Celiac vs Gluten Sensitivity: The Real Differences

“Oh, you can’t eat gluten? My cousin has that too, she just avoids it for her stomach.”

Is her cousin celiac? Gluten sensitive? Making a lifestyle choice? People use these terms interchangeably, but they’re not the same thing.

Here’s what actually distinguishes them.

The Quick Version

Celiac Disease: An autoimmune condition where gluten triggers your immune system to attack your small intestine. Causes measurable damage. Diagnosed by blood tests and biopsy. Lifelong. Even tiny amounts cause harm.

Non-Celiac Gluten Sensitivity (NCGS): Symptoms from gluten without the autoimmune response or intestinal damage. Diagnosed by exclusion (ruling out celiac). Less well understood. No biomarkers.

Wheat Allergy: A classic allergic reaction (IgE-mediated) to wheat proteins. Not specific to gluten. Diagnosed by allergy testing. Can be life-threatening (anaphylaxis).

Choosing to avoid gluten: A lifestyle or preference without a diagnosis. Not a medical condition.

The Deep Dive: Celiac Disease

The Mechanism

• Autoimmune response to gluten (specifically gliadin)
• Immune system attacks intestinal lining
• Villous atrophy (villi flatten)
• Nutrient malabsorption
• Systemic inflammation affecting multiple organs

Diagnosis

• Blood tests: tTG-IgA, EMA, sometimes DGP
• Genetic markers: HLA-DQ2/DQ8 (necessary but not sufficient)
• Biopsy: Gold standard, shows villous atrophy (Marsh classification)

Characteristics

• Lifelong condition
• Strict avoidance required (20 ppm or less)
• Trace amounts cause damage even without symptoms
• Associated with other autoimmune diseases
• Runs strongly in families (first-degree relatives have 10% risk)

Symptoms (Highly Variable)

• GI: bloating, diarrhea, constipation, pain
• Fatigue, brain fog
• Anemia, osteoporosis
• Skin (dermatitis herpetiformis)
• Neurological issues
• Some people have no obvious symptoms

The Deep Dive: NCGS

What It Is

Symptoms triggered by gluten that resolve when gluten is removed, but without the autoimmune markers or intestinal damage of celiac.

The Mechanism

Honestly? We don’t fully know. Theories:

• Innate immune response (different from autoimmune)
• FODMAPs (carbohydrates in wheat) rather than gluten itself
• Gut microbiome changes
• Increased intestinal permeability
• Other wheat components (ATIs, for example)

Diagnosis

Diagnosis by exclusion:

1. Rule out celiac (blood tests, biopsy)
2. Rule out wheat allergy (allergy testing)
3. Symptoms resolve with gluten-free diet
4. Symptoms return with gluten reintroduction

There’s no biomarker. No test says “NCGS positive.”

Characteristics

• May not be lifelong (some people’s sensitivity changes)
• Threshold tolerance varies (some can handle small amounts)
• No known intestinal damage or long-term complications
• Less clearly defined than celiac
• May be over-reported (people self-diagnose without ruling out celiac)

Symptoms

Often overlap with celiac:

• Bloating, GI discomfort
• Fatigue
• Brain fog
• Headaches
• Joint pain

Why the Distinction Matters

Medical follow-up: Celiac requires ongoing monitoring (blood work, possible bone density screening, associated condition screening). NCGS doesn’t, there’s nothing measurable to track.

Strictness: Celiac requires strict avoidance because damage occurs even without symptoms. NCGS might have a threshold, some people tolerate small amounts or occasional exposure.

Cross-contamination: Critical for celiac. Less clear for NCGS.

Family screening: First-degree relatives of celiacs should be tested. NCGS doesn’t have the same genetic component.

Long-term risks: Untreated celiac increases risk of osteoporosis, certain cancers, other autoimmune diseases. NCGS has no known long-term complications.

The Controversy

NCGS is controversial in the medical community:

Skeptics say:

• It might not exist as a distinct condition
• Many self-diagnosed NCGS cases are actually placebo/nocebo effect
• Some cases are actually undiagnosed celiac
• Some cases are FODMAP sensitivity, not gluten per se

Evidence says:

• Double-blind studies show some people genuinely react to gluten without celiac
• But the effect is smaller than self-report would suggest
• FODMAPs might explain some cases
• More research is needed

What I think: NCGS probably exists but is over-diagnosed through self-report. If you think you have it, get tested for celiac first. If celiac is ruled out and you feel better without gluten, that’s real, even if we don’t fully understand why.

Wheat Allergy: The Third Thing

Often forgotten in the celiac/NCGS discussion:

What it is: A true allergic reaction to wheat proteins (not exclusively gluten).

Mechanism: IgE-mediated immune response. Like a peanut allergy but to wheat.

Symptoms: Can range from mild (hives, itching) to severe (anaphylaxis). Often include respiratory symptoms.

Diagnosis: Skin prick test or IgE blood test.

Treatment: Strict wheat avoidance. Epinephrine for severe reactions.

Key difference: This is allergy, not autoimmune. The mechanism and risks are different.

Which Do You Have?

If you react to gluten-containing foods:

1. Get tested for celiac before going gluten-free. Blood tests and biopsy only work when you’re eating gluten.

2. Consider wheat allergy testing if you have classic allergy symptoms.

3. If celiac and wheat allergy are ruled out and you still react to gluten, you may have NCGS.

4. Don’t self-diagnose. Celiac has serious implications if missed. NCGS has lifestyle implications if misattributed.

Living with the Distinction

If you have celiac: You need strict, permanent avoidance. No exceptions. Regular medical follow-up.

If you have NCGS: You might have more flexibility. Some people tolerate small amounts or occasional exposure. Work with your doctor or dietitian to find your threshold.

If you’re choosing to avoid gluten: That’s your choice. Just know it’s different from a medical diagnosis, and be careful not to claim celiac disease if you don’t have it.

A Word About Social Dynamics

The explosion of gluten-free diets as a trend has been both helpful and harmful for celiacs.

Helpful: More GF products. More restaurant awareness. Better labels.

Harmful: Skepticism. People who think “gluten-free” is just a fad. Servers who don’t take requests seriously.

When you explain your needs, clarity helps:

• “I have celiac disease. It’s an autoimmune condition, not a preference.”
• “Cross-contamination will make me sick.”
• “This isn’t a fad diet, it’s medical treatment.”

Distinguishing yourself from the “gluten is just unhealthy” crowd helps you get taken seriously.

The Bottom Line

Celiac disease and gluten sensitivity aren’t the same. They have different mechanisms, different diagnoses, different implications.

If you haven’t been tested for celiac, get tested, before you go gluten-free. If you’ve been diagnosed with celiac, take it seriously.

And if you have NCGS, respect your symptoms while knowing they’re different from celiac.

Words matter. Accuracy matters. Know what you have.