Intolerance to Food & Food Sensitivity: The Basics

An intolerance to food, also called a food sensitivity can wreak havoc on the body - causing chronic ailments, persistent weight gain, digestive illness, migraines, and more. Find out more here about what exactly a food sensitivity is, and why we're hearing so much about it.

Food Sensitivity vs. Food Allergy

Part of the confusion about food sensitivity comes from the use of the word “allergy.” Allergy is vaguely described as an immune response to a substance to which we would not normally expect the body to have a response. Cat dander, peanuts, and shellfish immediately come to mind as allergens. There is no inherent reason for the body to treat these substances as health threats, yet it does.

Food sensitivities, which are also called food intolerance, or delayed food allergy, are also a type of allergy in the truest sense of the word: they are an immune response to a substance (food) to which we would not normally expect the body to have a response.

Food intolerance is separate from a classic food allergy in many ways. First, the two are mediated by different groups of antibodies. The classic food allergy that is associated with hives, swelling, and in severe cases, anaphylaxis, is determined by a set of antibodies called IgE (immunoglobulin E). These antibodies act quickly, and do those sorts of terrible inflammatory things we all recognize: watery eyes, runny nose, itching, swelling, and more.

In contrast, food sensitivities are mediated by a set of antibodies called IgG (immunoglobulin G). These antibodies also mount an immune response against food, and have an inflammatory effect on the body. The major difference is that the onset of symptoms could be up to 72 hours after exposure, and symptoms come in a wide variety of flavors: headaches, digestive upset, general inflammation, skin irritation, fatigue, depression, and more.

There are also food intolerances that are related to metabolic or enzyme dysfunction, such as lactose intolerance - when a person does not produce the enzyme required to properly digest milk products. These non-allergy-mediated food intolerances will not be discussed here.

Since many food intolerances go unnoticed and undiagnosed, the most disturbing symptoms can appear after a lifetime of aggravation. In this case, food intolerances manifest themselves as irritable bowel syndrome, rheumatoid arthritis, migraines, psoriasis, or any other number of chronic ailments.

Often medical professionals know physically what is happening during these illnesses, but do not know why the body has begun to act this way. As a result, when food sensitivities are not identified, the treatments range from acceptance and tolerance, to a lifetime regimen of prescriptions.

Which Foods are Causing These Effects?

Nearly any food can cause an immune response in an individual if that person’s body treats it as an invader or a threat. Gluten sensitivity is one of the most common food intolerances, followed by sensitivity to dairy, wheat, corn, soy, egg, and citrus. It is estimated that 1 out of every 16 people is gluten intolerant.

Researchers speculate that the increase in gluten sensitivity could be due to the increased levels of gluten in the grain products consumed. Gluten is a protein that acts as the elastic in breads to give it that nice, airy texture. Since consumers like light, airy bread, we have gradually bred wheat to contain more and more gluten.

This biochemical change in wheat is probably compounded by the sheer volume of grains that we eat in comparison to our ancestors. Most Americans eat wheat products at every meal and snack. It is believed that repeated exposure to anything can induce an allergy. Many can attest to acquiring an animal allergy after years of owning that animal, for example. Asthma and wheat allergy are considered occupational hazards of working in a bakery (J Bogdanovic et al, 2006).

An intolerance to food can appear at any age, and against any food.

Even though celiac sufferers produce antibodies against gluten, gluten intolerance is separate from celiac disease, with a different blood profile and different symptoms.

Since celiac has been widely accepted as an allergic response to gluten, researchers and medical professionals alike have become more open-minded to the possibility that other inexplicable illnesses may also be caused by reactions to food.

Along Comes Science

Recently, the scientific community has turned its focus to food sensitivities as a source of chronic conditions, and the results are astounding. Scientists are discovering what gluten intolerant patients have been telling them for years: that food intolerance is its own illness separate from celiac, but certainly no less important.

Scientists have shown that intolerance to food may underlie a multitude of health complaints.

Read More About Ailments Associted with Delayed Food Allergies
Scientists are validating what food intolerant people inherently know: some foods in some people cause terrible symptoms.

How Do You Test for Food Intolerance?

Intolerance to food is most easily and thoroughly tested through an IgG ELISA blood test. These tests screen for the presence of IgG antibodies (not IgE) against specific foods.

According to a 2010 review of the food allergy testing possibilities, G.E. Mullin and colleagues say "immunoglobulin G (IgG)-based testing showed promise, with clinically meaningful results. It has been proven useful as a guide for elimination diets, with clinical impact for a variety of diseases."

In the absence of a blood test, intolerance to food is often identified through elimination diets, where a potentially offending food is removed completely from the diet for 2-8 weeks. Then the food is reintroduced with specific note of any symptoms. If multiple foods are suspected, then they are all eliminated, and reintroduced 3-5 days apart from one another.

In many cases elimination diets can be helpful, and identify foods that are aggravating. In other cases the symptoms do not respond to an elimination diet, or return in an unpredictable pattern.

Also, in cases where individuals have multiple food sensitivities, it may be difficult to identify and eliminate all of the foods from the outset.

Some practitioners use a scratch test to identify food sensitivities. This test is successful at identifying some food intolerances, but is typically limited by the number of foods that are screened - screening 96, 115, or 200 foods is unreasonable with a scratch test, unlike an blood IgG test. A study in December of 2010, showed that skin prick testing was not a reliable test for children with gastrointestinal symptoms (Cudowska B & Kaczmarski M, 2010).

In 2011, a study in the International Archives of Allergy and Immunology showed that skin irritations such as hives do not respond well to the results of IgG blood tests. In these cases of skin disorders, scratch testing or atopy patch testing may be more appropriate.

If You Have a Food Sensitivity, Then What?

Like any allergy, most people with and intolerance to food feel their best when they avoid the allergen. It is advised to remove the allergen from the diet for 2-6 months and monitor symptoms before reintroducing offending foods.

Depending on the severity of the food intolerance (the body may produce more or fewer antibodies against a given food), some people can eat sensitive foods a few times each week, or with a digestive enzyme without complaint. IgG test results are typically presented as a range of antibody levels so that the relative severity of the intolerance can be easily assessed - another benefit of blood testing over scratch testing.

In addition to digestive enzymes, probiotics, l-glutamine, and general support of the immune system and adrenal system are helpful for many. Individuals can work with a holistic practitioner to improve digestion, remove any excess burden on the immune system, and strengthen the adrenal gland.

Candida albicans overgrowth can make individuals susceptible to food allergies by compromising the intestinal lining (N Yamaguchi et al, 2006). Therefore, consider addressing any possible candida overgrowth as a way of managing food sensitivities.

A licensed acupuncturist may also be able to ease some food sensitivities by improving digestion and balancing the immune system and adrenal system. Classic homeopathy with a focus on constitutional therapy can help address the immune system’s hyperactivity.

Research shows that children under 3 years old "outgrow" approximately 44% of food sensitivities, on average. That number drops significantly to 19% after 3 years old, suggesting that older persons are less likely to ever outgrow a food sensitivity (Bock, 1982).

Check out what the science shows about the association between delayed food allergies and chronic ailments

Return to Natural Health Articles by Topic from Intolerance to Food: The Basics

Go to the Science of Natural Health Homepage from Intolerance to Food: The Basics