DIAGNOSING FOOD CHEMICAL INTOLERANCE
Diagnosing food chemical intolerance (such as salicylate intolerance) is done by using the Low Chemical Diagnostic Elimination Diet. This diet has a number of names. The actual diet is the Royal Prince Alfred Hospital (RPAH) Diagnostic Elimination Diet but it is also called the Failsafe Elimination diet which refers to the strict level of the RPAH diet. This is the only useful testing available.
Other tests such as IgG (immunnoglobulin G- the most common type of antibody found in our blood stream) antibody tests are not validated or recommended by the scientific community. All of us produce IgG when we eat foods and it is not related to food intolerance or any disease. The test results simply reflect what foods you have eaten recently- not necessarily what foods are causing your symptoms (1).
There are so many tests out there that are marketed as being able to be used, often with a hefty cost but they have been shown to produce misleading results and lead to ineffective therapy.
The end result is many people unnecessarily avoiding foods and do not get to the bottom of what is causing their reactions.
Information on these methods is available on the Australasian Society of Clinical Immunology and Allergy (ASCIA) website:
RPAH Elimination Diet
The Diagnostic Elimination Diet was developed by the Royal Prince Alfred Hospital (RPAH) specifically to diagnose food chemical intolerance: salicylates, amines, glutamates and certain food additives known to cause food reactions in sensitive people or children.
The RPAH Diagnostic Elimination Diet is the gold standard approach for identifying and managing suspected food chemical intolerance.
The process has 3 steps:
STEP 1: Elimination. Clean your diet from the food chemicals to see if this can eliminate or significantly reduce symptoms.
STEP 2: Challenges to identify which groups of food chemicals are causing your symptoms.
STEP 3: Bring back safe foods then reintroduce foods to find your threshold.
3. Safe foods in & find your threshold
Removal of foods high in salicylates, amines and glutamates as well as certain food additives.
Additionally: any of the following may also be eliminated as required:
Whole foods: wheat or gluten, dairy, soy and any allergy foods already identified
High FODMAP foods
Salicylates in the environment also need to be reduced such as switching to low scent hygeine products, low chemical toothpaste, avoidance of air fresheners or essential oils, and a review of any non essential medications which may contain salicylates and preservatives.
For example most liquid pain relief for children are very high in flavours and preservatives which will often cause symptoms in sensitive babies and children.
The elimination diet is implemented for a minimum of 2 weeks but more commonly for around 4 weeks. Mistakes and diet tweaking lengthen the elimination phase. Mistakes are common, and almost expected in the early stages of the diet.
Most improvements are seen between 3 - 4 weeks.
By the end of the 1st week or more commonly the 2nd week, there may be re-occurence of symptoms (withdrawals).This is an indicator the diet is working, and the withdrawals will subside. Not everybody has withdrawals.
2. FOOD CHALLENGES
Once you have been able to achieve elimination of or significantly reduced symptoms for 5 days in a row, a series of challenges are undertaken to carefully identify which of the eliminated food types are actually causing your symptoms.
You now have a safe diet (your new normal) against which you can test out the different foods/ food chemicals.
Any whole foods eliminated such as wheat, milk or soy
Food chemical challenges (salicylates, amines, glutamates all done separately)
Food additives (antioxidants, food colours, propionates, nitrates & nitrites, sorbates, benzoates, sulphites- all done separately)
FODMAPs (if a combined elimination)
Any other food items or personal items you want to test out
The challenge time is a brilliant opportunity to test out anything you were not sure you have reacted to. Maybe you want to test buckwheat, or a probiotic, or something else that you would like to take which is known to have some level of food chemicals.
The results of the challenges gives you a unique profile of your food sensitivities.
3. SAFE FOODS BACK IN & FIND YOUR THRESHOLD
The food challenges that you passed with flying colours are put back into the diet for 3-4 weeks to confirm that the stable baseline continues, i.e. no deterioration in symptoms.
Then it is a matter of your threshold for the chemicals you did react to. This means foods you reacted to through the challenges are reintroduced to see how much you can safely eat without triggering your symptoms.
The amounts introduced depend on how sensitive you are. The amount eaten is increased in either amount (dose) or frequency (how many times eaten) in a week, and carefully increased over time to find where your individual threshold lies.
DIFFERENT LEVELS OF RESTRICTION
Depending on the type and severity of your reactions and your preferences, there are 3 levels of restriction possible:
strict (the FAILSAFE diet is all about the strict level)
The strict and moderate elimination includes challenges while the more simple elimination (just cutting back on the highest sources of food chemicals in your diet as well as food additives) does not include challenges.
For a mild elimination- only very high foods containing food chemicals are eliminated (much simpler).
The simple elimination is more suitable for people:
- who only have milder symptoms
- who may be travelling
- for whom dietary restriction is very difficult
FODMAPs may also be eliminated depending on your particular sensitivities and preferences.