coming to market. Always check the ingredient label for the presense of unsprouted flour or grain.

What is ghee?
Also called clarified butter, it sounds deadly to the arteries, but actually has a rather positive effect on the cholesterol and HDL's (good cholesterol). In the intestines (B and AB's especially), ghee is converted to butyrate, a short chain fatty acid which both regulates the intestinal flora and promotes the health of the colon tissue. Ghee can be made at home, or bought in health food shops or Indian gourmet stores.

Can Kelp be substituted for Bladderwrack?
No. Be sure the bottle says: 'Fucus vesiculosis.'

Aside from blood type principles; from a general health standpoint, are there any food choice tips?

Organic produce, organic dairy and free range meats are recommended. Genetically altered foods (which includes virtually all non-organic soy beans), hydrogenated oils (margarine), partially hydrogenated oils, artificial sweeteners, colors, aromas, and flavors should be avoided.

Smoked and fried foods are not recommended. Oils should be purchased and stored in light-proof containers, preferably refrigerated after opening. White flour and sugars should be eaten rarely, if at all. MSG should not be used.

Avoid aluminum cookery (it can contaminate your food with aluminum) and microwaves (they change the molecular structure of foods in unknown ways) for heating foods.


I’m (morally, ethically, religiously) opposed to eating some of the foods listed.
This subject is very complex, involving ethical and philisophical material that can not be adequately addressed in this document. We can only offer information. You are free to pick and choose which foods you eat. It is your body, and ultimately, your decision. All we can provide is information, the rest is up to you to decide.

Why are different exercises recommended for people with different blood types?

The exercise recommendations are focused on improving total systemic health, mainly the functioning of the organs, glands, immune and circulatory systems of the body; as opposed to building muscle tissue (which can be viewed as a pleasant side effect).

What strenuous exercise does for type O, yoga does for type A, and aerobic exercise does for type B and AB. Exercise recommendations are made with a general bias toward a person with a sedentary lifestyle. The link between blood type, stress and exercise is discussed in Live Right 4 Your Type.


I started to lose weight the first few weeks I choose food by blood type, then I stopped losing. What's going on?
The first thing to understand is the choosing foods by blood type is about total health. Weight loss can be a pleasant side effect of beneficial food choice. As our bodies get healthier, there are various plateaus we will go through where the glands and hormones start to reset and normalize their functions. During these periods, it is common not to lose weight. In addition, lectins blocking insulin receptors on the surface of cells do not willingly let go. Patience and 100% avoidance of all avoid foods is called for during this healing period, which can last a year or more.

What if I don't respond?

If, after three to six months of eating right for your type, you are not healthier or losing weight, there are several options to explore:

1. If you are Type A or AB, you may be one of the less common subtypes of those types. There are subtle differences in the diets, mostly relating to amounts and proportions of foods. There is little data currently available, but it may be of benefit to get one of the refined blood tests currently available. Please contact the Foundation if you would like further assistance and would consider being participant in a study.

Keep a detailed food log noting everything that you ingest and all symptoms of illness as you notice them. It is possible that you are eating hidden avoids or have an immunological sensitivity (allergy) to a particular food that is supposed to be beneficial for you. You may consider an IgG food allergy test, even though these tests have a very high rate of error. You may wish to explore other systems of eating.

2. The key is to realize that if you are not getting healthier, then you should accept responsibility, and be willing to change something about your lifestyle to continue the facilitation of your healing.

3. Fortunately, result outcomes indicate that the program is effective in about 9/10 individuals. Pretty good odds!


Can I drink beverages with meals?
It is recommended that beverages be consumed at least 1/2 hour prior to eating, and no sooner than 2 hours after eating. Drinking water during meals should be eliminated or reduced in order to keep digestive enzymes functioning at full strength. Remember to chew your food slowly and thoroughly. Enjoy the taste and don't talk while chewing.

