What Is a Gluten Challenge?

A gluten challenge is when you intentionally eat gluten for several weeks after going gluten-free in order to monitor symptoms and get accurate celiac disease test results.

Celiac disease is an autoimmune disease in which eating gluten—a protein found in wheat, barley, and rye—triggers an immune response that damages the lining of the small intestine.

Gluten must be in your system in order for testing to confirm celiac disease. This article will explain why, plus what's involved in a gluten challenge, the risks of undiagnosed celiac disease, and what to expect when being tested.

Purpose of a Gluten Challenge

A gluten challenge is done so that tests that can diagnose celiac disease can be performed.

You need to be consistently eating gluten for celiac disease testing to be accurate. That's because blood tests and intestinal tissue sample evaluations look for your body's reaction to the protein.

Confirming celiac disease is important, as the diagnosis requires you to make diet changes to stay well. It also puts you at higher risk of certain complications that need to be monitored for.

Advises Diet Changes

Getting tested for celiac can tell you whether or not you need to follow a lifelong gluten-free diet.

It will determine how strict you may need to be about reading labels. For example, a food that seems like it would be gluten-free may have a hidden source of gluten, such as a preservative or thickener. That can be enough to trigger inflammation and symptoms if you have celiac.

Likewise, if you do have celiac, you will also need to be diligent about how and where your food is prepared. Cross-contamination—when gluten ends up in a meal even though the ingredients are gluten-free—can also trigger celiac symptoms. This could occur with something as simple as a restaurant cutting vegetables for your salad on a cutting board that was just used to slice bread.

Raises Awareness of Risks

If celiac goes untreated and/or you are still ingesting gluten, even accidentally, it can lead to intestinal damage.

This damage makes it more difficult to absorb essential nutrients properly, which can lead to deficiencies and a range of complications, such as bone loss, fertility issues, and increased risk of some cancers.

Generally, you can reduce your risk of complications by following a strict gluten-free diet. But you won't know to do this without having undergone a gluten challenge to confirm celiac disease.

Knowing you have celiac helps your healthcare provider monitor for complications and take steps, such as recommending nutritional supplements, to avoid them.

Why Gluten Is Needed for Celiac Tests

Whenever your body senses something foreign, it produces antibodies—blood proteins intended to "neutralize" the invader.

Gluten is, of course, not inherently harmful. But in those with celiac disease, the body believes otherwise and treats it as such.

Antibodies need time to build in the bloodstream before they can be detected by blood tests. If you think you have celiac and go gluten-free before getting an official diagnosis, your antibodies to gluten may disappear. You can have testing done, but the markers of celiac may simply not be there anymore.

Likewise, if you have celiac and don't consume gluten for a period of time, your intestinal damage can heal. An endoscopy, which is a procedure to examine the small intestine, may not reveal any issues.

Though gluten may very well be causing your symptoms, following a gluten-filled diet in advance of testing is necessary to ensure accurate results.

In fact, that's where the "challenge" part of a gluten challenge comes from: You are purposefully presenting the body with gluten to see if it can tolerate it.

Blood Tests

The primary antibody test used is the tissue transglutaminase IgA (tTG-IgA test), which is the most sensitive for detecting celiac disease.

But some people have a condition known as IgA deficiency that can cause false-negative results on antibody tests for celiac disease.

Therefore, an additional immunoglobulin A (IgA test) is typically given to make sure you generate enough of this antibody for the celiac disease test results to be accurate.

Endoscopy

If the results of the antibody tests are positive or if your symptoms resume intensely during the gluten challenge, your healthcare provider may suggest an endoscopy.

You will be sedated, and a gastroenterologist, a physician who specializes in diseases of the digestive tract, will insert a small tube with a camera through your mouth and into the digestive tract to the small intestine.

This allows them to look for damage and inflammation characteristic of celiac disease.

It's also an opportunity to get samples of the intestinal lining that can be studied more closely under a microscope. Damage to the villi, fingerlike projections that line the small intestine and assist in food absorption, are indicative of celiac.

An endoscopy with biopsies is the "gold standard" for diagnosing celiac disease since there is a risk of false positive or false negative results on blood tests.

Skin Biopsy

Some people with celiac disease develop a blistering skin rash from eating gluten that's itchy and painful. This rash is called dermatitis herpetiformis.

If you develop a skin rash during the gluten challenge, a small skin sample can be taken to test for antibodies. This testing can be used to help diagnose both dermatitis herpetiformis and celiac disease.

How to Perform a Gluten Challenge

Unfortunately, there are no established medical guidelines for performing a gluten challenge.

The little research there is on this subject indicates that more gluten consumed over a longer time period will give you better odds of accurate test results.

