
Food reactions
Food allergy, intolerance, and sensitivity testing and treatment.
Looking to identify and address your food allergies, intolerances, and sensitivities? This page has the answers you need.
Understanding your food reactions
Food allergy, intolerance, and sensitivity.
Our digestive and immune systems are always on the lookout for potential threats that enter the body. With every bite, our immune system evaluates the safety of our food, and any allergies, intolerances, or sensitivities we experience reflect the immune system detecting a food as a danger. The way the immune system responds to a substance can be as unique as we are, shifting over time to become more or less sensitive to certain foods.
Food reactions testing
Food allergy testing and treatment.
Our functional medicine food allergy expert uses state-of-the-art testing, alongside tracking your symptoms and food diary, to pinpoint the specific foods you’re reacting to. Through a comprehensive assessment, she’ll determine if your reactions are due to an allergy, intolerance, or sensitivity.
From there, she’ll work to address any underlying factors that may be causing the food reactions. Our goal is to help you gradually increase your tolerance and ability to enjoy a wider variety of foods over time.

What is the difference between food allergies, intolerances and sensitivities?
Food allergies typically fall into two main categories.
Immediate hypersensitivity reactions (allergies).
A true food allergy involves an immune reaction triggered by IgE antibodies. These reactions develop rapidly, within minutes to an hour of ingesting the allergen. The immune system responds by activating mast cells, causing them to release histamine. This triggers a chain reaction, with more mast cells breaking open and releasing more histamine. The result is symptoms like hives, coughing, sneezing, watery eyes, or even anaphylaxis – a life-threatening reaction requiring an EpiPen and emergency medical care. Susceptibility to food allergies often runs in families.
Symptoms of an allergic reaction can appear anywhere on the body, ranging from mild irritation to severe, life-threatening anaphylaxis. Anaphylaxis is a dangerous type of allergic reaction where the throat swells, restricting breathing, blood pressure plummets, and the person goes into shock, which can be fatal.
While almost any substance can trigger an allergic response, the most common food allergens include:
- Peanuts
- Tree nuts
- Dairy
- Fish, shellfish, and seafood
- Soy
- Eggs
Delayed hypersensitivity reactions (food sensitivities).
These non-IgE mediated food sensitivities are also known as “food reactions.” They can be tricky to identify because symptoms may not appear for 1.5 to 72 hours after eating the trigger food. Unlike true food allergies, these reactions involve the production of IgG antibodies and inflammatory compounds, but they are not life-threatening.
One example of this type of delayed food reaction is non-celiac gluten sensitivity (NCGS). In this case, the body reacts to gluten, but it’s not a true wheat allergy.
Food intolerances.
Many people experience uncomfortable digestive symptoms after eating certain foods or substances, a condition known as food intolerance. Unlike food allergies, food intolerances do not involve the immune system. Instead, they are often caused by a lack of the enzymes or chemicals needed to properly break down the offending food. A prime example is lactose intolerance.
Food intolerances are actually much more prevalent than food allergies. The symptoms are typically gastrointestinal in nature and tend to appear gradually, rather than immediately, after consuming the problematic food.
Symptoms of food allergies, intolerances and sensitivities.
Food allergy symptoms.
Food allergy symptoms can change throughout a person’s life, from no reaction to severe reaction. Some people never grow out of childhood allergies and some gather allergies as they age. Two people with the same allergy can have very different reactions, in both the symptoms and the severity.
Symptoms of allergic reactions may include:
Skin symptoms.
- Hives/Urticaria: This itchy, raised, red rash can sometimes form tiny blisters.
- Angioedema: Look out for redness and swelling, often around the face, eyes, lips, and mouth/throat.
- Eczema/Atopic Dermatitis
- Psoriasis
Respiratory symptoms.
- Sneezing
- Trouble breathing
- Asthma
Digestive symptoms.
- Diarrhea
- Nausea
- Vomiting
- Excessive, smelly flatulence
- Colic
- Abdominal pain
- Constipation (less common)
Other symptoms.
- Runny nose
- Rhinitis (nasal inflammation)
- Sinusitis (sinus inflammation)
- Fatigue
- Watery/itchy eyes
- Conjunctivitis (eye inflammation)
- Headaches
- Swelling of the larynx and throat
- Anaphylactic shock/anaphylaxis (severe allergic reaction)
- Low blood pressure
- Loss of consciousness
- Cardiac symptoms like rapid or reduced heart rate
- Mood and behavioral changes
If you have a food allergy, you’ll likely notice symptoms right away or within just a few hours after eating the triggering food.
Food sensitivity symptoms.
Symptoms of food sensitivities can be similar to allergies and may include:
- Skin rashes like hives and eczema
- Fatigue
- Brain fog and mood changes
- Digestive issues
- Achy joints
- Pain
- General weakness
These symptoms often appear within 72 hours after eating the problematic food. The delayed reaction is a key difference from food allergies.
