Question: What's Involved in a Gluten Challenge?
Answer: If you decided to go gluten-free before getting tested for celiac disease but 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. Once people who have celiac go gluten-free, their blood antibodies to gluten disappear and their intestinal damage heals, meaning the tests won't show anything.
Why Undergo a Gluten Challenge?
Physicians recommend that anyone considering a gluten-free diet get tested for celiac disease prior to going gluten-free. 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 don'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 To Perform a Gluten Challenge
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.
A few doctors say that eating a little gluten each day (a slice of regular bread or two) for a week or 10 days will be enough to spur your body to produce antibodies and create the type of intestinal damage that your doctor will look for in an endoscopy. Unfortunately, studies show that almost certainly won't be long enough for damage to occur.
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 Symptoms Often Intolerable
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. I've also heard of 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 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 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, you can consider celiac disease gene testing.
This won't tell you if you have celiac (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.
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, you'll be risking serious complications (including additional autoimmune conditions or even, rarely, cancer) if you cheat.
Beth Israel Deaconess Medical Center clinical trial notice. "Serum Markers in Gluten Challenge." Updated Jan. 20, 2011.
Bruins M.J. The clinical response to gluten challenge: a review of the literature. Nutrients. 2013 Nov 19;5(11):4614-41.
C. