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Dietitian Dish: Food Allergies (September 2021)

Hey Mountaineer Family!

I hope everyone is settling into the semester and finding a routine that works for them!

This month, I’d like to discuss allergies, but not the seasonal kind that might be around the corner as we enter fall! I’m talking about food allergies.

Chances are you or someone you know has been diagnosed with food allergies (because they are one of the most prevalent nutrition-related conditions in the country!). Did you know that food allergies affect 3%-8% of children and 1%-3% of adults (that might not seem like a lot but that is up to 7,800,000 million people in the U.S. alone)?

Despite allergies being so common in our current day, there can be a lot of confusion surrounding this topic. So, with that in mind, let’s clear up some of that confusion as well as provide additional information related to intolerances and sensitivities.

What Is a Food Allergy?

To start things off, I think it would be helpful to properly define what a food allergy is. According to Boyce and colleagues, “a food allergy is defined as an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food.” 2

OK. That was a mouthful! In other words, a person is said to have a food allergy if the consumption of a certain food results in the immune system causing a negative health reaction.

For example, in normal protein digestion, proteins are broken down into smaller units called peptides, and those units are broken down even further into amino acids. Amino acids are absorbed by the body and enter the bloodstream.

Some people cannot completely break down specific proteins, and as a result, a peptide enters the bloodstream instead of an amino acid. The body recognizes these larger peptides in the blood as “intruders” and the immune system responds negatively. 3

The most common signs of a food allergy are tingling in the mouth, hives, itching or eczema, swelling of the lips, face, tongue and throat or other body parts, wheezing, nasal congestion or trouble breathing, abdominal pain, diarrhea, nausea or vomiting, and dizziness, lightheadedness or fainting. 3

Obviously, some very serious concerns! In more severe cases, anaphylaxis can occur. This is of major concern because this condition can be fatal if not timely treated.

Anaphylaxis is a rapid, whole-body immune response to the presence of an allergen. If you or someone you know consumes a food that causes anaphylaxis due to a food allergy, the immune system will release chemicals that signals your body to go into shock.

Anaphylaxis can cause a variety of symptoms including sudden drop in blood pressure, rapid pulse, dizziness and narrowing of the throat. Luckily, there is medication that can stop the progression of anaphylaxis called epinephrine. This medication needs to be administered immediately and followed up with being treated at an emergency. If anaphylaxis isn’t treated quickly, it could be fatal.

Allergy Versus Intolerance

It is important to note not all adverse reactions to foods are the cause of allergies

Intolerances are an adverse reaction to food, but they differ from allergies in that they do not invoke an immune response, but a digestive one. 3 You may have heard of lactose intolerance, and that people with lactose intolerance need to avoid dairy products.

If someone with lactose intolerance consumes dairy products, they may get sick and have symptoms such as abdominal cramping, bloating, flatulence and diarrhea. 3 Although consumption of dairy products can make someone with a dairy intolerance sick to a varying degree, it cannot cause anaphylaxis because there is not an immune response.

So, if lactose intolerance is not an allergy, why does it cause adverse health reactions? Let’s take a closer look.

Lactose is a natural sugar found in dairy products. Lactose is known as a disaccharide, which is a fancy name for two (di) sugars (saccharide). In order for our bodies to digest lactose, we need a special enzyme to break the disaccharide down into a smaller unit (i.e., what happens during digestion), otherwise known as a monosaccharide (this means two simple sugars in their most basic forms).

The enzyme that breaks lactose down is called lactase. In the case of lactose intolerance, the symptoms are a result of not enough lactase being present during digestion (hence why intolerances are a digestive issue not an immune one!). This forces undigested lactose to enter the large intestine where fermentation begins (this is a process where bacteria begin to chemically break down the substance), which can cause some unpleasant symptoms.

Simply put, lactose intolerance is a deficiency in the lactase enzyme. And even though it causes an adverse health reaction, it is not considered an allergy because the immune system is not involved in the digestion process.

Most Common Allergies

Now that we have an idea of the differences between an allergy and an intolerance, let’s take a look at some common allergies.

Did you know that milk, eggs, wheat, soy, shellfish, peanuts, tree nuts and gluten account for 90% of all allergies? These are known as “the big eight” food allergens because they represent the vast majority of reported cases.

If you or a friend has a food allergy, chances are it is to one of these foods. Interestingly, the prevalence of food allergies is on the rise, too.

In the U.S., hospital visits for food allergies have increased significantly from 1997-2007. 5 There are several theories as to why this is the case. Intriguing am I right?!

