Food Allergies Today: An Expert Q & A
There are many unknowns in the food allergy world today. Why are food allergies on the rise? What can I do to prevent my child from developing a food allergy? How do I find out if I have a food allergy or intolerance, or if my child has one? With the help of two of our medical advisors, Dr. Jordan Scott and Dr. John Lee, we have answered some of these common food allergy questions to help you dine with confidence! Let’s get started.
1) What is a food allergy and how does it differ from a food intolerance?
A food allergy is an immune system reaction. Your immune system is comprised of five different types of immunoglobulins/antibodies (IgA, IgD, IgE, IgG, and IgM). If you have a food allergy, IgE is the responsive antibody. When exposed to a food allergen, IgE attaches to the allergen, mistaking it as a foreign intruder. This IgE-allergen compound then binds to immune cells, triggering a release of histamine and other chemicals that produce an allergic reaction. Symptoms can affect the central nervous, respiratory, and gastrointestinal systems, and produce epidermal symptoms such as hives, rashes, or eczema. In the most extreme cases, a food-allergic reaction produces anaphylaxis, a life-threatening response that requires immediate medical treatment.
Food intolerances often affect gastrointestinal function, but they can also impact the central nervous system, respiratory health, and skin. The main difference between a food allergy and intolerance is that, although intolerance symptoms can be severe, they are not life threatening and will not produce anaphylaxis.
2) What are the leading theories for the significant increase in food allergies?
Between 1997 and 2011, food allergies among children increased approximately 50 percent, according to the CDC. Unfortunately, there is no clear answer as to why. Below are some of the leading theories, in no particular order.
Theory One: Changes in our food system
Over the past few decades, our agricultural system has undergone a considerable transformation, including the introduction of GMOs (genetically modified organisms), increased pesticide application, and the addition of numerous chemicals to our foods. This theory suggests that these chemicals and modified foods are affecting our bodies and immune systems, particularly our gut health, thereby increasing our susceptibility to food allergies and intolerances.
Theory Two: Hygiene hypothesis
The second theory is the “hygiene hypothesis,” suggesting that our modern world is too clean, and our reduced exposure to bacteria is weakening our immune systems. Some research also suggests that the overuse of antibiotics in animals and the rise of prescription medication is killing the good bacteria in our gut alongside the bad.
Theory Three: Epigenetics
Some research indicates epigenetics are responsible for the rapid increase in food allergies—heritable changes in gene expression that don’t change the underlying DNA sequence. Epigenetic changes can be the product of environmental or other external factors, like diet or smoking, or the result of natural occurrence. Research is continuing to uncover the role of epigenetics in a variety of human disorders and fatal diseases.
Theory Four: Delayed allergen exposure
In the past few years, a growing body of research is suggesting that we may not be introducing children early enough to common allergens. In February 2015, the LEAP Study results came out, debunking the previously accepted practice of discouraging exposure to peanut among high-risk infants. This misguided approach may have contributed to the rise of peanut allergies and other food allergies.
3) What are the current methods for diagnosing a food allergy? How have they changed in the past several years?
To diagnose a food allergy, an allergist performs one of two tests (or both): a blood test (such as an ImmunoCAP test) and/or a skin prick test. The blood test measures the level of allergen-specific IgE antibodies present in the blood. Skin prick tests are exactly as they sound: the allergists pricks the patient’s arm or back with a sterile small probe containing a tiny amount of the food allergen. A food allergy diagnosis is confirmed if a wheal (a raised white bump surrounded by a small circle of red irritated skin) develops around the contact area.
In some cases, an allergist may suggest a food elimination diet to pinpoint the offending food. They may also recommend an oral food challenge.
In an oral food challenge, an allergist administers tiny amounts of the potential allergen in gradually increasing doses over a set period of time (usually 1-3 hours). The patient is closely monitored in the event the food produces an allergic reaction, and epinephrine is always on hand in case of a reaction.
To date, oral food challenges are considered the gold standard for food allergy diagnosis. Skin prick and blood tests aid in diagnosis, but they are prone to error—false positives are not uncommon. For this reason, many allergists avoid blanket food allergy screening, and carefully choose which foods to test. Skin prick tests and blood tests have been standard practice for aiding in allergy diagnosis for the past two decades.
4) What are some common allergic reaction symptoms?
It’s first important to note that no two allergic reactions are the same, and just because you have a mild reaction to a small bit of sesame one day, doesn’t mean symptoms will present in the same way the next time you ingest that same small amount. Below are the most common symptoms to an allergic reaction.
Mild symptoms include: itchy or runny nose, sneezing, itchy mouth, a few hives or mild itch, and mild nausea or discomfort.
Severe symptoms include: shortness of breath, wheezing, repetitive cough, pale or bluish skin, faintness, weak pulse, dizziness, tight or hoarse throat, trouble breathing or swallowing, significant swelling of the tongue or lips, hives or widespread redness, repetitive vomiting or severe diarrhea, anxiety or confusion, or some combination thereof.