Is aflatoxin a problem in peanuts?
Peanut and peanut butters are required to be inspected specifically for aflatoxin. It is no longer believed to be a concern in commercial preparations. It may be a problem if small private growers sell moldy nuts direct to small buyers, like health food stores, for sale as is or as peanut butter.

I've been reading about the potential dangers of soy, what's the story?

Soy is a good food if you are type A. By this it is meant that soy will not make you FEEL good if you are type A. Some of the good things soy is doing may, in fact, make you feel not so great after you eat it, but it is good for you nonetheless. Here it is the effect of soy lectin on the blood and immune system. These uncomfortable reactions are usually temporary. Making sense of the recent controversial articles about soy, phytates, aromatase and minerals:

1. Phytates are in soy.

2. Humans secrete phytase (and occasionally consume it), which is an enzyme responsible for the breakdown of phytic acid. Some animals, namely rats, have close to none of this enzyme. This means that in humans it won't bind the minerals no where near as much as rats. Phytates are converted to inositol, and phosphate in the human body which has other beneficial effects. Most "tests" are done on rats [and are not applicable to humans]. Phytic acid protects against the two biggest cancer killers in men and women, namely breast, and prostatic cancer.

3. The relatively low methionine levels in some phytochemicals such as soy, limit the synthesis of polyamines necessary for tumor growth. Methionine is problematic for type A's in other areas as well: it is linked to elevated levels of homocysteine, a significant risk factor for artery disease.

4. Genistein and daidzein, the major phytoestrogens in soy are themselves 'aromatase inhibitors. This is true of many isoflavones. Aromatase is an enzyme which converts androgens to estrogens. Aromatase is located in estrogen-producing cells including ovaries, placenta, testicular Sertoli and Leydig cells, adipose, and brain tissues. Aromatase inhibitors are increasingly the drug of choice for managing metastatic breast cancers which have retained estrogen sensitivity.

5. High levels of the enzyme aromatase stimulate estrogen sensitive cancers. The isoflavones (phytoestrogens) in soy inhibit aromatase. Another potential problem with soy is that of genetic manipulation. An ever increasing amount of soy planted in the United States has been genetically altered. 6. In addition, many commercial varieties of soy have been manipulated to increase the fat and protein content of the bean. The long term results of these manipulations are unknown, and wait to be seen. In general, organic soy has not been altered or manipulated, and products made from organic soy should be the soy of choice.


Should I avoid genetically engineered foods?
Yes! Genetic engineering moves lectin molecules from one species to another. Since lectins are the molecules that interact with our blood types, an OK food can easily become an avoid. Currently, the only way to safely avoid 'GE' foods is to choose organic.

What impact does the blood type diet have on the developing fetus during pregnancy?
Under situations of sickness, such as frequent miscarriage or whatever, the appropriate diet for the mother has worked wonderfully. We have had many patients as mothers who have followed the diet with great success. To my knowledge, the diet has resulted in no problems or reactions in these situations. Of course, everyone is different, and you might want to bring the diet to your obstetrician's attention if there are any other health problems. There should be no reactions should you conceive a type O child. This is true for a number of reasons. First the fetus is to some degree "immunologically privileged". Second, type A does no normally react to O tissue. For example, if you are type A, you could receive type O blood. Sometimes, however, type O mothers can have a problem with B and A children.

Are you an advocate of "food combining"?

I am aware that many practitioners use food combining as part of their dietary recommendations. I do not, simply because the blood type diets do specifically what food combining attempts to do non-specifically.

Proponents of food combining claim that correct food combinations are important for proper digestion, utilization, and assimilation of the nutrients our body needs to sustain life. Different foods require different digestive enzymes to aid in the digestive process - some acid, some alkaline. When acid and alkaline foods come in contact, they neutralize each other and retard digestion. If the food we eat is not properly digested, it will pass through the intestinal tract without being completely broken down, getting stuck between the crevices located in the intestinal track - thereby causing the toxic wastes to ferment and putrefy.

