Food allergies are extremely common. In fact, they affect around 6% of adults and 8% of children — and these percentages are rising. One study suggests that nearly 11% of adults in the United States have a food allergy. Although it’s possible for any food to cause an allergy, most food allergies are caused by just eight foods. According to the Food and Drug Administration (FDA), these 8 foods cause 90% of food allergic reactions in the United States.
A food allergy is a condition in which certain foods trigger an abnormal immune response. It’s caused by your immune system wrongly recognizing some of the proteins in a food as harmful. Your body then launches a range of protective measures, including releasing chemicals like histamine, which causes inflammation. For people who have a food allergy, even exposure to very small amounts of the problem food can cause an allergic reaction.
Symptoms can occur anywhere from a few minutes after exposure to a few hours or even a few days later, depending on the type of allergy. They may include some of the following:
- swelling of the tongue, mouth, or face
- difficulty breathing
- low blood pressure
- vomiting
- diarrhoea
- hives
- itchy rash
In more severe cases, a food allergy can cause anaphylaxis. Symptoms, which can come on very quickly, include an itchy rash, swelling of the throat or tongue, shortness of breath, and low blood pressure. Some cases can be fatal. Many food intolerances are often mistaken for food allergies. However, food intolerances never involve the immune system. This means that while they can severely affect your quality of life, they are not life threatening.
True food allergies can be divided into two main types:
- Immunoglobulin E (IgE) mediated. In this type of food allergy, your body’s immune system makes IgE antibodies that react with certain food. Antibodies are a type of blood protein used by your immune system to recognize and fight infection. An IgE-mediated allergic reaction usually occurs within several hours of eating the food allergen and can include mild to severe symptoms, including anaphylaxis.
- Non-IgE mediated. In a non-IgE food allergy, your immune system does not make IgE antibodies, but other parts of the immune system are engaged in mounting a response against the perceived threat. A non-IgE mediated allergic reaction often involves skin or digestive symptoms, or a combination of those symptoms, including vomiting and diarrhea, and can occur up to 3 days after eating the food allergen.
Here are the eight most common food allergies.
- Cow’s milk
An allergy to cow’s milk is most often seen in babies and young children. It’s one of the most common childhood allergies, affecting 2–3% of babies and toddlers. However, around 90% of children will outgrow the condition by the time they’re 3 years old, making it much less common in adults. A cow’s milk allergy can occur in both IgE and non-IgE forms, but IgE cow milk allergies are the most common and potentially the most serious. Children or adults with an IgE allergy tend to have a reaction within 5–30 minutes of ingesting cow’s milk. They experience symptoms like swelling, rashes, hives, vomiting, and, in rare cases, anaphylaxis. A non-IgE allergy usually has more gut-based symptoms like vomiting, constipation, or diarrhoea, as well as inflammation of the gut wall. A non-IgE milk allergy can be quite difficult to diagnose. This is because sometimes the symptoms can suggest an intolerance and there is no blood test for it.
If a diagnosis of a cow’s milk allergy is made, the only treatment is to avoid cow’s milk and foods that contain it. This includes any foods or drinks that contain:
- Milk
- milk powder
- cheese
- butter
- margarine
- yogurt
- cream
- ice cream
Breastfeeding mothers of babies with an allergy may also have to remove cow’s milk and foods that contain it from their own diets. As for babies who are not breastfeeding, a healthcare professional will recommend a suitable alternative to a cow’s milk–based formula.
- Eggs
An egg allergy is the second most common cause of food allergy in children. However, 68% of children who are allergic to eggs will outgrow their allergy by the time they’re 16 years old.
Symptoms include:
- digestive distress, such as a stomach ache
- skin reactions, such as hives or a rash
- respiratory problems
- anaphylaxis (which is rare)
It’s possible to be allergic to egg whites but not the yolks, and vice versa. This is because the proteins in egg whites and egg yolks differ slightly. Yet, most of the proteins that trigger an allergy are found in egg whites, so an egg white allergy is more common. Like other allergies, the treatment for an egg allergy is an egg-free diet. However, you may not have to avoid all egg-related foods, as heating eggs can change the shape of the allergy-causing proteins. This can stop your body from seeing them as harmful, meaning they’re less likely to cause a reaction. In fact, one study found that nearly 67% of children with an egg allergy could tolerate eating muffins containing a cooked egg component.
