Ask the Doctor – July 2007

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Dear Doctor Rona,

I hope you won’t mind answering a question. In your book you recommend York Nutritional Lab in the U.K. to test for food intolerances. Since it has been several years since that book was published, I looked for a lab here in the U.S. I found 2. One is Optimum Health Resource Laboratories (IgG ELISA Food Intolerance Test) who say they were part of York until recently, and the other is ALCAT Worldwide who uses a test that measures white blood cell reactions to foods.

My question: Are you familiar with both tests, and would you recommend one over the other for someone with Rheumatoid arthritis? I am sure that my diet makes a big difference in how I feel and was dreading doing an
elimination diet. I didn’t know that there are tests available for intolerances – this information in your book has given me a lot of hope. I do hope for an answer even though you’ve warned that you might just toss this… Thank you.

Sincerely, Margaret Pasach


I am familiar with both tests and tend to favor the York Nutritional Lab one over the ALCAT mostly because of the better scientific support documentation for the IgG ELISA test.  There is, however, one test that’s better. Meridian Valley Laboratory offers a combined IgG with IgE ELISA test, thus measuring both delayed and immediate food allergies. See

To understand which types of tests are valid and reliable in determining food and chemical allergies, it is important to realize that there are basically only two kinds of adverse reactions, delayed and immediate.  Unfortunately, this basic concept is still not firmly grasped by the majority of the population, conventional allergists and pediatricians.

The following is basic science fact:

Immediate (Type I) reactions:

– produce allergic symptoms (e.g. wheezing, swelling, choking, pain) that commonly occur two hours or less after consumption of the offending foods or chemicals; the food or chemical reaction is usually well known to individual.
– have only 1 or 2 foods involved in causing allergic signs and symptoms which are usually severe; these are the well known, often life-threatening reactions to peanuts, shellfish and strawberries.
– create food or chemical reactions triggered by even trace amounts of foods; it may take only the odor of cooked lobster to elicit intense allergic reactions (including anaphylaxis) in sensitive individuals.
– are common in children and rare in adults.
– are usually a permanent or ³fixed² allergy; these food reactions can be lessened by vitamin, mineral and herb supplementation.
– are associated with the IgE family of antibodies and can be verified by a skin test or a blood test called the IgE RAST or ELISA test.


– produce allergic reactions usually within 24 hours, and sometimes up to 4 days, after consumption of the offending foods or chemicals
– have 3 to 20 foods involved in causing allergic signs and symptoms which are usually chronic (joint and muscle pain, fatigue, depression, psoriasis, etc.) and are hidden or unsuspected by the victim
– create food or chemical reactions after consuming larger amounts of foods, often in multiple feedings; a single food challenge might not cause any allergic reactions to occur
– are very common in children and adults with over 50 medical conditions and 200 symptoms triggered, worsened or caused by the allergic reactions
– are usually reversible within 3 to 6 months with a combination of food elimination and nutritional supplement therapy (antioxidants, enzymes, herbs, etc.)
– are not associated with the IgE family of antibodies but could be related to antibodies from the IgA, IgM and IgG antibody families (Type II reactions), immune complexes which involve antigen, antibody and the
inflammatory chemical called Complement (Type III reactions) or cell-mediated immunity (Type IV reactions); these types of reactions can be verified by blood tests known as the ELISA/Act test or the non-IgE RAST
or ELISA tests.

Most food allergic people are unaware of their food allergies because, in a delayed reaction, the symptoms may occur many hours or days after ingestion.

To further complicate things, if an allergic food has not been eaten for several months and is accidentally ingested, a reaction may happen fairly quickly.  For example, if a person is allergic to milk, each time he or she drinks milk, he or she feels temporarily better. When the person stops drinking milk, he or she might initially feel worse for several days but, usually within 7 to 10 days, starts feeling better.  After avoiding dairy products for 6 weeks, a milk challenge given in large amounts may cause symptoms to be dramatically reproduced (wheezing, coughing, runny nose, irritability, etc.).