Some say it's merely due to an increased awareness of food allergies, which leads to seeking testing and subsequently receiving a food allergy diagnosis. Another hypothesis for the rising food allergies points to the possibility that food allergies are misdiagnosed and are actually food intolerances. 5

Other more elaborate theories include the “hygiene hypothesis,” which proclaims our Western lifestyle of cleanliness, hygiene, and antibiotic use as the culprit for a weakened immune system. This theory points to germ and infection exposure early in life as a necessity for the immune system to recognize foreign material in the body. 6

Additionally, another theory postulates that changes in our food supply, such as addition of additives, coloring and chemicals, could be the culprit of increased allergies as well. 6

Are Take Home Allergy and Sensitivity Tests Reliable?

With increased awareness of food allergies and intolerances, many people are wondering if they could have one of these conditions.

Have you ever wondered if you had a food allergy or intolerance? Well, you aren’t alone! Businesses have identified a potential to profit from this curiosity and at times, concern and have developed over-the-counter test kits for “food sensitivities.”

But do these test kits actually work and what is a food sensitivity? Defining food sensitivities is a difficult task because this term isn’t an official medical diagnosis. 7

Instead, this term is often used by the makers of over-the-counter blood tests that claim to test for these “sensitivities” without supporting claims through evidenced-based research. 7 In short, food sensitivity is a term that can be used to mean almost anything, and it doesn’t have a standard medical definition (shocking right!?) 7

According to Stukus (2018), “there are no validated tests to diagnose food sensitivity.” 8 The only way to diagnose food sensitivities is to complete a detailed dietary history, eliminate suspected foods to see if symptoms improve, then reintroduce the foods to see if symptoms return (caution! This should be done with the guidance of a medical professional) 8.

So, why question the take home, food sensitivity kit? These take-home tests for “food sensitivities” are making claims that have no supporting evidence. These tests measure levels of IgG antibodies after exposure to a specific protein and give their own interpretation as to what the levels mean. 8

We know that food allergies are caused by the IgE antibody, but NOT the IgG that these “food sensitivity” tests measure. IgG fluctuations are normal following ingestion and digestion of foods, with higher levels likely meaning that specific foods are eating often (meaning that food is a stable in your diet). It doesn’t mean that there is an adverse reaction happening! 8

To make matters worse, “food sensitivity” test kits also are known for making far reaching (and at times false!) claims connecting these “sensitivities” to poor sleep and extreme fatigue. 8

While food intolerances and potential sensitivities can impact other bodily functions, it is important to become critical consumers of information such as this because following such advice without supporting research can be harmful to your health.

Eliminating food from your diet also means eliminating all the nutrients in that food! For instance, let's say someone takes one of these food sensitivity “tests” and it is recommended that dairy products are eliminated from the diet (dairy products being a great source of calcium and vitamin D). If this individual is not aware of this guidance and they don’t increase their intake of dark leafy greens, fortified cereals or enriched calcium and Vitamin D products, they could become deficient in these micronutrients.

Side effects of calcium and Vitamin D deficiencies include increase in depressive symptoms, muscle cramps, fatigue, decreased performance, rickets, cognitive impairment and osteoporosis just to name a few!

The takeaway here is that the unnecessary elimination of foods can have serious consequences. What’s the bottom line? If you would like more information related to food allergies and intolerances and would like to undergo testing for these conditions, consultation with your doctor and/or registered dietitian is key! Until next time!

Allergen Friendly Meals at WVU: Don’t forget that WVU offers safe allergy friendly meal options in all of our dining hall locations. These meal offerings are called Simple Servings and are free of the eight most common food allergens. If you are interested in learning more about allergen safe foods on campus, be sure to reach out to me for more information!


  1. Valenta, R., Hochwallner, H., Linhart, B., & Pahr, S. (2015). Food allergies: The basics. Gastroenterology, 148(6).
  2. Boyce, J. A., Assa'ad, A., Burks, A. W., Jones, S. M., Sampson, H. A., Woods, R. A., Plaut, M., Cooper, S. F., & Fenton, M. J. (2010). Guidelines for the diagnosis and management of food allergy in the United States: Report of the NIAID-Sponsored expert panel. Journal of Allergy and Clinical Immunology, 126(6).
  3. McGuire, M., & Beerman, K. A. (2011). Chapter 4: Carbohydrates; Chapter 5: Proteins. In Nutritional sciences: From fundamentals to Food (3rd ed., pp.131-132 & 178–179). Thomson/Wadsworth.
  4. Simple servings. Sodexo USA. (n.d.).
  5. Branum, A. M., & Lukacs, S. L. (2009). Food allergy among children in the United States. PEDIATRICS, 124(6), 1549–1555.
  6. Robertson, Sally. (2019, November 20). What's Driving the Recent Rise in Food Allergies?. News-Medical. Retrieved on September 09, 2021 from
  7. Gordon, C. B. (2019, August 20). Are food sensitivity tests accurate? EatRight. Retrieved September 9, 2021, from
  8. Stukus, D. (2018, July 19). Food sensitivity tests: The pitfalls of home testing kits. Nationwide Children's Hospital.