Elimination diet
Encyclopedia
An elimination diet is a method of identifying foods that an individual cannot consume without adverse effect
s. Adverse effects may be due to food allergy
, food intolerance
, other physiological mechanisms (such as metabolic or toxins), or a combination of these. Elimination diets typically involve entirely removing a suspected food from the diet for a period of time from two weeks to two months, and waiting to determine whether symptoms resolve during that time period. In rare cases, a health professional may wish to use an oligoantigenic diet
to relieve a patient of symptoms they are experiencing.
Common reasons for undertaking an elimination diet include suspected food allergies and suspected food intolerance
s. An elimination diet might remove one or more common foods, such as eggs
or milk
, or it might remove one or more minor or non-nutritive substances, such as artificial food coloring
s.
An elimination diet relies on trial and error
to identify specific allergies and intolerances. Typically, if symptoms resolve after the removal of a food from the diet, then the food is reintroduced to see whether the symptoms reappear. This challenge-dechallenge-rechallenge
approach is particularly useful in cases with intermittent or vague symptoms.
The terms exclusion diet and elimination diet are often used interchangeably in the literature, and there is no standardised terminology. The exclusion diet can be a diagnostic tool or method used temporarily to determine whether a patient’s symptoms are food-related. The term elimination diet is also used to describe a "treatment diet", which eliminates certain foods for a patient.
Adverse reactions to food can be due to several mechanisms. Correct identification of the type of reaction in an individual is important, as different approaches to management may be required. The area of food allergies and intolerances has been controversial and is currently a topic that is heavily researched. It has been characterised in the past by lack of universal acceptance of definitions, diagnosis and treatment.
In 1978 Australian researchers published details of an 'exclusion diet' to exclude specific food chemicals from the diet of patients. This provided a basis for challenge with these additives and natural chemicals. Using this approach, the role played by dietary chemical factors in the pathogenesis of chronic idiopathic urticaria (CIU) was first established and set the stage for futute DBPCT trials of such substances in food intolerance studies.
Food allergy
is defined as an immunological hypersensitivity which occurs most commonly to food proteins such as egg, milk, seafood, shellfish, tree nuts, soya, wheat and peanuts. Its biological response mechanism is characterized by an increased production of IgE
(immunoglobulin E
) antibodies.
A food intolerance
on the other hand does not activate the individual's immune response system. A food intolerance differs from a food allergy or chemical sensitivity because it generally requires a normal serving size to produce symptoms similar to an IgE
immunologic response. While food intolerances may be mistaken for a food allergy, they are thought to originate in the gastrointestinal system. Food intolerances are usually caused by the individual’s inability to digest or absorb foods or food components in the intestinal tract. One common example of food intolerance is lactose intolerance
.
Elimination diets are useful to assist in the diagnosis of food allergy and pharmacological food intolerance. Metabolic, toxic and psychological reactions should be diagnosed by other means.
and the radioallergosorbent test RAST
to detect specific IgE
antibodies to specific food proteins and aero-allergens. However false positive results occur when using the SPT
when diagnosis of a particular food allergen is hard to determine. This can be confirmed by exclusion of the suspected food or allergen from the patient's diet. It is then followed by an appropriately timed challenge under careful medical supervision. If there is no change of symptoms after 2 to 4 weeks of avoidance of the protein then food allergy is unlikely to be the cause and other causes such as food intolerance should be investigated. This method of exclusion-challenge testing is the premise by which the Elimination Diet is built upon, as explained in the sections below.
Vega testing, a bioelectric test, is a controversial method that attempt to measure allergies or food or environmental intolerances. Currently this test has not been shown to be an effective measure of an allergy or intolerance.
