The Gluten Challenge

The Gluten Challenge

How to test and diagnose celiac disease after you have already stopped eating gluten

If you decided to stop eating gluten before getting tested for celiac disease and now have decided to undergo the testing, your doctor may recommend you undergo a gluten challenge. That means you’ll need to eat gluten…potentially lots of it.

In effect, you’ll be “challenging” your system with gluten, which is where the term “gluten challenge” originates.

You need to eat gluten for celiac disease testing to be accurate. That’s because the tests, which include blood tests and an endoscopy to look for damage to your intestines, actually look for your body’s reaction to gluten.

If you’re not eating a typical gluten-filled diet, you won’t have that damage, even if you do have celiac disease. Once people who have celiac begin a gluten-free diet, their blood antibodies to gluten disappear and their intestinal damage heals, meaning the tests won’t show anything.

Why Do a Gluten Challenge

Physicians recommend that anyone considering a gluten-free diet get tested for celiac disease prior to eliminating gluten from their diets. But despite that recommendation, many people go gluten-free without testing because they’ve heard it might make them feel better, or because they believe it might be a healthier way to eat.

However, without test results for celiac disease, those people won’t know whether they’re at risk for complications of celiac, including osteoporosis and malnutrition. Generally, you can keep these complications at bay by following a strict gluten-free diet, but people without a diagnosis might not be as motivated not to cheat on the gluten-free diet as someone who’s been diagnosed.

There’s another reason often cited by people undergoing a gluten challenge: leverage to urge family members to also get tested for celiac disease. Current medical guidelines call for testing of all close relatives once someone in the family is diagnosed with celiac.

How It Works

A gluten challenge involves eating gluten only after you’ve been gluten-free for a while. But how much gluten do you need to eat, and for how long?

Unfortunately, there are no established medical guidelines for performing a gluten challenge, although the little research there is on this subject indicates that more gluten for a longer time period will give you better odds of accurate test results.

Although it is not clear for how long this gluten exposure needs to be, most physicians suggest six to eight weeks of exposure as tolerated. If one cannot tolerate this duration of exposure due to severe symptoms, a shorter duration can be considered with earlier endoscopic evaluation and checking celiac serologies two to four weeks after the gluten challenge has been completed. The longer one stays on a gluten containing diet, the better the chance that an accurate diagnosis based on serologies and small bowel biopsies can be made. 

Sometimes gluten challenges start off more slowly to build up the amount of gluten ingested over time. In as little as two weeks, up to 75% of patients with celiac disease will have an increase in celiac antibodies. On the other hand, this also means that 25% patients with celiac disease may be missed at a two week blood test. Research has shown that three-week-long gluten challenges involving the equivalent of one to three slices of bread a day are not enough to generate antibodies and intestinal damage in known celiacs who have been following the gluten-free diet.

Many physicians recommend a six- to eight-week gluten challenge, in which you’ll need to eat two slices of gluten-filled bread each day. But there’s no real research showing that’s enough, either.

An analysis of the few medical studies that have been 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 three months.

Gluten challenge should only be considered in patients who don’t have severe reactions to gluten ingestion. The challenge typically requires the consumption of  about 8 to 10 grams of gluten per day. One slice of bread is contains approximately 2-3 grams of gluten so one would expect to eat the equivalent of two to four slices of bread per day. 

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. However, it’s not clear how severe your symptoms might become over the course of your challenge.

Some people see a return to severe symptoms almost immediately (within a day or two) and continue to have bad symptoms as long as they eat gluten. It is also possible for  people’s overall health to deteriorate dramatically over the course of a gluten challenge.

Some people may feel sick early in the challenge, but then not notice too many symptoms as they continue to eat gluten. Others might not notice any symptoms at all from their gluten ingestion.

If you do experience severe symptoms, including nausea and vomiting, severe diarrhea, dizziness or bad abdominal pain, you should talk to your doctor about whether you should continue with your gluten challenge.

Gluten challenge should be avoided in people who are still undergoing active growing such as young individuals (especially under five years of age) as this could affect critical growth periods and delayed growth. 

Alternatives

Sadly, there’s no way to definitively diagnose celiac disease in someone who’s not currently eating gluten. That’s one reason why physicians urge those considering a gluten-free diet to get tested first.

However, there are two alternatives to undergoing a gluten challenge. Neither will provide you with a “gold standard” diagnosis, but you may decide (after consulting with your physician) that you don’t need that official diagnosis.

If you want some indication of whether you might have celiac disease, you can consider genetic testing. This won’t tell you if you have celiac disease (a large percentage of the population carries the genes for celiac disease). But it will tell you if it’s possible for you to have celiac disease.

You also can consider skipping the gluten challenge and the testing altogether and continuing to eat gluten free. This is a common decision for people who get horrible symptoms from accidental gluten ingestion.

However, if you do decide to remain gluten-free without testing, you should commit to following the diet strictly, since if you do have celiac disease, you’ll be risking serious complications (including additional autoimmune conditions or even, rarely, cancer) if you cheat.

How Much Gluten Is In My Food?

For reference, each of these items contains approximately 2-2.5grams of gluten:

  • 1 slice of wheat based bread
  • 1 Weet-bix
  • ½ English muffin
  • ½ cup wheat based cereal
  • ½ cup of cooked wheat based pasta
  • 8-10 saltine crackers
  • ½ large dinner roll

A typical gluten challenge requires two to four servings of any of the above per day.