Although food sensitivity symptoms may not be immediately life-threatening, they can still be quite severe. These symptoms can lead to serious complications like nutritional deficiencies and gut flora imbalances. What’s more, undiagnosed and untreated food sensitivities have been connected to the development of autoimmune disorders. Ultimately, food sensitivities can have a major impact on your overall quality of life and ability to enjoy eating.
Food intolerance symptoms.
Food intolerance can trigger a range of unpleasant digestive symptoms, including:
- Diarrhea, which may vary from loose stools to explosive, watery episodes that are often smelly, frothy, or contain mucus
- Constipation
- Nausea and vomiting
- Excessive gas and bloating
- Abdominal pain
- Colic
Unlike food allergies, food intolerance symptoms are most commonly digestive in nature, rather than involving the full-body allergic reactions seen with allergies. The symptoms can be uncomfortable but are not usually life-threatening.
Other symptoms you may experience include:
- Difficulty breathing, wheezing, and shortness of breath
- Asthma
- Headaches or migraines
- Brain fog
- Eczema and hives
- Joint pain
- Vertigo
What causes food allergies, intolerances and sensitivities?
Many different factors can trigger the development of food sensitivities, allergies, and intolerances. These triggers can include:
- Genetic predisposition to allergies, including (but not limited to) food allergies
- Existing conditions like asthma or eczema in the family
- Seasonal hay fever
- Disruptions to gut flora, such as a reduced number of species or an overgrowth of damaging bacteria
- Intestinal hyperpermeability, sometimes called “leaky gut”
- Certain medications
- Impaired digestive secretions from the stomach or pancreas
- Slow food transit time through the digestive system
- Changes in mucus production
- IgA antibody deficiency
- A tick bite that triggers an allergy to the alpha-gal protein found in red meat and animal products
- Frequently eaten foods
- Skin exposure, especially to a repeated substance on broken or damaged skin
- Workplace exposure to a substance like latex, which is common with banana allergies
Molecule triggered food intolerances.
Food intolerances can be triggered by a wide range of molecules, but some of the most common culprits include:
- Dairy – both lactose (a milk sugar) and casein (milk protein)
- Wheat
- Yeast
- Egg
- Beans (Red Kidney)
- Corn
- Barley
- Pistachio
- Tomatoes
- Eggplant
- Bananas
- FODMAPs (fructose, oligosaccharides, polyols)
- Caffeine
- MSG – monosodium glutamate
- Salicylates and amines (molecules found commonly in foods)
- Sulphites and benzoates (often used as preservatives and in drinks)
Food intolerances due to enzyme deficiency.
Food intolerances occur when the body lacks certain enzymes or molecules needed to properly break down specific foods. For example, people may lack:
- The lactase enzyme, which is required to digest lactose in dairy products
- Enzymes to break down sugars like sucrose, galactose, fructose, and pentose (these are very rare)
- The trehalase enzyme, needed to digest the sugar trehalose found in mushrooms
- The ability to properly absorb certain amino acids, leading to protein malnutrition (also very rare)
- Sufficient bile to properly digest fats
If left untreated, food intolerances can contribute to the development of autoimmune diseases, rheumatic conditions, and neurological problems like rheumatoid arthritis, lupus, multiple sclerosis, type 1 diabetes, and cerebral ataxia. Therefore, it’s essential to identify and address any food reactions to maintain long-term health.
Conventional treatment for food allergies, intolerance and sensitivity.
Your doctor will likely be concerned about an IgE-mediated food allergy. They may also need to rule out an autoimmune condition like celiac disease. Depending on the severity and type of your food sensitivity, your doctor may refer you for testing to identify your food triggers.
The common food sensitivity tests used in the United States include:
- Skin prick testing to check for IgE antibody reactions
- Blood tests
- Oral allergen challenge tests
- Patch tests
The first and most important recommendation for managing a food allergy is to completely avoid the trigger food. In addition to this permanent avoidance, your doctor may also prescribe various medications:
- Antihistamines for less severe allergies
- Intranasal corticosteroid sprays (INCS)
- Combined INCS and antihistamine sprays
- Salt water nasal sprays and rinses
If there’s any risk of anaphylaxis, your doctor will likely prescribe an adrenaline autoinjector (such as an EpiPen). In an emergency, adrenaline can rapidly reverse the life-threatening effects of anaphylaxis by reducing throat swelling, opening airways, and maintaining blood pressure and heart function.
Immunotherapy is a process of desensitization. It involves administering small, gradually increasing doses of allergens over 3 to 5 years. This may help manage certain allergies.
If a non-IgE food intolerance is identified, your doctor will likely recommend avoiding that food for life.
Some food intolerance tests can be inaccurate. This can make conventional doctors cautious when assessing evidence-based functional food sensitivity testing, which are often more reliable.