Food intolerance due to pharmacological reaction is more common than food allergy and has been estimated to occur in 10% of the population. Unlike a food allergy, a food intolerance can occur in non-atopic individuals. Food intolerances are more difficult to diagnose since individual food chemicals are widespread and can occur across a range of foods. Elimination of these foods one at a time would be unhelpful in diagnosing the sensitiveity. Natural chemicals such as benzoates and salicylates found in food are identical to artificial additives in food processing and can provoke the same response. Since a specific component is not readily known and the reactions are often delayed up to 48 hours after ingestion, it can be difficult to identify suspect foods. In addition, chemicals often exhibit dose-response relationships and so the food may not trigger the same response each time. There is currently no skin or blood test available to identify the offending chemical(s), and consequently, elimination diets aimed at identifying food intolerances need to be carefully designed. All patients with suspected food intolerance should consult a physician first to eliminate other possible causes.
While on the elimination diet, records are kept of all foods eaten, medications taken, and symptoms that the patient may be experiencing. Patients are advised that withdrawal symptoms can occur in the first weeks on the elimination diet and some patients may experience symptoms that are worse initially before settling down.
While on the diet some patients become sensitive to fumes and odours, which may also cause symptoms. They are advised to avoid such exposures as this can complicate the elimination and challenge procedures. Petroleum products, paints, cleaning agents, perfumes, smoke and pressure pack sprays are particular chemicals to avoid when participating in an elimination diet. Once the procedure is complete this sensitivity becomes less of a problem.
Clinical improvement usually occurs over a 2 to 4 week period; if there is no change after a strict adherence to the elimination diet and precipitating factors, then food intolerance is unlikely to be the cause. A normal diet can then be resumed by gradually introducing suspected and eliminated foods or chemical group of foods one at a time. Gradually increasing the amount up to high doses over 3 to 7 days to see if exacerbated reactions are provoked before permanently reintroducing that food to the diet. A strict elimination diet is not usually recommended during pregnancy, although a reduction in suspected foods that reduce symptoms can be helpful.
Reasons for undertaking an elimination diet may vary from patient to patient, as some types of elimination diets are not out of medical necessity but completely by choice. Some of the most common elimination diets include
If any results are doubtful the testing is repeated, only when all tests are completed is a treatment diet determined for the patient. The diet restricts only those compounds to which the patient has reacted and over time liberalisation is attempted.
In some patients food allergy and food intolerance can coexist, with symptoms such as asthma, eczema and rhinitis. In such cases the elimination diet for food intolerance is used for dietary investigation. Any foods identified by SPT or RAST as suspect should not be included in the elimination diet.
Adverse effect
In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. If it results from an unsuitable or incorrect dosage or...
s. Adverse effects may be due to food allergy
Food allergy
A food allergy is an adverse immune response to a food protein. They are distinct from other adverse responses to food, such as food intolerance, pharmacological reactions, and toxin-mediated reactions....
, food intolerance
Food intolerance
Food intolerance or non-allergic food hypersensitivity is a term used widely for varied physiological responses associated with a particular food, or compound found in a range of foods....
, other physiological mechanisms (such as metabolic or toxins), or a combination of these. Elimination diets typically involve entirely removing a suspected food from the diet for a period of time from two weeks to two months, and waiting to determine whether symptoms resolve during that time period. In rare cases, a health professional may wish to use an oligoantigenic diet
Oligoantigenic diet
An oligoantigenic diet is a diet with the least possible risk of allergic reaction. It is used to eliminate food allergies as the cause of a particular illness. It has been used to treat Crohn's disease , migraine and ADHD ....
to relieve a patient of symptoms they are experiencing.
Common reasons for undertaking an elimination diet include suspected food allergies and suspected food intolerance
Food intolerance
Food intolerance or non-allergic food hypersensitivity is a term used widely for varied physiological responses associated with a particular food, or compound found in a range of foods....
s. An elimination diet might remove one or more common foods, such as eggs
Egg allergy
Egg allergy is a type of food allergy. It is a hypersensitivity to dietary substances from the yolk or whites of eggs, causing an overreaction of the immune system which may lead to severe physical symptoms for millions of people around the world....
or milk
Milk allergy
A milk allergy is a food allergy, an adverse immune reaction to one or more of the constituents of milk from any animal...