Critics claim that there's no evidence to support such contentions. Nearly all foods are themselves combinations. If you eat beans, for example, you're getting carbohydrates (sugars and starches), protein and fiber, among other things. Bread combines protein, carbohydrates, a little fat and many other things. A simple dish like macaroni and cheese, a peanut butter sandwich, or oatmeal with milk contains sugars, starches, protein and fat. Our digestive system handles food combinations very efficiently. The process begins in the mouth as we chew food and saliva acts upon it, beginning the breakdown of starches into sugars. Other enzymes come into play along the line, resulting in almost complete digestion and absorption of nutrients, no matter how they are combined.


I want to know what a good source of lycopene is, since tomatoes are forbidden on the A diet.
It should also be remembered that tossing a tomato into your salad is not going to give you all that much lycopene. Tomatoes have a very high water content, so not surprisingly you only find high concentrations of lycopene in tomato paste. You also find large amounts of tomato lectin in tomato paste. Research confirms that lycopene from tomatoes is absorbed much better into the bloodstream if it is first processed.

One of my friends sees a naturopathic doctor who claims that naturopathic philosophy is based exclusively on vegetarian-based diets.

This association is so ingrained in the belief systems of some individuals that to even suggest appropriate consumption of animal products might actually enhance some individuals health places me somewhere between 'public enemy number I' and the devil in the eyes of several of my critics.

I have even had some individuals within my own profession suggest that I had abandoned the core of naturopathic medicine by advocating good quality meat for individuals of certain blood types. Often a good question to ask is, 'what does the evidence show?' Naturopathic medicine developed from the water cure movement of Europe. Theodor Hahn is credited as being the first of the pioneers of this water cure movement to integrate vegetarian dietetic principles. He was convinced that a meat-free diet would prolong life. In fact he was so convinced of the value of a vegetarian diet that he spent a great deal of his professional life writing books and pamphlets on the subject and was the editor of a magazine called 'The Vegetarian'. He died of colon cancer at the age of 59.


How can it be that wheat isn't good for anyone? Hasn't it been a staple in man's diet for thousands of years?

Wheat as we know it in the millennia of this era is not the same as it was at the very beginning. The genetics of wheat show that its development is very complex.

Today grain has developed from three naturally occurring groups of wheat. Through natural crossings, mutations, and natural selection these have evolved into all the many varieties of wheat grown worldwide. In essence, the 'hard wheat' that we eat nowadays has a protein content as high as 13%, versus the more ancient wheats which had a protein content of, at most, about 2%. Increasing the protein content has had the effect of making wheat a viable source of protein for many people around the world, but has also increased the allergenic (gliandin, gluten and lectin containing), pro-inflammatory and metabolic-blocking portions of the plant almost seven-fold.

Aside from the under-investigated metabolic effects of wheat lectin, classic hypersensitivity to wheat is found in many infants and adults. Reactions are often localised in the GI tract. In a study of asthmatic patients, 46% (children) and 34% (adults) were found to have IgE to wheat as tested by Pharmacia & Upjohn, Diagnostics CAP System. In another study, specificity for wheat allergen using the same system was 98%.

Wheat allergy was found to cause a persistent food hypersensitivity in atopic dermatitis patients (75% remained intolerant). In 102 grass-pollen allergic children, 12% were found to be allergic to wheat.


I can do the program for a while, but then I feel that my will begins to slip and I'm binging again.
The trick to surviving failure is to refuse to be disillusioned by it. It is the gradual effects of disillusionment ('retreat after defeat') that sap the will and prevent us from enduring to the end in order to triumph over our challenges. The first step in this process: Don't degrade your failures by stripping them of their spiritual value. This is why most successful people are actually experts in failure.

Why should all types avoid HOG?
Hog is very "A-like" immunologically, which makes it an avoid if you happen to have antibodies to the blood type A antigen, like type B's and O's do. Paradoxically enough, hog also has an antibody (iso-hemmaglutinin) in its tissues which reacts to the A antigen, so it should be avoided for this reason by A's and AB's as well.