That’s why it’s important to work with experienced food allergy and food intolerance practitioners who specialize in functional medicine. They can order state-of-the-art pathology tests and provide expert interpretation to guide effective treatment.
Functional testing for food allergies, intolerance and sensitivity.
Functional medicine specialists may use a variety of tests to identify food sensitivities and related issues. These can include checking for allergies, nutrient deficiencies, intolerances, and problems with digestive function. The tests can look at the makeup and diversity of gut bacteria, inflammation levels, parasites, how quickly food moves through the digestive system, the health of the digestive lining, and sugar intolerance. Results of these comprehensive tests can help practitioners understand which other body systems may be involved and determine the best course of treatment.
The BionwoRx functional medicine approach.
Functional medicine treatment for food allergies, intolerances and sensitivities.
Functional medicine takes a personalized, holistic approach to addressing food sensitivities. Testing identifies any food allergens, intolerances, or sensitivities. The treatment plan may include:
- Eliminating trigger foods, at least short-term
- Adding specific dietary inclusions
- Restoring the mucosal lining of the digestive tract
- Improving the gut’s barrier function if intestinal hyperpermeability is present
- Reducing inflammation
- Stabilizing mast cells and modulating the immune response
- Improving gut flora diversity and composition
- Enhancing gut motility
- Ensuring proper digestion through healthy acid and gastric secretion levels
- Maintaining optimal micronutrient status
This comprehensive, personalized approach aims to address the root causes of food sensitivities for long-term health and wellness.
Functional medicine is perfectly positioned to address food sensitivities, allergies, and intolerances. This evidence-based approach uses a holistic, patient-centered framework to reduce reactivity, improve digestion, and support immune function.
Treatment may include:
- Vitamin, mineral, or other micronutrient supplements like magnesium, vitamin C, A and D, B vitamins, zinc, or N-acetyl cysteine
- Herbs to modulate and regulate immune function, such as echinacea, Albizia lebbeck, Baical skullcap, or poke root
- Herbs to improve digestive function, including slippery elm powder, meadowsweet, ginger, and gentian
- Anti-inflammatory herbs like turmeric, boswellia, garlic, fenugreek, licorice, and calendula
FAQs.
Can food allergies cause behavior problems?
Food allergies can trigger a variety of reactions, including disruptions to the body’s mood-regulating neurotransmitters. When these essential chemicals become imbalanced, it can lead to symptoms like depression, anger, anxiety, hyperactivity, and withdrawal. This is particularly noticeable in children, but it’s not limited to them.
Luckily, food allergy testing from our functional medicine specialist can help identify trigger foods and alleviate these troubling symptoms.
Are food allergies autoimmune?
Food allergies are an IgE antibody reaction, which is part of the immune system’s response, but not an autoimmune condition. In a food allergy, the body mistakenly produces antibodies against a food it has identified as dangerous, and it’s the food itself that triggers the reaction.
In contrast, autoimmune conditions occur when the body reacts against its own tissues due to misidentification. Interestingly, there is some emerging evidence that untreated food allergies may trigger autoimmune conditions in individuals who are susceptible or have a genetic predisposition.
Can food intolerances be reversed?
Food intolerances can sometimes be reversed or reduced, depending on the underlying cause and severity.
If someone is lactose intolerant because their body doesn’t produce enough lactase to break down dairy, they can take a lactase supplement, though this doesn’t permanently fix the intolerance.
However, if food sensitivities stem from gut imbalances, leaky gut, or other digestive issues, addressing those root causes may allow complete reversal of the food intolerances.
Seeing our functional medicine specialist can help identify the root cause of your food intolerances, through testing and assessment. They can then create a personalized plan to treat the issue naturally and effectively.
Are food intolerances hereditary?
Research shows a strong genetic link when it comes to allergies, including food allergies – they tend to run in families. This is also true for food sensitivities, though through a different mechanism, usually by disrupting digestive function.
The susceptibility to digestive disorders that can contribute to food sensitivities can be inherited, such as IBS or autoimmune conditions like IBD. Similarly, the likelihood of not producing sufficient enzymes for breaking down certain molecules (like the lactase enzyme for lactose in milk) is often genetically inherited, leading to food intolerances.
In summary, both food allergies and food sensitivities/intolerances have a strong hereditary component, whether it’s the immune system’s response or the body’s ability to properly digest certain foods. Genetics play a significant role in one’s predisposition to these food-related issues.
Can food sensitivities cause weight gain?
Food sensitivities can disrupt your digestion, gut health, and metabolism, leading to unwanted changes in your body weight – whether that’s gaining or losing pounds.
Determining if you have a food intolerance, sensitivity, or allergy, and identifying the root cause, can empower you to manage its effects on your weight.
The friendly food intolerance expert at BionwoRx can pinpoint the problem and guide you towards an effective treatment plan.