, or it might remove one or more minor or non-nutritive substances, such as artificial food coloring
Food coloring
Food coloring is a substance, liquid or powder, that is added to food or drink to change its color. Food coloring is used both in commercial food production and in domestic cooking...
s.
An elimination diet relies on trial and error
Trial and error
Trial and error, or trial by error, is a general method of problem solving, fixing things, or for obtaining knowledge."Learning doesn't happen from failure itself but rather from analyzing the failure, making a change, and then trying again."...
to identify specific allergies and intolerances. Typically, if symptoms resolve after the removal of a food from the diet, then the food is reintroduced to see whether the symptoms reappear. This challenge-dechallenge-rechallenge
Challenge-dechallenge-rechallenge
Challenge-dechallenge-rechallenge is a medical testing protocol in which a medicine or drug is administered, withdrawn, then re-administered, while being monitored for adverse effects at each stage...
approach is particularly useful in cases with intermittent or vague symptoms.
The terms exclusion diet and elimination diet are often used interchangeably in the literature, and there is no standardised terminology. The exclusion diet can be a diagnostic tool or method used temporarily to determine whether a patient’s symptoms are food-related. The term elimination diet is also used to describe a "treatment diet", which eliminates certain foods for a patient.
Adverse reactions to food can be due to several mechanisms. Correct identification of the type of reaction in an individual is important, as different approaches to management may be required. The area of food allergies and intolerances has been controversial and is currently a topic that is heavily researched. It has been characterised in the past by lack of universal acceptance of definitions, diagnosis and treatment.
History
The concept of the elimination diet was first proposed by Dr. Albert Rowe in 1926 and expounded upon in his book, Elimination Diets and the Patient's Allergies, published in 1941.In 1978 Australian researchers published details of an 'exclusion diet' to exclude specific food chemicals from the diet of patients. This provided a basis for challenge with these additives and natural chemicals. Using this approach, the role played by dietary chemical factors in the pathogenesis of chronic idiopathic urticaria (CIU) was first established and set the stage for futute DBPCT trials of such substances in food intolerance studies.
Definitions
'Food hypersensitivity' is an umbrella term which includes food allergy and food intolerance.Food allergy
Food allergy
A food allergy is an adverse immune response to a food protein. They are distinct from other adverse responses to food, such as food intolerance, pharmacological reactions, and toxin-mediated reactions....
is defined as an immunological hypersensitivity which occurs most commonly to food proteins such as egg, milk, seafood, shellfish, tree nuts, soya, wheat and peanuts. Its biological response mechanism is characterized by an increased production of IgE
Immunoglobulin E
Immunoglobulin E is a class of antibody that has been found only in mammals. IgE is a monomeric antibody with 4 Ig-like domains...
(immunoglobulin E
Immunoglobulin E
Immunoglobulin E is a class of antibody that has been found only in mammals. IgE is a monomeric antibody with 4 Ig-like domains...
) antibodies.
A food intolerance
Food intolerance
Food intolerance or non-allergic food hypersensitivity is a term used widely for varied physiological responses associated with a particular food, or compound found in a range of foods....
on the other hand does not activate the individual's immune response system. A food intolerance differs from a food allergy or chemical sensitivity because it generally requires a normal serving size to produce symptoms similar to an IgE
Immunoglobulin E
Immunoglobulin E is a class of antibody that has been found only in mammals. IgE is a monomeric antibody with 4 Ig-like domains...
immunologic response. While food intolerances may be mistaken for a food allergy, they are thought to originate in the gastrointestinal system. Food intolerances are usually caused by the individual’s inability to digest or absorb foods or food components in the intestinal tract. One common example of food intolerance is lactose intolerance
Lactose intolerance
Lactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...
.
