Gluten Issues: Is It Celiac Disease, an Intolerance or a Wheat Allergy?

If eating food with gluten gives you a bellyache, you might be dealing with celiac disease. Of course, gastrointestinal (GI) issues from gluten could also signal a sensitivity to the protein. Or maybe even a wheat allergy.

The truth is, any of those three could be a reason to remove wheat or other grains from your diet. But while they seem similar in many ways, the conditions are vastly different:

• Celiac disease is an autoimmune disorder where eating gluten damages your small intestine.
• A gluten intolerance or non-celiac gluten sensitivity (NCGS) is when you test negative for celiac but react badly to gluten.
• A wheat allergy is when your immune system overreacts to wheat.

Confused? Yeah — that’s understandable. So, let’s take a closer look at each condition with the help of gastroenterologists Alberto Rubio Tapia, MD, and Claire Jansson-Knodell, MD.

Celiac disease vs. NCGS (gluten intolerance)

Celiac disease and gluten sensitivity often act like twins. Both can bring nearly identical symptoms after you eat gluten, ranging from gut issues like gas and nausea to fatigue, headaches and depression.

In each case, too, those uncomfortable symptoms tend to ease and disappear when you cut gluten from your diet.

But that’s where the similarities end.

“The biggest difference is that with celiac disease, gluten causes damage to your small intestine,” says Dr. Jansson-Knodell. “With a sensitivity, there’s no damage occurring. You may feel poorly, but there isn’t any physical harm being done to your body.”

Despite celiac taking a heavier toll, it won’t necessarily feel worse than gluten sensitivity.

“Some people with celiac have no symptoms at all,” adds Dr. Rubio Tapia. “And a person with NCGS could have very severe symptoms after eating gluten.”

There’s also a chance that gluten intolerance may not be a reaction to gluten at all. Instead, it could be a reaction to another protein found in the most common grains we eat — called amylase/trypsin-inhibitors, or ATIs, which are particularly high in wheat.

“ATIs could be causing symptoms in people with NCGS, but we need more studies to find out,” he says. “We know people with NCGS get relief when they stop eating gluten. But when you go gluten-free, you also go ATI-free because these proteins are in the same foods.”

How is a wheat allergy different from celiac or NCGS?

A mild wheat allergy can cause many of the same classic GI symptoms as celiac or NCGS when you eat food with gluten. That includes abdominal pain, vomiting, nausea and more.

But a wheat allergy differs in that it may also bring respiratory and skin issues.

“You could experience things like wheezing, swelling and nasal itching — or even anaphylaxis,” says Dr. Jansson-Knodell. “People with a wheat allergy also may see hives appear on their skin.”

Food allergies are an overreaction that happens when your immune system views something you eat as a threat. If you have a wheat allergy, you’ll react every time you eat something with wheat, even a tiny amount.

People with severe allergies can even react to inhaling or smelling wheat, even if they don’t eat it. (This type of reaction won’t happen if you have celiac or NCGS.)

Which condition is most common?

NCGS is by far the most common cause of issues related to eating gluten. It’s estimated that up to 10% of the population may have some sort of sensitivity to the protein. Many of those are undiagnosed.

Celiac disease, by comparison, affects about 1% of the population. Celiac runs in families, so your odds of having it increase if you have a first-degree relative — like a parent, sibling or child — with the disease.

A wheat allergy is the least common, affecting about 0.2% of the population. It’s also more common in childhood than adulthood. “Many kids outgrow the allergy around age 16,” reports Dr. Jansson-Knodell.

Figuring out which condition you might have

If eating gluten gives you trouble, it’s important to get an answer as to why — particularly given the potential health consequences that can come from celiac disease.

“It’s important to get tested because celiac disease can cause long-term damage to your intestines,” stresses Dr. Rubio Tapia. “You need to know if you have celiac so you can strictly avoid gluten and stay healthy.”

It’s best to see a healthcare provider if you have:

• A parent or sibling with celiac disease, as your provider may want to test you for celiac, even if you don’t have symptoms
• Symptoms of celiac disease, NCGS or a wheat allergy when you eat gluten
• Other health conditions, like Type 1 diabetes or autoimmune conditions, which make you more likely to have or develop celiac disease

Testing for celiac disease

If your provider thinks you could have celiac disease, they may recommend:

• Antibody test: You might need a blood test to check for tissue transglutaminase IgA antibodies (tTG-IgA). Your body makes these antibodies after you eat gluten if you have celiac disease.
• Genetic test: A blood test can check for genes related to celiac disease. A negative genetic test result usually rules out celiac disease. But a positive result means you need further testing to confirm the diagnosis.

If blood tests show you have celiac antibodies, your provider may take a biopsy (sample) of the inside of your small intestine to look for signs of damage caused by celiac disease.

It should be noted that tests for celiac only work if you’re still eating gluten.

“That’s why you shouldn’t self-diagnose and just go gluten-free,” explains Dr. Rubio Tapia. “See your provider first and have tests done before eliminating any foods from your diet.”

Testing for a wheat allergy

If your provider thinks you could have an allergy to wheat or another grain, like barley or rye, they may do:

• Blood tests: People with a wheat allergy have immunoglobulin E antibodies (IgE) to wheat protein.
• Skin-prick test: Your provider uses thin, short needles to place a small amount of wheat protein just under your skin. If your skin reacts with redness, swelling or hives, you may have a wheat allergy.
• Oral food challenge: While a medical team watches you closely, you eat a small amount of wheat. The team is prepared to give you epinephrine, which stops anaphylaxis. (Dr. Rubio Tapia notes that this test is rarely needed.)

Diagnosing gluten intolerance

There isn’t any specific test for gluten intolerance. Instead, a diagnosis of NCGS usually requires two things:

1. Negative blood tests for celiac disease.
2. Feeling better when you stop eating gluten.

“We diagnose NCGS when we rule out celiac disease and wheat allergy,” explains Dr. Rubio Tapia.

If you learn you have a gluten sensitivity, you might wonder if celiac disease is waiting in the wings. Rest easy on that one: There’s no evidence to support that the two conditions are related.

“People with NCGS do not have a higher risk of celiac disease,” he adds. “It’s natural to worry about this because the two seem like similar conditions, but they’re not connected at all.”

Final thoughts

Once you know why eating gluten causes you issues, you can follow the proper course of action to minimize them.

If you have celiac disease or a severe wheat allergy, adopting a strict gluten-free diet is a priority. There are resources available to help you avoid gluten in your meals. (It’s in more food than you might expect, too.)

For people with a gluten sensitivity, it comes down to the amount of gluten that creates discomfort. Try to eat in a way where you feel good at the end of the meal.

Bottom line? “All of these conditions can be managed,” reassures Dr. Jansson-Knodell. It’s just a matter of knowing which one you need to address.