Some studies have also shown that introducing baked goods to children with an egg allergy can shorten the time it takes for them to outgrow the condition; however, results are conflicting, and more data is needed to confirm this. The consequences of ingesting eggs when you are allergic to them can be severe. Because of this, you should check with your doctor before you reintroduce any egg-containing foods.
- Tree nuts
A tree nut allergy is an allergy to some of the nuts and seeds that come from trees. It’s a very common food allergy that’s thought to affect around 1% of the U.S. population and perhaps up to 3% of people worldwide. Some examples of tree nuts include: Brazil nuts, almonds, cashews, macadamia nuts, pistachios, pine nuts, walnuts People with a tree nut allergy will also be allergic to food products made with these nuts, such as nut butters and oils.
They are advised to avoid all types of tree nuts, even if they’re only allergic to one or two types.
This is because being allergic to one type of tree nut increases your risk of developing an allergy to other types of tree nuts. Additionally, it’s easier to avoid all nuts, rather than just one or two types. And unlike some other allergies, an allergy to tree nuts is usually a lifelong condition. Allergies can also be very severe, and tree nut allergies are responsible for around 50% of anaphylaxis-related deaths. Because of this, people with nut allergies (as well other potentially life threatening allergies) are advised to carry an epinephrine auto-injector, like EpiPen, with them at all times. An epinephrine auto-injector is a potentially life-saving device that allows those with allergies to inject themselves with a shot of adrenaline if they begin to have a severe allergic reaction. Adrenaline, also known as epinephrine, is a naturally occurring hormone that stimulates your body’s “fight or flight” response when you’re stressed.
When given as an injection to people having a severe allergic reaction, it can reverse the effects of the allergy and save the person’s life.
- Gluten
Gluten is just a general term for the protein you find in wheat, rye, barley, or triticale (a mix between wheat and rye). Specific foods containing gluten include bread, pasta, and cereal. The condition that relates most to gluten sensitivity is one you’ve probably heard of, and that’s celiac disease. Celiac disease results in symptoms that cause diarrhoea, abdominal pain, nausea, and vomiting. With celiac disease, eating gluten causes harm to your small intestine, which can lead to a hefty bill of damage to your GI tract. Research suggests that gluten can increase intestinal permeability, spark an immune response, and cause symptoms like stomach pain, joint pain, and brain fog. It’s believed that gluten can contribute toward the development of leaky gut in those with celiac disease and possibly even IBS.
- Soy
If you find yourself with symptoms like stomach pain, gas, or bloating after eating soy, then you might have a soy sensitivity. You’ll find soy in many food products, particularly plant-based foods such as edamame, tempeh, and tofu. You might also find soy in baked goods, canned soups, or salad dressings and sauces.
- Fish
Fish allergies are common, affecting up to around 7% of adults. Similar to other allergies, people often develop fish allergies during childhood. But it’s not uncommon for a fish allergy to surface later in life. Like a shellfish allergy, a fish allergy can cause a serious and potentially fatal allergic reaction. The main symptoms are vomiting and diarrhoea, but, in rare cases, anaphylaxis can also occur. This means that those who are allergic to fish are usually given an epinephrine auto-injector to carry in case they accidentally eat fish. Because the symptoms can be similar, a fish allergy is sometimes confused for a reaction to a contaminant in fish, such as bacteria, viruses, or toxins. What’s more, since shellfish and fish with fins don’t carry the same proteins, people who are allergic to shellfish may not be allergic to fish. However, many people with a fish allergy are allergic to one or more types of fish.
- Coffee
For a lot of people, coffee runs amuck with their bowels. Natural chemicals found in coffee, like salicylates, can cause GI issues like stomach pain or abdominal cramps. You may also feel jittery, anxious, or irritable if you have a coffee intolerance.
- Wine
Roughly 10% of the population has a hypersensitivity to alcoholic beverages. Wine specifically packs a host of different allergens, such as yeast and grapes. Symptoms of wine intolerance include nasal congestion, headache, nausea, flushing of the face, and hives.
An elimination diet is a method a lot of people use for managing common food sensitivities. You do exactly what the diet says—eliminate the foods causing you problems, then you slowly reintroduce them one by one while monitoring how your body reacts. Elimination diets are great for keeping track of your symptoms and determining exactly which foods give you issues.
