Understanding the Difference Between Food Allergies and Intolerances

If you've ever felt unwell after eating certain foods, you might wonder: is it an allergy or a sensitivity? While the symptoms of food allergies and food intolerances can overlap, the underlying causes and the health risks are very different.

Understanding the distinction between the two is key to managing your reactions, protecting your health, and knowing when to seek medical attention.

The Key Difference: Immune System vs. Digestive System

• Food allergies are triggered by the immune system. When your body mistakenly identifies a food as harmful, it releases immunoglobulin E (IgE) antibodies to attack it. This reaction can range from mild to life-threatening.

• Food intolerances, also called food sensitivities, typically stem from how your digestive system processes certain ingredients. They’re often related to enzyme deficiencies or reactions to food chemicals, and while uncomfortable, they’re not life-threatening.

Symptoms: How to Tell Them Apart

Though some symptoms overlap, there are key differences in how they appear and escalate.

Common Food Allergy Symptoms:

• Abdominal pain

• Diarrhea or vomiting

• Hives or itchy skin

• Swelling of the lips, face, or tongue

• Tight throat, wheezing, or coughing

• Difficulty breathing

• Anaphylaxis (a medical emergency)

Common Food Intolerance Symptoms:

• Bloating or gas

• Abdominal cramps

• Nausea

• Diarrhea

• General digestive discomfort

Anaphylaxis is a rapid, severe allergic reaction that requires immediate medical attention. It can cause low blood pressure, airway swelling, loss of consciousness, or even death if not treated with epinephrine right away.

What Causes Food Allergies vs. Intolerances

Food Allergy Triggers

In allergies, the immune system produces IgE antibodies in response to specific proteins in food. The most common culprits include:

• Dairy: milk, cheese, yogurt

• Eggs

• Peanuts and tree nuts

• Shellfish and fish

• Wheat and soy

• Sesame

Food allergies are more likely in people with other allergic conditions like eczema or asthma, and genetic factors may also increase risk.

Food Intolerance Triggers

Food intolerances tend to result from digestive issues, such as enzyme deficiencies or reactions to food additives. Common triggers include:

• Lactose: due to low lactase enzyme

• Gluten: especially in non-celiac gluten sensitivity

• Histamine: found in aged cheeses, wine, and certain fish

• FODMAPs: fermentable carbs found in garlic, onion, legumes, and sweeteners

• Additives: like MSG, benzoates, sulfites, and artificial colors

Some people may tolerate small amounts of these foods without issue, while others react more severely.

Testing and Diagnosis

If you suspect a food allergy or intolerance, consult a healthcare provider.

For food allergies, testing may include:

• Skin prick test: a small amount of the allergen is introduced to the skin

• Blood test: measures IgE levels in response to specific foods

• Oral food challenge: under medical supervision, small amounts of the food are consumed to observe for a reaction

For food intolerances, diagnosis is more nuanced:

• Elimination diets are the gold standard removing and reintroducing foods to identify triggers

• Breath tests or stool tests may be used for certain intolerances like lactose or fructose malabsorption

• Home test kits are not considered reliable or clinically validated

A qualified dietitian or allergist can help guide your testing process and ensure you’re not cutting out foods unnecessarily.

How Are They Treated?

• Food allergies: Total avoidance is the primary treatment. People with severe allergies often carry an epinephrine auto-injector (like an EpiPen) in case of accidental exposure.

• Food intolerances: Avoidance is also common, though some individuals can tolerate small amounts. Enzyme supplements (like lactase for lactose intolerance) can help reduce symptoms.

When to Seek Emergency Help

Seek immediate medical care if you experience:

• Difficulty breathing or swallowing

• Swelling of the face or throat

• Widespread hives or rash

• Chest tightness

• Repeated vomiting or diarrhea

• Dizziness or fainting

These symptoms could indicate anaphylaxis, which requires emergency treatment.

Bottom Line: Know Your Reaction Type

Food allergies and food intolerances can both impact quality of life, but they require very different approaches. While intolerances often involve digestive discomfort, allergies can be life-threatening if not managed properly.

Understanding your body’s signals and working with a qualified healthcare provider can help you stay safe, enjoy your meals, and make empowered choices for your health.

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