- Metabolic food reactions are due to an inbornInborn error of metabolismInborn errors of metabolism comprise a large class of genetic diseases involving disorders of metabolism. The majority are due to defects of single genes that code for enzymes that facilitate conversion of various substances into others...
or acquired errors of metabolism of nutrients such as in diabetes melitus, lactase deficiency, phenylketonuriaPhenylketonuriaPhenylketonuria is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase , rendering it nonfunctional. This enzyme is necessary to metabolize the amino acid phenylalanine to the amino acid tyrosine...
and favism. Toxic food reactions are caused by the direct action of a food or additive without immune involvement.
- Pharmacological reactions are generally to low molecular weight chemicals which occur either as natural compounds such as salicylatesSalicylate sensitivitySalicylate sensitivity, also known as salicylate intolerance, is any adverse effect that occurs when a normal amount of salicylate is introduced into a person's body...
, amines, or to artificially added substances such as preservatives, coloring, emulsifiers and taste enhancers including glutamate (MSG). These chemicals are capable of causing drug-like (biochemical) side effects in susceptible individuals. - Toxins may either be present naturally in food or released by bacteria or from contamination of food products.
- Psychological reactions involve manifestation of clinical symptoms caused not by the food but by emotions associated with the food. The symptoms do not occur when the food is given in an unrecognizable form. Although an individual may have an adverse reaction to a food, this is not considered a food intolerance.
Elimination diets are useful to assist in the diagnosis of food allergy and pharmacological food intolerance. Metabolic, toxic and psychological reactions should be diagnosed by other means.
Diagnosis
Food allergy is principally diagnosed by careful history and examination. When reactions occur immediately after certain food ingestion then diagnosis is straight forward and can be documented by using carefully performed tests such as the skin prick test (SPT)Skin allergy test
Skin allergy testing is a method for medical diagnosis of allergies that attempts to provoke a small, controlled, allergic response. -Process:A microscopic amount of an allergen is introduced to a patient's skin by various means:...
and the radioallergosorbent test RAST
RAST test
A RAST test is a blood test used to determine to what substances a person is allergic. This is different from a skin allergy test, which determines allergy by the reaction of a person's skin to different substances....
to detect specific IgE
Immunoglobulin E
Immunoglobulin E is a class of antibody that has been found only in mammals. IgE is a monomeric antibody with 4 Ig-like domains...
antibodies to specific food proteins and aero-allergens. However false positive results occur when using the SPT
SPT
SPT may refer to:Organizations* Sony Pictures Television, American television company* Strathclyde Partnership for Transport, organization which plans public transport* SPTrans, a large urban public transport authority in São Paulo, Brazil* St...
when diagnosis of a particular food allergen is hard to determine. This can be confirmed by exclusion of the suspected food or allergen from the patient's diet. It is then followed by an appropriately timed challenge under careful medical supervision. If there is no change of symptoms after 2 to 4 weeks of avoidance of the protein then food allergy is unlikely to be the cause and other causes such as food intolerance should be investigated. This method of exclusion-challenge testing is the premise by which the Elimination Diet is built upon, as explained in the sections below.
Vega testing, a bioelectric test, is a controversial method that attempt to measure allergies or food or environmental intolerances. Currently this test has not been shown to be an effective measure of an allergy or intolerance.
Food intolerance due to pharmacological reaction is more common than food allergy and has been estimated to occur in 10% of the population. Unlike a food allergy, a food intolerance can occur in non-atopic individuals. Food intolerances are more difficult to diagnose since individual food chemicals are widespread and can occur across a range of foods. Elimination of these foods one at a time would be unhelpful in diagnosing the sensitiveity. Natural chemicals such as benzoates and salicylates found in food are identical to artificial additives in food processing and can provoke the same response. Since a specific component is not readily known and the reactions are often delayed up to 48 hours after ingestion, it can be difficult to identify suspect foods. In addition, chemicals often exhibit dose-response relationships and so the food may not trigger the same response each time. There is currently no skin or blood test available to identify the offending chemical(s), and consequently, elimination diets aimed at identifying food intolerances need to be carefully designed. All patients with suspected food intolerance should consult a physician first to eliminate other possible causes.