It’s important that food-allergic individuals also be aware of biphasic anaphylaxis. A biphasic allergic reaction is a second episode of anaphylaxes that typically occurs within the first several hours after the initial anaphylactic event. The symptoms of biphasic anaphylaxis can be more severe than the initial reaction. Due to the risk of biphasic anaphylaxis, a doctor may require that you remain in the hospital for several hours after an anaphylactic event for monitoring.
5) What are the most common misconceptions about food allergies?
There are several misconceptions about food allergies. Below are a few that we hear most frequently:
Food allergies aren’t real—False. Food allergies are real. They are a response to the body’s immune system upon exposure to an allergen. The immune system misinterprets the food as a harmful invader and releases histamine and other chemicals to protect the body from perceived harm.
Food allergies aren’t life threatening—False. If an allergic reaction becomes severe, it can lead to anaphylaxis—a potentially fatal allergic reaction that involves the rapid onset of swelling which can obstruct air passageways. Symptoms of an allergic reaction may be isolated to one major system in the body (e.g., wheezing or difficulty breathing), or can involve multiple systems (e.g., lungs, heart, throat, mouth, skin, or gut), and typically present within minutes after a person ingests the offending food.
Each allergic reaction becomes increasingly worse—Not necessarily. Allergic reactions can be unpredictable. The severity of a reaction is based on a number of factors, including: the amount of the allergenic food ingested, the person’s degree of sensitivity to that food, if exercise is involved, if they are sick, if alcohol is present in their body, and if certain medications are being used (for example, NSAIDS may increase the severity of a reaction). A person with food allergies might not always experience the same symptoms each time.
A food can be made less allergenic by cooking it—Partially true. Because a food allergy is an immune system response to a protein in a food, the protein remains in the food during heating, so it cannot be cooked out. The exception to this rule is sometimes seen in highly processed foods, and with milk and egg allergies—some people are able to consume these foods after heating, such as baked goods. Ask your allergist before trying this at home.
Adults don’t develop food allergies—False. Though most food allergies start in childhood, they can develop at any age.
Peanuts are the only food that cause severe reactions—False. While peanuts are the leading trigger of food-related anaphylaxis, any food can elicit a severe reaction—other common foods include seafood, milk, wheat, eggs, and sesame seeds.
One small bite is ok—If someone has a severe food allergy, and is highly sensitive to small amounts, even a tiny bite can trigger anaphylaxis. It is well documented that allergic individuals can experience severe reactions to trace amounts of an allergen in their food.
6) What are the three most important things a food-allergic individual can communicate to their friends, family, and co-workers?
First, alert your “tribe” (friends, family, work colleagues, caregivers) of your food allergies and their accompanying health risk. Also note the various ways you can be exposed (e.g., ingestion, touch, and inhalation).
Second, let them know what symptoms to watch for in case of a reaction.
Finally, tell them where you keep your emergency medications and teach them how to use an epinephrine auto-injector. Share your doctor-provided food allergy action plan, if you have one. Often parents with food-allergic children have one to serve as a guide for caregivers. The American Academy of Pediatrics recently published a customizable Allergy and Anaphylaxis Emergency Plan.
7) What role do you see technology playing in the lives of individuals with food allergies and how they manage them now, and in future?
Food allergies have increased at an alarming rate over the past two decades. The silver lining is that we’re putting more research dollars and efforts into allergy education, management, and prevention. Numerous start-ups are spearheading this effort with cutting-edge technologies and innovation. This Spokin article published in January highlights several. Until we find a cure, technology is going to become a necessary part of how we manage food allergies.
8) What will be important for future food allergy diagnoses and treatment?
With food allergy diagnoses at an all-time high, it will become increasingly important to have improved diagnostic tools available to better understand who is at risk for severe reactions. New therapies to help people better manage their allergies are being developed every day. One example is oral immunotherapy, or OIT. OIT is a method of food desensitization that involves re-introducing the immune system to the allergenic food via oral ingestion in gradually increasing amounts over time, with the goal of eventual tolerance. Another example is the Viaskin® patch, otherwise known as the peanut patch. This approach uses epicutaneous immunotherapy. After applying the patch to your skin, the allergen is concentrated in the top layers of the skin, where it activates the immune system by targeting antigen-presenting cells without passage of the antigen into the bloodstream. The peanut patch recently entered Phase III clinical trials. Products are also currently being developed for milk and egg.
Is desensitization the future of food allergies? Or is a cure on the horizon? Only time will tell. Until then, innovation, research, heightened awareness, and education are paving the way for a brighter food allergy future.
If you have additional questions you’d like our experts to answer, please send them to Meg at firstname.lastname@example.org. We’d love to hear from you!
- The Allergy Amulet Team
These questions, and their corresponding responses, were written by the Allergy Amulet team and reviewed by Allergy Amulet advisors, Dr. Jordan Scott and Dr. John Lee.
Dr. Scott is an allergist/immunologist and operates several private allergy clinics throughout the Boston area. He is on the board of overseers at Boston Children’s Hospital, and the past president of the Massachusetts Allergy and Asthma Society. Dr. Scott is an allergy/immunology instructor at the University of Massachusetts.
Dr. Lee is the clinical director of the food allergy program at Boston Children’s Hospital. Dr. Lee is widely recognized for his work in food allergy, and his commitment to patient health.