Imagine enjoying a favorite dish you’ve loved for decades, only to notice your body reacting unexpectedly after taking a few bites. This is a scenario that more adults are experiencing — but can you really develop food allergies later in life?
The answer is yes, it’s possible. In fact, adult-onset food allergies are becoming increasingly more common. While they can feel unsettling at first, understanding why food allergies emerge in adulthood and how they differ from other food-related reactions is an important first step toward managing them effectively.
How does a food allergy develop?
A food allergy occurs when the immune system mistakenly treats a harmless food protein (known as an “allergen”) as a threat. In response, the body produces immunoglobulin E (IgE) antibodies. These antibodies attach to immune cells, and when the same food is eaten again, the cells release chemicals that cause an allergic reaction.
Symptoms can vary widely in terms of intensity and area of the body most affected:
- Skin: hives, itching, eczema, or flushed skin
- Mouth/throat: Itching; swelling of the lips, tongue, or throat; or hoarse voice
- Gastrointestinal: abdominal pain, cramping, nausea, vomiting, or diarrhea
- Lungs: wheezing, nasal congestion, or trouble breathing
- Anaphylaxis (entire body): wheezing, persistent cough, severe dizziness, loss of consciousness, or weak pulse
It’s helpful to distinguish food allergies from other intolerances and sensitivities. Specifically, allergies involve the immune system, while intolerances are usually linked to the digestive system. Sensitivities, on the other hand, tend to cause discomfort without triggering an immune response.
Can food allergies develop later in life?
actually develop at any age. One survey suggests that nearly half of adults with food allergies developed at least one of them later in life, and about one in four had no food allergies during childhood at all. The same study ultimately concluded that food allergies may develop in adulthood more often than seasonal allergies.
Adult-onset food allergies refer to allergic reactions that first appear after the age of 18, even to foods that were previously well-tolerated. In these cases, the immune system seems to evolve as the body ages, learning to respond defensively to foods it once accepted. Since there’s no prior history, adult-onset allergies can take anyone by surprise and are often much more noticeable (and even severe) when they first appear.
The nine most common causes of food allergies identified in the United States are as follows:
- Shellfish (such as shrimp, crab, or lobster)
- Finned fish (such as salmon, tuna, halibut, or cod)
- Wheat
- Soybeans
- Peanut
- Tree nuts (such as walnuts, almonds, cashews, or pistachios)
- Sesame
- Cow’s milk
- Eggs
Why do adults develop food allergies? 8 common causes
Research as to why food allergies can develop in adulthood remains inconclusive, but the following factors may play a role:
1. Changes in the immune system
The immune system continues to evolve throughout life. These changes at the molecular, cellular, and systemic levels can sometimes make the body more likely to develop food allergies as adults. As a result, foods that were once tolerated without issue may suddenly provoke symptoms. This gradual remodeling of the immune system (also called “immune senescence”) explains why some adult-onset food allergies can emerge even without a clear trigger.
2. Delayed or new food exposure
In some cases, adult-onset allergies appear simply because certain foods weren’t regularly consumed earlier in life. Exotic produce or regional cuisines you’ve rarely consumed in childhood may trigger reactions if the immune system misinterprets these unfamiliar proteins as harmful. Your adult palate may be more adventurous, but your immune system may not always be as forgiving.
3. Tick bites
Certain tick bites can introduce a sugar molecule called alpha-gal into the bloodstream. This can later cause allergic reactions to mammalian meat such as beef, pork, or lamb — a condition known as alpha-gal syndrome.
4. Location
Moving to a new region exposes the immune system to new pollens, grasses, and plant allergens. In some individuals, this can lead to cross-reactivity, where the immune system confuses proteins in foods with those found in environmental allergens. This phenomenon, known as oral allergy syndrome, may cause itching or discomfort in the mouth and throat after eating certain raw fruits, vegetables, or nuts.
5. Certain food triggers paired with exercise
In rare cases, food allergies only appear when eating is combined with physical activity. During intense exercise, stomach acid levels decrease, and the intestinal lining allows food proteins to enter the bloodstream more easily. If a person already has IgE antibodies to a food consumed before exercise, this can trigger a serious allergic reaction. This is known as food-dependent exercise-induced anaphylaxis.
6. Genetics
A family history of allergies, as well as closely related conditions like asthma and eczema, can increase the likelihood of developing food allergies later in life. While genetics alone doesn’t determine the outcomes, inherited tendencies may make some individuals more prone.
7. Gut health
Growing research suggests that gut health is crucial in how the immune system responds to food. The balance of bacteria in the digestive tract helps regulate immune tolerance. When this balance is disrupted by illness, antibiotics, chronic stress, or other factors, sensitivity to certain foods may increase and contribute to the development of allergies.
8. Processed diets
Modern diets that are low in fiber and high in refined sugars and processed starches may also heighten the risk of food allergies. Fiber-rich foods help support beneficial gut bacteria, which, in turn, promote immune balance. When these foods are replaced with heavily processed alternatives, the gut may become less resilient, potentially increasing the chances of allergic responses over time.
Diagnosing and treating adult-onset food allergies
So now you know that food allergies can indeed develop later in life. What’s next? If you notice symptoms that are allergy-like, start by consulting your primary care provider or an allergist for a thorough medical evaluation. Be ready to share a detailed history of what you ate, the symptoms you experienced, and how quickly they appeared to help specialists determine which foods may be responsible.
Next is diagnostic testing, which may include specific IgE blood tests to identify potential triggers. This typically comes with component testing, which helps uncover cross-reactivity. Together, these tools create a more accurate picture of your allergy risk.
Once a food allergy is confirmed, you’ll be able to manage it more effectively. This entails actively avoiding these allergens and any food that may contain their derivatives. Make it a habit to read food labels carefully when picking ingredients, ask questions about food preparation, and communicate your needs clearly when eating outside the home or traveling.
If you’re at risk of severe reactions, carrying epinephrine is an essential safety measure. Antihistamines may be recommended for milder symptoms, depending on your healthcare provider’s advice.
Consult a Health Loft dietitian to eat well, even with food allergies
Learning that you’ve developed a food allergy later in life can be unpleasant, but rest assured that, with the right guidance and precautions, it’s entirely possible to live safely and comfortably even while adjusting to new dietary needs.
Making smarter food choices, whether at home or outside, starts with awareness. Keeping a simple record of your symptoms and any patterns in your reactions can help you better understand your triggers. Being open about your allergies with family members, friends, and restaurant staff also ensures that meals are prepared with your needs in mind.
For long-term management, working with a registered dietitian or nutritionist who specializes in food allergies can do wonders. These experts develop personalized nutrition plans based on your specific allergies, helping you avoid allergens, prepare for emergencies, and maintain a varied diet you can enjoy without feeling restricted.
At Health Loft, we support adults navigating food allergies with practical tools and a compassionate care team. By partnering with a Health Loft dietitian, managing a food allergy can become a practical part of everyday life.
This article was reviewed by Adrienne DePaul, MS, RDN. It is intended for informational purposes only and does not replace personalized nutritional advice.