Delayed food allergies often create a complex blend of symptom masking effects, withdrawal reactions and symptom reproduction with food reintroduction.  People with food allergies can behave as if they were addicted to foods.  For example a reaction to being withdrawn from milk can be stopped or lessened by a second glass of milk.  This is the same that happens to the alcoholic¹s unpleasant withdrawal symptoms when he is given another glass of whiskey. People often crave the foods which cause of their symptoms and this is one fairly reliable way of knowing what should be taken out of their diets to improve their immune status.


Since over 90% of all food allergies are of the delayed onset type, skin tests and the IgE RAST will miss detecting the vast majority of food allergies.  Nevertheless, conventional doctors continue to use them for that purpose and often conclude that the patient³ does not have any food allergies² even though no tests were ever done for delayed hypersensitivity food reactions. For this and other reasons, those suffering from asthma, arthritis, eczema, irritable bowel syndrome, chronic sinusitis, hay fever, recurrent respiratory tract infections and other diseases are told that food allergies have nothing to do with their illness and that only a lifetime of steroid, antibiotic and antihistamine drugs will help.

There are many good tests that help detect food and chemical reactions. Although considerable confusion exists about which is the best laboratory test, most agree with the accuracy and reliability of the elimination – provocation technique described by food allergy pioneers such as Drs. William Crook and Doris Rapp.  This technique involves eliminating whole classes of foods for several days, then adding them back noting reactions.

Workable variations of this are the Coca Pulse Test which does not require a practitioner and sublingual food challenges which are usually administered by practitioners of environmental medical specialists.  Some of these procedures would not be appropriate for people suffering from severe pain syndromes or those who do not have the time or stamina to experiment with their diets.  On the other hand, there is something to be said for experiencing the effects of allergenic foods in reproducing symptoms.

The elimination – provocation technique ultimately empowers sufferers to control symptoms with simple diet changes.


The basic concept behind this type of food allergy testing is to follow a hypoallergenic diet for three weeks, eliminating the most common food allergens and thereafter challenging the body with the eliminated foods one by one noting the reactions. During the 3 week elimination diet, symptoms (wheezing, runny nose, etc.) improve in the majority of people who suffer from food allergies.  If the reintroduction of certain foods causes a reproduction of the symptoms, the person is probably allergic to those foods. This diet works only if all the foods to be discontinued are done so abruptly or ³cold turkey².  Easing into this diet slowly or some other compromise does not work nearly as well.  In severely ill people (cancer, heart disease, brittle juvenile diabetics, cortisone-dependent asthmatics or other life-threatening problems), it is not recommended that this approach be tried without close supervision by a medical doctor. Use common sense and the advice of your naturopath or doctor before attempting this on your own. A sample elimination diet follows here.


Some foods and beverages should be eliminated regardless of suspected allergies because of their harmful effects on health in general. These are all foods containing sugar, white flour, caffeine, chocolate, alcohol, hydrogenated fats (margarine, fried foods) and food additives of many kinds.

Alcohol – found commonly in herbal and homeopathic tinctures and some prescription liquids (replace with non-alcoholic equivalents)

Beef and pork – burgers, steaks, hot dogs, cold cuts contain chemicals, additives, drugs, hormones and carcinogens too numerous to list

Caffeine – colas, soft drinks, chocolates, coffee, tea

Citrus – oranges, lemons, limes, grapefruits, tangerines, mandarins

Corn – anything with corn oil, vegetable oil, margarine, corn syrup, sweeteners with corn, dextrose, glucose, popcorn, tortillas, corn chips; read labels:vegetable oil usually refers to corn oil

Dairy Products – milk, cheese, butter, yogurt, ice cream, sour cream, cottage cheese; read labels carefully because casein (milk protein), whey, caseinate or anything containing these are dairy products and are even found in some soy based products sold commercially; most margarines contain both corn and casein

Eggs – both whites and yolks and anything made with eggs like quiche, French bread, pancakes, waffles, egg substitutes

