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.

 

Highlights from Dr. Jones’ Talk, Part 2

Last week, I wrote about some of the food allergy topics Dr. Douglas Jones covered at our July UFAN chapter meeting. This week, as promised, I’m sharing more.

FAHF-2 research: FAHF-2 is the Chinese herbal compound that is being studied to see if it really helps prevent anaphylactic reactions to peanuts. While the compound has shown remarkable success with mice, it’s only in Phase 1 of clinical trials with humans. So while we are all keeping our fingers crossed, it will be several years before we’ll have scientific evidence that it works as well in humans as it does in mice. (Several drugs for other diseases have been successful in mice, only to prove ineffective in humans, so it really is too early to tell.) Phase 1 gathers safety data only (does this compound harm the human body?) and doesn’t test whether the compound is actually doing what it’s supposed to do. Phase 2 will measure doses and their effect on the body (more safety studies). Phase 3 will finally address the drug’s actual effectiveness against allergies in a limited group of test subjects. Phase 4 will expand to include a much larger group of test subjects, and Dr. Jones hopes to be a part of that phase, should the compound make it that far.

Probiotics: At this point, studies seem to show that probiotics don’t perform any better than a placebo in preventing food allergies. They may help eczema acutely, but there is no lasting effect beyond a month. There is data that shows giving probiotics to a woman a month before delivery and to the newborn for the first six months of life helps reduce food allergy, but ONLY if the child was delivered via C-section. If it is a vaginal delivery, then probiotics do not seem to be any better than placebo. So at this point, Dr. Jones feels like probiotics are safe, they probably won’t hurt anything, but they probably won’t accomplish anything either. More testing is needed.

Blood Serum (IgE) Testing: Formerly known as RAST, these blood serum tests measure the level of IgE antibodies in the bloodstream. In general, higher numbers indicate the likelihood that the person will react to an allergen. But interpreting the numbers on a blood serum test becomes tricky because there are three different companies that build the testing machines, and a recent study showed that the numbers produced by the three different machines can be very inconsistent. So comparing numbers from the other two machines is a bit like comparing apples to oranges. Most studies for food allergy have been done on an ImmunoCAP® machine and those are the numbers that should be used in determining when a food is to be reintroduced by food challenge or not. In Utah, Quest Diagnostics is the only lab that uses the ImmunoCAP® machine, and they accept all insurances except IHC. Most doctors aren’t aware of which labs use which machines. So don’t try to compare your blood serum numbers to your neighbor’s numbers. It’s probably better to use the results as broad guidelines, not as a firm indication of whether it is appropriate to do a food challenge on the child. Food challenges should only be done by an allergist in their office.

Once again, I can’t thank Dr. Jones enough for coming to share his knowledge with all of us. If you want to contact his office for an appointment, here’s his information:

Dr. Douglas H. Jones, MD
Rocky Mountain Allergy, Asthma, Immunology
1660 W. Antelope Dr ., Suite 310
Layton , UT 84041
801-775-9800
www.RockyMountainAllergy.com