Elimination diet
The elimination diet must be comprehensive and should contain only those foods unlikely to provoke a reaction in a patient. They also need to be able to provide complete nutrition and energy for the weeks it will be conducted. Professional nutritional advice from a dietitian or nutritionist is strongly recommended. Thorough education about the elimination diet is essential to ensure patients and the parents of children with suspected food intolerance understand the importance of complete adherence to the diet, as inadvertent consumption of an offending chemical can prevent resolution of symptoms and render challenge results useless.While on the elimination diet, records are kept of all foods eaten, medications taken, and symptoms that the patient may be experiencing. Patients are advised that withdrawal symptoms can occur in the first weeks on the elimination diet and some patients may experience symptoms that are worse initially before settling down.
While on the diet some patients become sensitive to fumes and odours, which may also cause symptoms. They are advised to avoid such exposures as this can complicate the elimination and challenge procedures. Petroleum products, paints, cleaning agents, perfumes, smoke and pressure pack sprays are particular chemicals to avoid when participating in an elimination diet. Once the procedure is complete this sensitivity becomes less of a problem.
Clinical improvement usually occurs over a 2 to 4 week period; if there is no change after a strict adherence to the elimination diet and precipitating factors, then food intolerance is unlikely to be the cause. A normal diet can then be resumed by gradually introducing suspected and eliminated foods or chemical group of foods one at a time. Gradually increasing the amount up to high doses over 3 to 7 days to see if exacerbated reactions are provoked before permanently reintroducing that food to the diet. A strict elimination diet is not usually recommended during pregnancy, although a reduction in suspected foods that reduce symptoms can be helpful.
Reasons for undertaking an elimination diet may vary from patient to patient, as some types of elimination diets are not out of medical necessity but completely by choice. Some of the most common elimination diets include
- VeganismVeganismVeganism is the practice of eliminating the use of animal products. Ethical vegans reject the commodity status of animals and the use of animal products for any purpose, while dietary vegans or strict vegetarians eliminate them from their diet only...
, where an individual removes all animal products from the diet, including meat, dairy, fish, eggs, and even honey. Many will refuse to use any item that has been produced by an animal, like leather or fur clothing. - VegetarianismVegetarianismVegetarianism encompasses the practice of following plant-based diets , with or without the inclusion of dairy products or eggs, and with the exclusion of meat...
, which tends to be a less extreme version of veganismVeganismVeganism is the practice of eliminating the use of animal products. Ethical vegans reject the commodity status of animals and the use of animal products for any purpose, while dietary vegans or strict vegetarians eliminate them from their diet only...
, with options ranging from an ovo-lacto vegetarian, a person who will consume no meatMeatMeat is animal flesh that is used as food. Most often, this means the skeletal muscle and associated fat and other tissues, but it may also describe other edible tissues such as organs and offal...
, but will consume dairy products and eggsEgg (food)Eggs are laid by females of many different species, including birds, reptiles, amphibians, and fish, and have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen , and vitellus , contained within various thin membranes...
, a Pescetarian that consumes no meat products except fish and shellfish, or even a flexitarian who will consume a mostly vegan diet, but eats meat and other animal products on occasion. - Gluten-free, a diet where all grains that contain gluten are eliminated from the diet, including wheatWheatWheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
, kamut, speltSpeltSpelt is a hexaploid species of wheat. Spelt was an important staple in parts of Europe from the Bronze Age to medieval times; it now survives as a relict crop in Central Europe and northern Spain and has found a new market as a health food. Spelt is sometimes considered a subspecies of the...
, barleyBarleyBarley is a major cereal grain, a member of the grass family. It serves as a major animal fodder, as a base malt for beer and certain distilled beverages, and as a component of various health foods...
