The Connection between Food Allergies and the Immune System Response

by Kelley Lindberg


This week, I'm happy to host guest blogger Valerie Johnston, a health and fitness writer for Healthline.com. Her article examines the immune system's role in food allergy reactions, as well as the difference between a food intolerance and a true food allergy. Thanks, Valerie!

People who are genetically predisposed to have food allergies will not experience an allergic reaction until they are exposed to the food they are allergic to. In other words, the tendency to develop food allergies is already inherent, and the allergies then develop upon exposure to the allergen.

The body of a person who is genetically predisposed to allergies will produce a type of protein called immunoglobulin E (IgE) after being exposed to the specific food that they are allergic to. When the food is consumed, the body’s immune system is triggered to produce specific types of IgE in larger quantities than normal. After IgE is released, it attaches to the mast cells of the body. Your body’s mast cells occur in all of the tissues of the body, but are more commonly found in areas of the body that are associated with allergic reactions, including the skin, gastrointestinal tract, throat, and lungs.

In most cases, a person with food allergies will not experience symptoms until the second time they are exposed to the food allergen. This is because, after the IgE attaches to the body’s mast cells after the first exposure to a food allergen, they are now prepared to combat any foods that the body is allergic to the second time the food is consumed. When the allergen is consumed, the IgE on the mast cells triggers the release of chemicals known as histamines. It is these chemicals that cause a variety of food allergy symptoms.

For example, many people with food allergies have difficulty swallowing or breathing when they consume the foods they are allergic to. This is because the mast cells in the throat and mouth release histamine, which produces these symptoms. Histamine can be released wherever mast cells are located, including the throat, ears, nose, and gastrointestinal tract.

Food Allergy Vs. Food Intolerance

Most people who have food sensitivities (food intolerances) will say that they have a food allergy. It is very important to distinguish between these two problems, since food allergies can have life-threatening consequences and are related to the body’s immune system response.

As described above, a food allergy is a response to a food allergen by your immune system. In most cases, the body is responding to a specific protein in a type of food. Histamine antibodies are produced to fight against a specific protein that the body mistakes as harmful. Common food allergies include, but are not limited to, dairy, peanuts, tree nuts, shellfish, wheat, and soy products.

Symptoms of food allergies include:

• Nausea
• Hives or a rash
• Itchy skin
• Abdominal pain
• Chest pain
• Difficulty swallowing or breathing
• Anaphylaxis

Food intolerance is not an immune system response. Instead, a food tolerance is a response made by the digestive system. Some people have difficulty digesting certain types of foods, such as lactose (dairy intolerance).

Symptoms of food intolerances include:

• Nausea
• Vomiting
• Bloating, cramps, or gas
• Heartburn
• Headaches
• Diarrhea
• Constipation
• Irritability

While a person with a food allergy and a person with a food intolerance may share a few similar symptoms, the symptoms of a food allergy are usually a lot more severe and can even lead to death if the condition is not diagnosed properly. A proper diagnosis from your doctor or allergy specialist will allow you to prevent symptoms whether you have an allergy or intolerance to certain types of food.

Valerie Johnston is a health and fitness writer located in East Texas. With ambitions of one day running a marathon, writing for Healthline.com ensures she keeps up-to-date on all of the latest health and fitness news.

 

Food Allergy Skepticism

I’m practicing wearing contact lenses today. I gotta say… yuck. I don’t like ‘em. This is my fourth day wearing them, and they are irritating. Literally. My eyeballs feel sticky and gummy and cold. Yeah, cold. I don’t get why, but they do.

You’ll never guess what my first thought was.

OK, you did guess: “I wonder if I’m allergic to the solution?”

I wonder why we’re so quick to assign the word “allergy” to anything that makes our body feel funny.

I don’t know if I’m allergic to my contacts. I’m going back to the eye doctor in a couple of days to find out his best explanation. In the meantime, I’m still wearing them for a couple of hours each day so I can make sure it’s not just a “getting used to them” sort of problem. Maybe I’m just being whiney. (Hard to believe, but my husband might suggest it’s a possibility.) But it’s really, really tempting to assume I’m allergic right off the bat, with no data to support it.

Have you ever encountered someone who doesn’t believe you when you describe how serious a food allergy is?

Silly question. Of course you have. We all have.

I can’t figure out why some people don’t believe me. Do I look like the kind of person who would walk up to you and say, “Hey, let me tell you a big, fat lie”?

Maybe part of the problem is that too many people have used the word “allergy” in so many ways for so many reasons for so long, that the word no longer has any impact.

How many people have you heard say they were allergic to cigarette smoke, when really they just hate it and don’t want to be around it? (I admit it. I used that excuse in my teen years, thinking I was being clever and creative. Surely it would have been easier to just say, “I don’t like it,” but that’s teenage logic for you.)

And a huge percentage of folks have pet allergies or common hay fever, which is an allergic reaction to pollens. In most of these people, pollen allergies cause discomfort (or misery) in the form of watery eyes, sneezing, sinus pain, itchiness, etc. But for the majority of sufferers, pollen allergies aren’t usually a life-threatening disease and don’t usually cause anaphylactic reactions. (There are always exceptions, unfortunately.)

So when people hear “food allergy,” they tend to think, “So you sneeze a little. For Pete’s sake, take some Benedryl and get over yourself.” Because most of their experience with allergies up to this point has been either imagined annoyances or the real -- but mostly non-fatal -- hay fever or pet allergies.

And then there’s the confusion with food intolerances. Lactose intolerance is a well-known disease now, thanks in large part to all the commercials for drugs that treat it. But now non-sufferers often think a milk allergy is just lactose intolerance. They don’t understand why we’re so freaked out about whey in the ingredients list of a cracker. “Why can’t you just take a pill?” they ask, annoyed, clueless that a food intolerance is a completely different disease than a food allergy.

So they, and I, and probably you, have developed a healthy skepticism for the word “allergy.”

I don’t know what to do about it, though, short of coining a new word for life-threatening food allergies, or using the adjective “life-threatening” in front of the word “allergy” in all my conversations. (I don’t know about you, but I don’t like using that term on a frequent basis in front of my impressionable 8-year-old.)

I guess I’m resigned to having to explain patiently to the uninitiated, over and over. A little education goes a long way.

I’m also vowing to be careful how I use the word “allergy.” So when I go see the eye doctor, I’m not going to say the word. I’m going to describe the symptoms, and let him suggest possible cures. And if he says “allergy,” I’m going to ask how he knows. Maybe there’s a test to prove it.

How do you handle people who don’t believe how serious a food allergy is? Do you have any ways of explaining that seem to get through, without creating a new enemy? Let us know your tips!