Never undergo a gluten challenge without a healthcare provider's guidance and oversight. Always follow their specific instructions.

Challenge Duration

Many healthcare providers recommend that you eat the equivalent of about two slices of gluten-filled bread each day as part of a gluten challenge before you get tested for celiac.

But even this isn't always enough to accurately diagnose celiac in all cases.

Some healthcare providers will recommend continuing the gluten challenge for up to two years or longer with regular testing if you are symptom-free during the challenge.

An analysis of the few medical studies performed on this issue indicates that between 70% and 100% of children will develop positive celiac blood test results within three months while eating gluten. In adults, between 50% and 100% will show positive test results within the same period.

Symptom Tracking

During the gluten challenge, your healthcare provider may ask you to keep a daily log of what you eat, when you eat it, and any symptoms you experience.

Celiac disease has a wide range of potential symptoms that vary from person to person, so you'll be asked to any changes in how you feel. In particular, keep track of:

• Nausea, vomiting
• Abdominal pain, bloating
• Diarrhea, constipation, or changes in stool
• Mood changes
• Joint pain
• Fatigue
• Headaches
• Mouth ulcers
• Skin rashes
  

Who Shouldn't Do a Gluten Challenge

A gluten challenge is not recommended for:

• Children under age 5
• Those in puberty
• People who are pregnant or trying to conceive
  

Coping With Symptoms

If you get symptoms of celiac disease from accidental gluten ingestion while eating gluten-free, you can expect to get symptoms from a gluten challenge.

How severe your symptoms might become over the course of your challenge is less clear.

Some people see a return to severe symptoms within a day or two and continue to have bad symptoms as long as they eat gluten. There are also people whose overall health deteriorates dramatically over the course of a gluten challenge.

Others might feel sicker early in the challenge, but then not notice too many symptoms as they continue to eat gluten. And some people might not notice any symptoms during the challenge at all.

Stopping Your Challenge Early

If you do experience severe symptoms, including nausea and vomiting, severe diarrhea, dizziness or bad abdominal pain, you should talk to your healthcare provider about whether or not you should continue with your gluten challenge.

If you have severe symptoms, your healthcare provider may recommend you go ahead and get an endoscopy and have intestinal samples taken regardless of how long you've been doing the challenge.

Alternatives

Sadly, there's no way to definitively diagnose celiac disease in someone who's not currently eating gluten.

However, there are two alternatives to undergoing a gluten challenge. Neither will provide you with a firm diagnosis, but you may decide—after consulting with your healthcare provider—that you don't need one to take next steps.

Gene Testing

If you want some indication of whether you might have celiac, you can consider celiac disease gene testing.

This won't tell you if you have celiac since about 30% of the population carries the genes for celiac disease. It only indicates your susceptibility to developing it.

Going Gluten-Free Without a Diagnosis

You also can consider skipping the gluten challenge and the testing altogether and jumping straight to adopting a gluten-free diet. This is a common decision for people who get severe symptoms from accidental gluten ingestion.

However, if you do decide to remain gluten-free without testing, you should commit to following the diet strictly. If you "cheat" and you do have celiac, you could be risking serious complications.

Furthermore, be sure that your healthcare provider is aware of your decision to go gluten-free so that you can be properly monitored, such as for nutritional deficiencies.

Ongoing Research

Preliminary research is examining other testing methods that may one day allow for shorter gluten challenges. One of these is a blood test that measure interleukin-2, a signaling chemical that helps regulate the immune system.

One small study found interleukin-2 to be elevated in people confirmed to have celiac after just one 6-gram (g) dose of gluten, which is equivalent to about three slices of bread.

Another study found that interleukin-2 was the earliest and most reliable measurement in a two-week gluten challenge.

Larger studies are needed to confirm these findings and to develop guidelines for using this testing method.

Summary

A gluten challenge purposefully exposes the body to the protein so that celiac disease can be detected. The challenge typically runs about six to eight weeks.

In those with the diagnosis, the challenge period gives antibodies to gluten time to build up in the bloodstream so they can be detected by blood tests. It also prompts the start of damage to the lining of the small intestine, which can be identified with an endoscopy and biopsy.

There is no standard for a gluten challenge, but it should only be done under the care of a healthcare provider.

A Word From Verywell

While a gluten challenge is done to help you better your health, people often say that sharing their results with family members is a good way to motivate them to get tested for celiac disease as well.

Medical guidelines suggest celiac testing for close relatives, especially first-degree relatives (parents, siblings, children), once someone in the family is diagnosed with celiac.

Knowing this may be particularly helpful for loved ones who are ignoring their symptoms or putting off medical care.