Food Allergy vs. Food Intolerance

Understand the key differences so you can take control of your health and make smarter choices.

Understanding Food Reactions

Do you notice bloating, fatigue, skin rashes, or headaches after eating certain foods? You’re not alone — but the reason could be very different depending on whether it’s a food allergy or a food intolerance.

The Numbers Tell the Story:

An estimated 33 million Americans live with at least one food allergy — roughly 1 in 10 adults.*
Research suggests that up to 20–25% of people experience food intolerances or sensitivities, though many go undiagnosed.*

Why the gap? Allergies involve the immune system and often trigger fast, obvious reactions. Intolerances, or sensitivities on the other hand, build more slowly and can cause a wide range of symptoms — which is why they’re often overlooked or misattributed for years.*

Food Allergy vs. Food Intolerance

Knowing whether you’re dealing with a food allergy or a food intolerance is key to managing how you feel and making the right choices for your health.

Food Allergies

Involve the immune system and can trigger rapid, sometimes severe or even life-threatening reactions.*
Always require medical testing and guidance from a healthcare professional.*

Food Intolerances

Usually involve the digestive system, enzyme activity, or cellular responses that make it harder for your body to process certain foods.*
Symptoms tend to develop more gradually and are typically less severe, but they can still significantly impact how you feel day-to-day.*

Understanding this distinction empowers you to take the right next steps and build a wellness plan that truly supports your body.

What is a Food Allergy?

Food allergies can trigger reactions ranging from mild to potentially life-threatening. Even a small amount of the allergen can cause symptoms to appear within seconds or minutes.

Mild Symptoms

Coughing or wheezing
Coughing or wheezing
Runny or stuffy nose
Watery, red, or puffy eyes

Severe Symptoms

Tingling in the mouth
Swelling of the lips, tongue, face, or throat
Hives
Anaphylaxis, which may include
- Tightened airways
- Severe drop in blood pressure (shock)
- Dizziness, fainting, or loss of consciousness
- Rapid heartbeat

Why do allergies develop?

Food allergies can develop at any stage of life, though they’re more common in young children and often persist into adulthood. Scientists don’t yet fully understand why or how allergies develop.

Recognizing and Testing Allergies

If you notice symptoms that may resemble a food allergy, consult a doctor or allergy specialist as soon as possible. Seek emergency medical care immediately if you experience signs of anaphylaxis, such as difficulty breathing, severe swelling, or a rapid drop in blood pressure.

Allergies are typically diagnosed through blood tests or skin prick tests. Blood tests measure immune responses — including IgE and other antibody levels — to help identify potential triggers. Skin prick tests involve applying small amounts of allergens to the skin to observe how your body reacts, helping healthcare providers pinpoint the source of the allergy and guide appropriate treatment.*

Our wellness tests cannot diagnose an allergy, nor are they intended to cure, diagnose or treat any medical related health condition.

Food Intolerance vs. Sensitivity

Food intolerances or sensitivities often causedelayed reactions, typically involving the digestive system or subtle cellular responses to certain triggers. Symptoms can appearhours or even daysafter eating, which can make it challenging to pinpoint the exact cause — especially when multiple foods have been consumed in that timeframe.*

Food Intolerances

Food intolerance symptoms can vary from person to person and often develop gradually. They may include:

Digestive changes, such as bloating, gas, constipation, diarrhea, or flatulence*
Increased mucus in the throat or nasal passages*
Skin concerns, including acne, rosacea, eczema, or psoriasis*
Water retention or changes in weight*
Low energy levels or feelings of fatigue*

Please note: These symptoms are not exclusive to food intolerances and may be related to other conditions. Always consult a qualified healthcare professional for concerns about your health.

Testing Food Intolerances

Hydrogen Breath Test
Measures hydrogen gas in your breath after consuming certain sugars such as lactose, glucose, or fructose. This test is typically used in clinical settings to help identify possible intolerances related to specific carbohydrates.

