The Difference Between Food Sensitivity and Food Allergy
by: Dr. Paul Chang, General Practitioner, Regis Medical
Why Understanding the Difference Matters
Many people use the terms food allergy and food sensitivity interchangeably. However, the two are very different — both in how they affect your body and how they should be diagnosed and managed. Misunderstanding them can lead to unnecessary restrictions, persistent symptoms, or even missed diagnoses.
What is a Food Allergy?
An Immune System Overreaction
A food allergy is an immune-mediated reaction, typically involving IgE (Immunoglobulin E) antibodies, where your body reacts to a specific food protein as if it’s a threat.
Common Symptoms of Food Allergy:
- Hives, rash, or itching
- Swelling (especially lips, tongue, throat)
- Wheezing or shortness of breath
- Abdominal pain, vomiting
- Anaphylaxis — a severe, life-threatening reaction
Foods Commonly Linked to Allergies:
- Peanuts and tree nuts
- Shellfish and fish
- Eggs
- Milk
- Wheat
- Soy
Food allergies usually trigger immediate symptoms — often within minutes to a few hours.
What is a Food Sensitivity (or Intolerance)?
A Delayed, Non-IgE Reaction
Food sensitivities (also referred to as food intolerances or delayed hypersensitivities) involve the immune system in a more subtle and delayed way — typically via IgG (Immunoglobulin G antibodies). They do not cause life-threatening reactions but can lead to chronic inflammation and discomfort over time.
Symptoms of Food Sensitivity May Include:
- Bloating and gas
- Fatigue
- Headaches/Migraines
- Joint pain
- Brain fog
- Skin conditions like acne or eczema
- Mood changes
Symptoms can appear hours or even days after consuming the offending food, making it difficult to pinpoint without testing.
Food Sensitivity vs. Food Allergy: Key Differences
If you're experiencing symptoms like these and they’re interfering with your daily life, it’s time to get answers. A simple blood test could uncover hidden triggers and help you feel more energetic, focused, and symptom-free.
How to Test for Food Sensitivities vs Allergies
Food Allergy Testing (IgE):
- Skin prick tests
- Serum IgE blood tests
- Medically supervised oral food challenge (gold standard)
Food Sensitivity Testing (IgG):
- IgG food intolerance blood test (often done in clinics)
- Elimination and reintroduction diet (time-consuming and hard to track without support)
Why Food Sensitivities Often Go Undiagnosed
Because food sensitivities present subtly and over time, many people live with ongoing symptoms — misattributing them to stress, poor sleep, or aging. This often leads to:
- Overtreatment with medications (for symptoms like bloating or fatigue)
- Unnecessary restrictive diets
- Overlooking the root cause — immune reactivity to food
Chronic Inflammation: The Hidden Impact of Food Sensitivities
Long-term exposure to trigger foods can lead to gut inflammation, leaky gut, and systemic low-grade inflammation, which is associated with:
- IBS symptoms
- Autoimmune conditions
- Mood disorders
- Chronic fatigue
- Skin disorders like eczema and acne
- Chronic headache or migraine
What You Can Do If You Suspect a Food Sensitivity
When to Consider a Food Intolerance Test
Long-term exposure to trigger foods can lead to gut inflammation, leaky gut, and systemic low-grade inflammation, which is associated with:
- Persistent bloating, fatigue, or skin issues
- Symptoms without a clear cause
- Multiple food reactions
- No improvement with typical dietary changes
Consult a medical professional or dietitian to:
- Get tested with an IgG food intolerance blood test
- Create a structured elimination and reintroduction plan
- Monitor symptom improvement without risking nutritional deficiencies
Final Thoughts: Don’t Confuse Food Sensitivities with Allergies
Food allergies and food sensitivities affect the body differently, and both require tailored approaches to diagnosis and management. If you’re living with unexplained chronic symptoms, identifying hidden food sensitivities may be the missing link.
Screen for Food Intolerances with Regis Medical
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