How effective is an elimination diet in the treatment of EoE?
There are two basic types of elimination diets. One, commonly referred to as a ‘directed’ elimination diet is based on the results from an initial skin prick or patch allergy test. The other is the more often prescribed empirical or ‘non-directed’ elimination diet.
A diet based on allergy testing will not result in an improvement of symptoms for most people as these tests are generally not specific enough to identify EoE-causing allergens and rarely achieve their objective.
The empirical, ‘non-directed’ elimination diet is therefore probably the best choice for people with EoE. The one used most often and most effectively in both children and adults is the six-food elimination diet (SFED). In one study, inflammation of the oesophagus was successfully reduced (defined as a significant reduction in eosinophil numbers in the oesophageal mucosa) with an improvement in symptoms in more than 70% of people following this diet.9
How do elimination diets work?
The SFED involves the complete elimination of the six foods which are the mostly like to cause an allergic reaction (dairy products, wheat, eggs, soy, nuts and fish/seafood) from the diet and then waiting six to eight weeks. At this time, you will have an endoscopy to confirm (by biopsy) that there has been a significant reduction in eosinophil numbers/inflammation in the lining of the oesophagus (the mucosa).
Once this is confirmed, one food group is re-introduced at a time. You will have another endoscopy and another biopsy two to four weeks later to see if there has been a significant increase in eosinophil numbers/inflammation. If there has been an increase, then that food is considered to be allergenic (causing an allergic reaction) and it is permanently removed from your diet. Once it has been removed (known as a ‘wash-out’), you wait another four to eight weeks to allow the eosinophil count/inflammation to decline.
If there is no significant increase in eosinophil numbers in the oesophagus, then the food is most unlikely to be allergenic and you can keep eating this specific food. A new food will then be reintroduced without delay, with another endoscopy and biopsy performed two to four weeks later. This process is repeated until each food is confirmed allergenic or not. For some people with EoE, many foods are allergenic .10
To help you adapt to your diet, seeing a dietitian with knowledge in EoE is helpful in achieving the best possible outcomes. Over several visits, they can offer suggestions and advice on how to avoid foods which are determined to be allergenic to you.
As an alternative to the SFED diet, you might be given the so-called ‘step-up’ elimination diet to reduce the number of endoscopies you would otherwise need by about 20%. At first, only two food groups (usually dairy and wheat, the most likely to be allergenic) are eliminated and then reintroduced using the same procedure described above. However, this doesn’t mean the other four foods are not allergenic and ultimately you might need an SFED to ensure this procedure is as wide-ranging as possible. Even then, there are foods not included in the SFED that could cause allergic reactions in some people with EoE.
What are the limitations of elimination diets?
It can take up to a year to identify the foods that cause an allergic reaction and some people need up to eight endoscopic examinations to get a definite result. When you’re on an empirical elimination diet, it’s important to make several appointments with a dietitian for advice and support. Being on such a strict diet for a very long time can have a negative impact on your quality of life.