Allergy Testing: Hidden Food Allergy

Most people are familiar with a classic food allergy response — a severe reaction to a particular food. It’s easy to identify the hives, throat swelling, or difficulty breathing after eating foods like peanuts or shrimp. This is one kind of a systemic, violent response to a type of food, which can be life threatening and the treatment is to avoid the food life-long.

Harder to identify, but no less significant are hidden food allergies, which may be present, but it incites a much more subtle response in the individual. There are many people who do feel they have a problem with foods of some sort, but it is not clear-cut or easy to define. Often a person will have a diagnosis like irritable bowel syndrome (IBS), which, to most physicians, does not have a specific cause. The symptoms of IBS are gas, bloating, diarrhea, and constipation or some combination of these. Often symptoms occur for no known reason, and when stress is factored in, it may cause a worsening of symptoms. People diagnosed with irritable bowel syndrome undergo many tests, like colonoscopies, X-rays, and stool sampling, which, to the relief but also to the frustration of the patient, sometimes do not reveal worrisome findings like inflammation or structural problems. This is one type of an as-yet unexplained body system reaction, which may be an underlying marker of a bigger problem, such as a hidden food allergy.

Other common clues to a hidden food allergy can involve skin rashes, eczema, joint aches and pains, dizziness, chronic post-nasal drip, asthma and chronic headaches, including migraines. A hidden food allergy can cause bladder symptoms such as frequent irritation and discomfort with urination, while no infection is found.

While many people may suspect that food triggers or causes symptoms, it is often hard to pinpoint the offending food. The reason is the nature of food allergy and sensitivity.

Why do Food Allergies Exist?

Our immune system is a complex system, composed of many different cells which work in an amazing balance to produce antibodies and histamine and other chemicals to kill invading organisms that can make us ill, like bacteria or viruses. In the case of a food allergy, an antibody is made by the immune system to one or more foods. People can have a genetic predisposition to the development of allergy, for example, if your parents are highly allergic people, you are more likely to have issues with allergies of all sorts. It does appear that food allergy rates are increasing in this country, and some suspicion lies with the increase in the processing of food with chemicals which stimulate an abnormal immune process. Combined with this is the fact that more and more of our food supply consists of genetically modified foods. The heavy use of pesticides and other environmental toxins also likely plays a role in stimulating and challenging the immune system to the point that it reacts to substances our bodies do not need to fight — like foods.

Another theory behind the rising incidence of food allergy is that more and more gluten, which is found in the grains wheat, barley and rye, are in our food supply. A large percent of the population has a genetic predisposition to be sensitive to gluten and in these individuals the ingestion of gluten can cause the body to make antibodies to their own tissues, such as the tissues that line the small intestine. This is a pathologic process called auto-immunity which damages the small intestine. The intestine can become inflamed and dietary proteins end up leaking out of the gut and into the bloodstream where antibodies are made. The blood reacts to foreign, partially undigested and toxic food particles in the bloodstream, and systemic inflammation begins to occur, causing headaches, chronic pain, sinus congestion, and the list goes on.

Hidden Food Allergy or Sensitivity Is Hidden

Hidden food allergies are so difficult to detect and diagnose because they often occur with foods that you eat all the time. The most common foods to cause hidden allergies are wheat, milk, soy, corn, yeast, eggs, and citrus. The most common foods that cause severe anaphylactic reactions (not hidden) are peanuts, tree nuts, and shellfish. Reviewing the list of common hidden food allergens, it is easy to see that these seven foods are in most of the foods we eat. Particularly, if someone relies on restaurant or processed food, they will ensure a steady daily dose of all of these foods every day.

So, if for example, a person is allergic to milk (not lactose intolerance, but a true milk allergy) and for that person their symptom is a response in the digestive tract, they will always have a mild state of unwell in their abdomen. They may have frequent gas or bloating, constipation or diarrhea. Occasionally, their symptoms can be more severe, but there is no obvious food to blame, because nothing new appeared in the diet.

Allergy Masking

When you eat food to which you are sensitive on a regular basis, you do have symptoms, but they are masked. A masked symptom is present at a low level and may not be so terribly bothersome that the person would seek out immediate medical attention. Often if medical attention is sought for these vague symptoms, no real answer is able to be given. Once that food is avoided for approximately 21 days, the

reaction symptom becomes unmasked, and to most people, the response is very obvious when they reintroduce the offending food.

The Food Elimination and Re-challenge test is the ‘gold standard’ method of diagnosing hidden food sensitivity. In our practice, we recommend avoiding the common allergenic foods for 3-4 weeks and then reintroducing those foods into the diet, one at a time. Often people will report that their gastrointestinal symptoms resolve after a few days, years of chronic post nasal drip ceases or years of muscular pain improves. Chronic fatigue has been alleviated after a brief time of avoiding reactive foods.

On the re-challenge of the food, the patient will have a more severe and more immediate reaction, as the patient’s symptoms are no longer masked. The abstinence period of 21 days eliminates the masking that is present and the reaction to the food allergy is felt with its full force. Many times people interpret this to mean that their food allergies are getting worse. The allergy is not worse, but the full brunt of it is just now being felt, and now it can be identified as the cause of a certain symptom, and the food can be identified and avoided.

A hidden food allergy can also be diagnosed by blood tests which detect an antibody in the blood to a specific food. Blood testing is not as accurate as the food elimination and re-challenge because not all allergy reactions are due to antibodies. However, they are a helpful tool for the diagnosis of hidden food allergies. I tell patients that if they have a reaction when they eat a certain food but their blood tests show no antibody, they still have a problem with that food and need to avoid it. Blood tests that pick up IgG antibody levels show a more mild type of food sensitivity. IgE tests can detect more severe types of food allergy. These tests are scored indicating a mild allergy as 1+ and more severe as 4+ or higher.

Must I avoid reactive foods forever?

Certainly food allergies that are severe and that cause breathing problems, hives, and throat swelling need to be eliminated from the diet. However, what do we do with these more mild food allergies that are annoying but not life threatening?

Often with hidden food allergy, if a food is eliminated for several months, it can be reintroduced without symptoms as long as it is not eaten too frequently. This is the rationale behind a 4-day rotation diet where, after a period of elimination of a food for several months, it can be eaten again as long as it is not consumed more than once every four days. This definitely requires some planning of meals but can allow someone who has many food sensitivities to successfully get back into a more normal pattern of eating. The intestine does heal if aggravating foods are avoided and this is important so that new sensitivities to different foods do not develop. If the intestine is still inflamed, antibodies can develop to newly introduced foods. Hypoallergenic probiotics and digestive enzymes can be helpful to all patients who have food allergy issues to aid in intestinal healing.

The primary treatment of food allergy is avoidance, and it can become extremely difficult to do. Many of my patients have allergies to multiple common foods such as wheat, egg, yeast and milk. It is very challenging to avoid these foods if traveling or eating at restaurants or other’s homes. The important thing to remember is that the majority of the time avoiding reactive foods leads to better health and wellness overall. Many people experience reactions after ingesting a certain food that convinces them not to eat those foods no matter what. It depends on how willing a person is to continue feeling better and enjoying wellness free of food allergens, and developing a lifestyle that allows for it.