Food additives – processed, packaged and canned foods containing artificial colors, flavorings, preservatives, texturing agents, artificial sweeteners, sulfites

Known allergens – includes any foods known to produce symptoms (e.g. peanuts causing respiratory distress, etc.); do not eat any known reactive food just because it does not appear on this list

Seeds and nuts – most have high mold content, peroxidized fats and other associated allergy problems; raw almonds, walnuts, sesame and their nut butters are exceptions but only in those children known to have had no reactions to them

Sugar in any form – table sugar, candies, candy bars, cookies, pies, cakes, biscuits, sucrose, glucose dextrose, corn syrup, fructose, maltose, levulose; pure, unprocessed honey, maple syrup or barley malt in small amounts (1 to 3 tsps.) daily is allowed in some children at the discretionof the family doctor or pediatrician; avoid dried fruit because of mold and other additive content which could evoke allergic reactions

Tap water – contains many chemicals, chlorine, fluoride, toxic heavy metals and sometimes parasites; use distilled or mineral water sold in glass, not plastic, bottles; reverse osmosis water from home filtration equipment is acceptable

Vitamin and mineral supplements – only those without wheat, corn, yeast and other additives are permitted

Wheat – most pastas, breads, baked goods, cereals, semolina, Durham, gravies, spelt, pizza; read labels: flour usually mans wheat


Vary the diet as much as possible because one can become allergic to foods eaten too often, especially those eaten on a daily basis.

Beans (Legumes) – kidney beans, lima beans, black beans, soybeans, tofu, lentils, chick peas, green peas, string beans; soak all dried beans overnight and pour off the water and rinse beans before cooking; read labels for additives or prohibited foods if using canned beans

Cereals – oat meal, oat bran, puffed rice, millet; use dilute apple juice, soy milk, almond milk or rice milk which has no corn oil or casein added; these types of products are found in many health food stores or groceries

Fish, Poultry and Fowl – trout, salmon, halibut, cod, shark, swordfish, mackerel, herring, tuna, sole, turkey, chicken are good protein sources if organic ³free range² source and packed in spring water like salmon and tuna; canned shellfish (lobster, crab, shrimp) contain sulfites and other additives unless noted otherwise on the labelling

Fruit – all except citrus and dried fruits, ideally of an organic source

Grains – rice cakes, rye crackers (read labels because many rye products contain wheat), buckwheat Soba noodles, amaranth, quinoa; flours made from rice, potato, buckwheat and beans; avoid spelt due to its similarity to wheat

Lamb – hypoallergenic for most children

Spices, Condiments, Miscellaneous – sea salt and pepper in moderation is acceptable; sugar-free catsup, garlic, onions, kelp powder, wheat free tamari sauce, cayenne, curry and whatever other pure herbs in powder form known not to produce allergic reactions

Vegetables – all are permitted except corn; ideal vegetables are organic source


While following this diet a small amount of weight loss can occur in the first week as the fluid retained by the body as a reaction to the allergic foods leaves the system.  The lost weight is temporary and not an issue provided calories are also not restricted.  If not enough of the permitted food is eaten, low blood sugar symptoms can develop.  These include irritability, headaches, behaviour problems, fatigue and lightheadedness.

Withdrawal reactions occur in about 25% of people within a few days of starting the elimination diet.  Some common withdrawal reaction symptoms are flu-like illness, fatigue, headaches, a ravenous appetite, temper tantrums and other behaviour abnormalities. In most cases, these symptoms disappear within 5 days.  If withdrawal symptoms are too severe to tolerate, antidotes one can use instead of giving in to the cravings are buffered vitamin C powder and bicarbonate powder (ideally one containing a mixture of potassium, sodium, calcium and magnesium bicarbonate).  Some doctors recommend Alka Seltzer® or Alka Seltzer Gold® but, since these contain aspirin, there could be allergic reactions in some children who are allergic to aspirin.


Three weeks after following the elimination diet, testing of individual foods can be attempted provided symptoms have either improved substantially or disappeared.  If this did not happen then it¹s possible that the diet was incorrectly followed or that some allergic food or foods not on the list were eaten.  In such cases, if food allergies are still suspected, alternative testing is more appropriate.