Food Diary / Elimination Approach
Tracking what you eat and drink — and how your body responds — over several days or weeks can help reveal potential trigger foods. Gradually removing and reintroducing certain foods under professional guidance is a common way to explore intolerances.

Food Sensitivity or Intolerance Testing
At-home tests may use samples such as blood, hair, or a mouth swab to provide additional insights. Results can take days or weeks to process and are generally intended to offer information that supports further discussion with a healthcare professional.*

Other Symptoms of Food Sensitivity

Explore the various symptoms that may arise from food intolerances or sensitivities, affecting digestion and overall well-being.

Caffeine Sensitivity

When people produce less of a liver enzyme called CYP1A2. This plays a role in how quickly the liver metabolizes caffeine.

Sulfite Sensitivity

This is when people may have a partial deficiency of the enzyme sulfite oxidase, which helps break down sulfites in food items such as dried apricots, canned fruits, wine, and cereals.

FODMAPS

When a group of sugars ferment in the digestive tract due to an imbalance in bacteria. Enzymes such as amylase and glucoamylase, cellulase, lactase and invertase, and other enzymes break down FODMAPs. FODMAP foods include beans and lentils, some vegetables such as onions, garlic, and cauliflower, some fruits such as apples, cherries, and mango.

Sucrose Intolerance

Sucrose intolerance or genetic sucrase-isomaltase deficiency (GSID) is the condition in which sucrase-isomaltase, an enzyme needed for proper metabolism of sucrose (sugar) and starch (e.g., grains), is not produced or the enzyme produced is either partially functional or non-functional in the small intestine. Sucrose is found in sugar, sugary drinks, fast food, and baked goods.

Sugar Alcohol Sensitivity

(sorbitol, mannitol, maltitol, lactitol, isomalt) - this is when a series of sugar alcohol enzymes are deficient in the body, causing bloating and gastrointestinal distress. Sugar alcohols are found in most jellies, candies, ice creams, chocolate, chewing gums, protein powders, prunes, and berries.

Fructose Intolerance

Alterations in the ALDOB gene can cause hereditary fructose intolerance. The ALDOB gene provides instructions for making the aldolase B enzyme. This enzyme is found primarily in the liver and is involved in fructose breakdown (metabolism), so this sugar can be used as energy. Fructose is found in most fruits.

Enzyme activity and low-grade inflammation can contribute to food intolerances without involving the immune system. Immune-mediated reactions are typically measured by IgE or IgG antibodies — which is why these markers are used in allergy testing, not in most intolerance or sensitivity assessments. This is a common point of confusion, as food intolerances are usually not associated with IgE or IgG responses.

While food allergies and food intolerances are often discussed together, they differ significantly in how they develop, how they present, and how they’re measured. Allergies are immune-driven and can trigger immediate reactions, whereas intolerances and sensitivities tend to develop gradually and are influenced by factors such as diet, environment, and lifestyle.

Some individuals choose to repeat intolerance or sensitivity testing periodically to track how their responses may change over time. Doing so may help them make more informed decisions about their diet and lifestyle and support overall wellness.

Please note: Our testing is designed for wellness and informational purposes only. It is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare provider regarding medical testing, diagnosis, or treatment.

Dr. Sony S.

Panel Expert, Medical Doctor

The Takeaway

Allergies vs. Intolerances: They’re Not the Same Thing

The two might sound similar, but they work very differently. Food allergies typically involve your immune system, and even the tiniest trace of a trigger can set off a reaction — sometimes within minutes — which is why ruling them out first is so important.

Food intolerances, on the other hand, may involve your digestive system and cellular responses. They’re usually not life-threatening, but they can still make you feel lousy. And because they build more slowly, you might need to eat a larger amount of the trigger food before you notice anything — and the symptoms can take hours or even days to appear.

It’s also possible to be intolerant to something without being allergic to it — or vice versa. Your immune system and your digestive system don’t always react the same way, which is why understanding the difference matters.*