Q. Glen, What is a Eliminations / Exclusion Diet?
A. An exclusion diet, or elimination diet, is a diet in which likely allergens or other foods to which a patient may be sensitive are avoided. Elimination diets are commonly used both to confirm other diagnostic tests, like RAST tests and prick tests, as well as to pinpoint possible food intolerances. They are also a diagnostic tool for inflammatory bowel disease.
Exclusion diets should only be tried under a doctor's care. These diets are generally safe, but allergists are able to recommend when elimination diets are appropriate, advise how they can be effectively carried out, and interpret their results properly.
While other diagnostic tests rarely return false negatives (that is, if they indicate that a patient is not allergic to a given food, the patient has at least a 95 percent likelihood of indeed not being allergic), they are fairly likely to return false positives. Unless the patient experienced anaphylaxis before taking diagnostic tests, allergists will often recommend an elimination diet (to see if symptoms improve) followed by a double-blind food challenge test (one in which neither the doctor nor the patient is aware of whether the patient is eating the likely allergen) to confirm test results.
As a diagnostic tool in its own right. In some cases --- for example, when a child who is being exclusively breastfed shows symptoms of a food allergy --- it can be difficult to discern which foods might be causing allergic symptoms. An elimination diet in which likely allergens are removed and then added back one by one may be useful as a diagnostic tool.
Your allergist should give you clear instructions, but the mechanics will work in one of two ways, depending on whether the likely allergen is known. In cases where a particular food is suspected to cause an allergic reaction or an intolerance, that food is strictly avoided for a period of time. If avoiding the food causes the symptoms to subside, and ingesting some in a double-blind food challenge causes them to return, that normally indicates allergies.
When the cause of allergic symptoms is unclear, allergists use several different types of elimination diets to narrow down the range of foods that might be causing symptoms. Since 90 percent of food allergies are caused by the eight most common food allergens, one option is to eliminate any of these foods that may be problematic. This type of diet does not have a specific name. If this doesn't yield results, your doctor may recommend a "few foods" diet or a "rare foods" diet.
This diet is exactly what its name sounds like: a small number of foods which are deemed unlikely to cause an allergic reaction are eaten for a period of time. If this diet is used as a diagnostic tool, then foods are gradually added back one at a time to see if symptoms reappear. Examples of foods commonly used on this diet include lamb, rice, turkey, and pears, all of which are considered unlikely to cause allergic reactions.
The theory behind the rare foods diet is simple. It excludes all foods that are currently part of the patient's diet in favor of foods the patient has either never eaten at all, or has never eaten regularly. This is on the theory that foods that are not a regular part of the diet are unlikely to cause ongoing allergic symptoms. Otherwise, rare foods diets are very similar to few foods diets.
In addition to their use as a diagnostic tool, exclusion diets are commonly used for patients with eczema. Many patients with eczema have food allergies or sensitivities, and patients will commonly eliminate these foods to alleviate eczema (although a recent study showed that this type of diet was far overused).
The biggest challenge of an elimination diet -- especially a rare foods or few foods diet -- is finding ways to prepare foods without using ingredients that you may have used frequently -- flour, milk, and margarine are some of the common foods you may not be allowed to use. Your doctor may provide you with resources and recipes along with your instructions for carrying out the diet. Numerous online sites offer dietetic recipes.
Elimination diets, especially if they need to be carried out for a long period of time, can be risky in infants and young toddlers because it can impede their growth and development. This is also true for both breastfeeding mothers and their babies; long-term elimination diets have been associated with failure to thrive in infants and nutritional inadequacy in mothers. If you have any questions about the adequacy of your diet, a dietitian or nutritionist with expertise in allergy issues is an ideal professional to advise you.
Some researchers have also expressed concern that long-term diets that eliminate foods that cause minor immediate reactions, when used as a treatment for disorders like eczema whose connections to food allergies are complicated, may oversensitize the body to allergens and raise the risk of anaphylaxis. Your allergist can advise you about the risks and benefits in your case.Any personal health questions or problems mental or physical or before starting any diet or exercise program.Please consult your physician !
Wishing You Great Health!
Glen Edward Mitchell
Any questions? Ask Glen