Food Allergy vs Food Intolerance vs FODMAP Sensitivity: Understanding the Difference

Food Allergy vs Food Intolerance vs FODMAP Sensitivity: Understanding the Difference

By Dr. Onikepe Adegbola, MD PhD — Johns Hopkins-trained physician-scientist

These three concepts get confused constantly — by patients AND by some practitioners. A food allergy can kill you in minutes. A food intolerance makes you uncomfortable. FODMAP sensitivity causes GI symptoms. They involve completely different immune mechanisms and require different management.

Key Takeaways

• Food allergy = immune IgE reaction = can be life-threatening (anaphylaxis) = requires strict avoidance
• Food intolerance = enzyme deficiency or chemical sensitivity = uncomfortable but not dangerous
• FODMAP sensitivity = fermentation by gut bacteria = bloating, gas, pain, diarrhea
• IgG "food sensitivity" tests measure exposure, NOT intolerance — clinically unreliable
• FODMAP digestive enzymes address intolerance and FODMAP sensitivity (NOT allergy)

Comparison

Common Confusions

• "I'm allergic to dairy" — probably lactose intolerant (enzyme deficiency), not allergic (IgE). If you've never had hives/swelling/anaphylaxis from dairy, it's intolerance.
• "I'm allergic to gluten" — probably fructan sensitivity (FODMAP) or celiac (autoimmune). Wheat allergy (IgE) exists but is rare in adults.
• "My food sensitivity test says I'm sensitive to 47 foods" — IgG tests measure EXPOSURE, not pathology. You'd react to everything you eat regularly.

What to Do

1. True allergy → allergist, skin prick test, carry EpiPen
2. Suspected intolerance → FODMAP enzymes + elimination diet
3. FODMAP sensitivity → low FODMAP protocol + probiotics

See our elimination diet guide and testing guide.

This article is educational only. Suspected food allergies require allergist evaluation.