Are the amounts of each grouping of foods merely for weight loss?
The amounts of foods recommended are intended to offer general guidance only. It is much more important to eat in accordance with the highly beneficial and avoid foods recommended for your blood type.

What about wheat grass for type A?
The sprouting of wheat into wheat grass destroys the lectin that is problematic in wheat. Sprouting also beneficially changes the nutrient profile of this grain, resulting in a nutrient-dense, enzyme-rich superfood. Because of these factors, I consider wheat grass to be an excellent addition to the diet for all blood types. As far as an amount, use your own judgement. Because of the concentrated nature of this food, a little goes a long way, so if you have not enjoyed wheat grass juice before, start with a smaller amount.

Does cooking destroy or neutralize lectins?
In some cases, yes. In other cases, such as tomatoes, the lectin activity is enhanced by cooking. The recommendations for foods are inclusive of whether the food is eaten raw or cooked, unless explicitly stated otherwise.

Does sprouting destroy or neutralize lectins?
In some cases, yes. In other cases, such as alfalfa sprouts, the lectin activity is enhanced by sprouting. The recommendations for foods are inclusive of whether the food is eaten sprouted or cooked, unless explicitly stated otherwise.

Some people on other internet boards claim that blood testing for secretor status is superior to the saliva test. Is that true?
Dr. D'Adamo had this to say about differences in secretor testing: "Having done 5000 Lewis typing tests in the clinic over the last 15 years, and about 400 salivary inhibition studies, I can safely say that saliva testing is more accurate than blood. The reason being that the agglutinations that are used to determine Lewis types are very delicate (weak antibody reaction) and can easily be misinterpreted, unlike ABO which makes a big glop that you cannot miss (strong antibody). I've even seen conflicting results from two different MedPath labs, especially if the staff is not trained well enough."

There is no proof that eating for your blood type works, and it may in fact be dangerous. Is that true?
There is ample evidence that the Blood Type Diets are effective. In over 5000 self-reported outcomes,  between 82-86%  (depending on blood type) of those responding reported improvement in a systemic (i.e. digestive, cardiovascular, immunologic, etc.) aspect of their health. What is most profound about these results is that the degree of success on each particular (A, B, O, AB) diet are within percentage points of each other, even though several of the diets are diametric opposites. This certainly verifies the idea that there is no one single 'perfect diet,' but rather several inherently healthy diets, each more healthy in some than others. Also worth noticing are the uniformly very low percentages of people reporting any worsening of pre-existing conditions, typically less that 3% of all responders. It would be difficult, if not impossible, to find similar results with any other  single diet theory.

It seems that there are no health advantages to being a non-secretor! Do you have any guesses why 20 percent of the population would be burdened with this condition?
You're right. It appears the vast majority of difficulties are associated with a non-secretor allele. Whether or not this is a purely detrimental influence, I cannot say at this point. There are a couple positives: You tend to have less lectin-related food problems, and your white blood cells tend to be more aggressive when combatting some types of cancer. On the other hand, there are a lot of metabolic problems associated with a non-secretor. Whereas non-secretors may make up between 15 to 20 percent of the population, they probably account for up to 70 percent of the people I see in my clinic -- principally because of metabolic problems, gut permeability issues, and chronic infectious disease susceptibilities.

Interestingly, what appears to be the natural selection of the non-secretor gene may have been a rather left-handed health benefit. It appears that non-secretor children who carried the gene for diabetes tended to die in utero or in very early life. Sadly enough, this may have been a benefit to our ancestors. For, in the opposite situation, with the child having lived but having been chronically ill, they would have represented quite a drain on the resources of the community. Perhaps it acted as a type of suicide gene.

Though one of the nice things about knowing you're a non-secretor, or that you're Type A or Type O, is that despite all the bad news, at least you know it! Since the really bad news would be to not know that there was bad news! [laughs] I only wish I knew more bad news about the other blood types.
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