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The elimination diet is not a new concept, although it has gained popularity in recent years. It was first proposed in 1926 by Albert Rowe to combat food allergies. (1)
An elimination diet is a method of testing the reaction to specific foods and eliminating the ones that cause health problems, such as allergies and food intolerances.
Note: even if the problem-causing foods are identified, they don’t necessarily have to be eliminated from your diet.
For instance, if you are sensitive to caffeine but like drinking coffee, tea or eating chocolate, elimination diet can help you establish how much of these foods you can enjoy without experiencing nasty symptoms.
One of the application of the elimination diet is in the treating of ADHD symptoms.
Food allergy and food intolerance
Food allergy is an immune response, after exposure to allergens.
Although many foods may cause an allergic reaction, the most common allergens are eggs, cow’s milk, nuts, soy, wheat and shellfish.
The common reactions include urticaria, swelling of the mouth, airway problems (breathing difficulties), rhinitis, diarrhea or vomiting.
Food allergens are also known to cause neurologic responses, such as headaches, nervousness, anxiety and confusion.
Food intolerance is a non-immunological response to foods that may be caused by hypersensitivity to food additives (e.g. MSG) or enzyme deficiency (e.g. lactose intolerance).
The most common symptoms of food intolerance are gastrointestinal difficulties, headache, mood changes and fatigue.
The elimination diet is usually used for foods or food additives that cause allergies or food sensitivities.
Main forms of elimination diets
Although there are many variations of the elimination diet, they all follow the same process.
- The diet is followed for a period of time, to see if the symptoms disappear.
- Once the symptoms disappear, specific foods are then re-introduced to test if the symptoms return.
The elimination diets fall into one of the following three forms (1):
- Single food exclusion diet
In a single food exclusion diet, one food suspected of causing problems (e.g. eggs or milk) is removed from the diet.
If the symptoms subside or disappear, it indicates that this specific food needs to be eliminated from the diet.
If the food was the main source of certain nutrients (e.g. milk as a source of calcium), then a substitute food should be introduced to avoid deficiencies.
This is a quick test that is easy to implement and the results can be seen quickly.
- Multi-food exclusion diet
A multi-food exclusion diet is used where a group of foods that may cause problems, such as allergies, are excluded.
An example of this method is a six-food elimination diet that targets six of the most common allergens: cow’s milk protein, eggs, wheat, soy, nuts and seafood. ((https://www.ncbi.nlm.nih.gov/pubmed/28877359, https://www.uwhealth.org/healthfacts/nutrition/553.pdf
Since there is only a small group of foods to test, this elimination diet not last long, as in the case of the “Few foods diet” (next point).
- A few foods diet (oligoantigenic diet).
A few foods diet is the most effective method to identify multiple foods that cause allergies.
The diet starts with only a few foods that are known as low allergenic and less commonly consumed, such as venison, quinoa, rice and pears.
Due to such restrictions, it must be done with the close supervision of a qualified health professional to avoid nutritional deficiencies.
This method is very lengthy, since it starts with a small number of basic foods. and then safe foods need to be re-introduced to reach a healthy, balanced diet.
For this reason, “a few foods diet” is the hardest to follow and requires strict adherence.
The few foods diet has been used successfully in ADHD therapy.
Examples of specific elimination diets are:
- Gluten free diet – used effectively in the treatment of Celiac disease and non-celiac gluten sensitivity
- Gluten and casein-free diet used in autism treatment – Food coloring and food additive free diet (Feingold diet or Kaiser Permanente diet) that has been used in the treatment of ADHD.
- Low-Fodmap elimination diet – a diet that avoids certain carbohydrates that can cause gastrointestinal symptoms in IBS patients. Examples of FODMAPs; lactose, fructose, sorbitol, fructans and GOS.
- 6 food elimination diet eliminates cow’s milk, soy, eggs, wheat, peanuts and tree nuts and seafood.
- The elimination diet has three forms: single food exclusion (only one food is eliminated), multi-food exclusion (a group of specific foods is eliminated) and oligoantigenic diet (most of the foods are eliminated, leaving the safest)
- The elimination diet is used to identify foods that cause health problems
Elimination diet process
The elimination diet consists of the following steps:
- Register what you eat (optional but very helpful)
First, it is important to detail what the current diet consists of to have a better idea what foods may be causing the issues.
This step is often omitted. However, it is useful before you start the test.
A diet diary written over an entire week, including the weekend, would be the minimum required to be thorough.
Some sources suggest five days. However, you should include every day of the week, since there may be some days of the week that your diet differs.
- Eliminate the suspect foods and additives
Remove all the foods or food additives that are most likely to cause a specific reaction.
In the case of the multi-food exclusion diet, you may need to remove a group of foods, such as the six main allergens.
In the case of “a few foods diet,” you may need to remove all but the most basic foods known to be low allergenic.
Once these foods are removed, it is expected that the symptoms should reduce or disappear.
If there is no change, it may be assumed that the symptoms are caused by factors other than the eliminated foods.
The foods are usually removed for a period of two to four weeks. This is enough time for the symptoms to be reduced or to disappear.
Food allergy symptoms manifest shortly after exposure to them, while food sensitivity reaction may occur after a period of time. Therefore, it is harder to detect and takes longer to complete the test.
If the symptoms disappear after removing the suspect foods, it indicates that one or more of these foods were the cause of the negative reactions.
One of the suspect foods is then introduced and the symptoms monitored.
If the symptoms return, the re-introduced food is placed on a black list and eliminated from the diet. After the symptoms have subsided, another suspect is introduced.
If the symptoms don’t come back on the first day, the diet is continued without changes for the next few days to make sure that the reaction is not delayed.
If there is no reaction, this food is placed on the safe food list and the next suspect food is introduced.
The process is then repeated for the other suspect foods or additives.
- The method of the elimination diet involves first removing the suspect foods to eliminate the specific symptoms, then re-introducing them one by one, to test if the symptoms return.
- Individual foods that causes problems are then identified and removed from the diet permanently.
- The result is a healthy, balanced diet with a variety of nutritious foods but free from foods that causes allergies and sensitivities.