Pure organic food sources only should be tested.  For example, do not use a chocolate bar to test for chocolate since chocolate bars are composites of dairy, wheat, corn and dozens of other foods and chemicals. Only one food per day should be tested in relatively large amounts.  If the reintroduction of foods reproduces the symptoms, the child is probably allergic to those foods.  If headaches, fatigue, nasal congestion, upset stomach, joint pains or other symptoms are caused by the food in question, it should be eliminated from the diet for at least 6 months.  In cases of autoimmune diseases like juvenile rheumatoid arthritis, it is better to test foods every 48 hours because of the delayed reaction to foods so often seen in these disorders.  In testing, if one is not sure of whether or not there was a positive reaction to a specific food, take it out of the diet and retest it about a week later. Testing foods the child never eats is unnecessary and so is testing for known food allergies.


Once you and your health care practitioner have established the most likely allergic foods, these and anything containing them are eliminated while everything else eaten is put in a four day rotation.  Eating foods that one is not allergic to can develop into food allergies if eaten over and over again on a daily basis.  For example, dairy allergic children who go off milk, cheese and other dairy products who substitute soy milk and other soy products and then go on to consume soy products on a daily basis eventually become allergic to soy.  A four day rotation diet prevents this phenomenon, but many children can get away with eating the foods less frequently than every 4 days. There are many examples of published 3 and 4 day rotation diets and one example is provided in the appendix section of this book. After 6 to 12 months, the allergic foods can be retested.  If no reactions are noted, these foods can be eaten once every 4 days along with the other permitted foods.  If there is still an allergic reaction, the food is kept out of the diet again for another 6 months.


There are no conclusive studies comparing the accuracy and reliability of different types of food allergy/sensitivity tests.  Muscle testing, electroacupuncture tests like VEGA and Interro combined with the subject¹s personal experience with different foods and professional counselling have been documented to improve the lives of countless thousands.

Acupuncture and homeopathy work for a great majority of the human race but there are people who do not benefit from any aspect of these methods of diagnosis. The same can be said for various in-vitro tests like the Cytotoxic test, the RAST and ELISA blood tests.  One thing for sure is that the standard skin scratch tests fail to detect the correct food sensitivities.

The elimination – provocation test, when appropriate, combined with the IgG-IgE ELISA is currently the state of the art in detecting hidden food allergies. The scientific literature certainly supports this approach.  The advantage of the blood test is that it is capable of detecting delayed food allergies belonging to all of the delayed reaction subgroups (Types II, III and IV allergies).  Blood testing for food and chemical reactions allow physicians to take blood in their offices which are then couriered to the labs offering the service.

This in no way invalidates other forms of testing which may work equally well for selected people.  In the future, with more research, time and practitioner experience, the question of test validity and reliability will become clearer.  In the meanwhile, people who eliminate the offending foods from their diets reduce the allergic load on the immune system. This gives the body the opportunity to repair damaged tissues like the joints, muscles or the lining of the respiratory tract.  Those who are allergic to dust, ragweed, pollens and other inhalant allergies can then be more tolerant to environmental allergens and less likely to suffer from severe allergic reactions that previously needed strong drugs for control.

Much of the appeal of the different blood tests for food allergies is the convenience of having the test results without going through the rigors of an elimination diet.  The disadvantage of the blood tests is the cost (from $100 to $1200 depending on the number of foods tested and the lab/physician fees).  Although more and more health insurance companies are providing coverage for the blood tests, many doctors still have concerns about the reliability of this form of testing for hidden food allergies.

Although blood testing for food allergies has been improved considerably over the years, different types of blood testing done on the same patient still yield different results in an unacceptable number of cases.   More research and refinements are needed for higher accuracy.

Please email your questions to

Zoltan Rona, M.D., M.Sc.
1366 Yonge St. Suite 201
Toronto, ON
M4T 3A7

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