, ryeRyeRye is a grass grown extensively as a grain and as a forage crop. It is a member of the wheat tribe and is closely related to barley and wheat. Rye grain is used for flour, rye bread, rye beer, some whiskeys, some vodkas, and animal fodder...
, and potentially oatsOATSOATS - Open Source Assistive Technology Software - is a source code repository or "forge" for assistive technology software. It was launched in 2006 with the goal to provide a one-stop “shop” for end users, clinicians and open-source developers to promote and develop open source assistive...
, though there is some controversy on this grain. This is the only medically accepted treatment for patients who have Celiac disease and has some inconclusive studies linked to decreasing symptoms of autismAutismAutism is a disorder of neural development characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child is three years old. Autism affects information processing in the brain by altering how nerve cells and their...
.
Challenge testing
Challenge testing is not carried out until all symptoms have cleared or improved significantly for five days after a minimum period of two weeks on the elimination diet. The restrictions of the elimination diet is maintained throughout the challenge period. Open food challenges on wheat and milk can be carried out first, then followed by challenge periods with natural food chemicals, then with food additives. Challenges can take the form of purified food chemicals or with foods grouped according to food chemical. Purified food chemicals are used in double blind placebo controlled testing, and food challenges involve foods containing only one suspect food chemical eaten several times a day over 3 to 7 days. If a reaction occurs patients must wait until all symptoms subside completely and then wait a further 3 days (to overcome a refractory period) before recommencing challenges. Patients with a history of asthma, laryngeal oedema or anaphylaxis may be hospitalised as inpatients or attended in specialist clinics where resuscitation facilities are available for the testing.If any results are doubtful the testing is repeated, only when all tests are completed is a treatment diet determined for the patient. The diet restricts only those compounds to which the patient has reacted and over time liberalisation is attempted.
In some patients food allergy and food intolerance can coexist, with symptoms such as asthma, eczema and rhinitis. In such cases the elimination diet for food intolerance is used for dietary investigation. Any foods identified by SPT or RAST as suspect should not be included in the elimination diet.
Tax Credit
Some countries offer a tax credit available to a patient if they are on a specific elimination diet. More commonly a tax credit will be issued to an individual suffering from Celiac Disease who is required to maintain a gluten free diet for life. Countries involved in this type of medical tax credit include Canada and the U.S.See also
- Food IntoleranceFood intoleranceFood intolerance or non-allergic food hypersensitivity is a term used widely for varied physiological responses associated with a particular food, or compound found in a range of foods....
- Lactose intoleranceLactose intoleranceLactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...
- Gluten sensitivityGluten sensitivityGluten sensitivity belongs to a spectrum of disorders in which gluten has an adverse effect on the body. It can be defined as a non-allergic and non-autoimmune condition in which the consumption of gluten can lead to symptoms similar to those observed in coeliac disease or wheat allergy .Gluten...
- Salicylate sensitivitySalicylate sensitivitySalicylate sensitivity, also known as salicylate intolerance, is any adverse effect that occurs when a normal amount of salicylate is introduced into a person's body...
- Multiple chemical sensitivityMultiple chemical sensitivityMultiple chemical sensitivity is a chronic medical condition characterized by symptoms the affected person attributes to exposure to low levels of chemicals. Commonly suspected substances include smoke, pesticides, plastics, synthetic fabrics, scented products, petroleum products and paints...
- Sodium phosphatesSodium phosphatesSodium phosphate is a generic term for the salts of sodium hydroxide and phosphoric acid. They are:* sodium dihydrogen phosphate, commonly termed monosodium phosphate, , is also known as "sodium phosphate, monobasic"....
- AllergyAllergyAn Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
- Allergy testing
- Canada's Food Guide
- Food guide pyramidFood guide pyramidA food guide pyramid is a triangular or pyramid-shaped nutrition guide divided into sections to show the recommended intake for each food group. The first food pyramid was published in Sweden in 1974. The most widely known food pyramid was introduced by the United States Department of Agriculture...