Food Sensitivity vs. Food Allergy vs. Intolerance — What’s the Difference?
f you or your child experience bloating, rashes, fatigue, or mood changes after eating certain foods, you’re not alone. But not all food reactions are the same — and understanding which type you’re dealing with can make all the difference in treatment and healing.
At Sun Valley Natural Medicine, we help patients uncover the root causes of food reactions using a functional medicine approach. Here’s a clear breakdown of the three main types: food allergy, food intolerance, and food sensitivity.
1. Food Allergy — the Immune System on High Alert
A food allergy involves an immediate immune response, typically mediated by IgE antibodies. Symptoms can occur within minutes to hours and may include:
Hives or swelling
Itchy mouth or throat
Wheezing or difficulty breathing
GI distress (nausea, vomiting, diarrhea)
In severe cases, anaphylaxis
Common allergens: Peanuts, tree nuts, dairy, eggs, soy, shellfish, and wheat.
Because food allergies can be life-threatening, they require strict avoidance and may involve an EpiPen or emergency plan.
2. Food Intolerance — a Digestive Issue, Not Immune-Driven
A food intolerance occurs when your digestive system has trouble breaking down a food — no immune activation involved. The reaction is typically dose-dependent and affects the gut, not the immune system.
Common examples:
Lactose intolerance: Deficiency of the lactase enzyme, leading to gas, bloating, and diarrhea.
Fructose intolerance: Trouble absorbing certain sugars.
Histamine intolerance: Difficulty breaking down histamine in foods like aged cheese, wine, and smoked meats.
Functional medicine can help by supporting enzyme production, microbiome balance, and gut repair so you can tolerate more foods comfortably.
3. Food Sensitivity — the Delayed, Inflammatory Response
Food sensitivities are immune-mediated, but through IgG or complement pathways rather than IgE. They typically cause delayed symptoms (hours to days later) and can affect multiple systems in the body.
Common symptoms:
Bloating or constipation
Brain fog or fatigue
Skin rashes or eczema
Joint pain
Mood changes or anxiety
Food sensitivities often stem from gut permeability (“leaky gut”), microbiome imbalance, or chronic stress affecting digestion.
Testing (such as MRT or IgG panels) can help guide an elimination diet — but true healing requires addressing the gut-immune connection.
4. The Functional Medicine Approach at Sun Valley Natural Medicine
We look beyond “what foods to avoid” and focus on why the reaction is happening.
Our process often includes:
Comprehensive gut testing (microbiome, inflammation, permeability)
Personalized elimination or rotation diets
Nutrient repletion and digestive support
Mind-gut regulation for stress resilience
Healing the gut often means that foods once triggering sensitivities can eventually be reintroduced safely.
5. Takeaway: Listen to the Body, Don’t Just Eliminate
Whether your reaction is an allergy, sensitivity, or intolerance, your body is sending a signal that something is out of balance. With the right testing and a personalized plan, it’s possible to rebuild tolerance, calm inflammation, and restore digestive peace.
Ready to Get to the Root?
If you suspect food reactions are affecting your energy, skin, digestion, or mood, our clinicians at Sun Valley Natural Medicine can help uncover the root cause and create a plan for long-term healing.
Learn more or schedule a visit at Sun Valley Natural Medicine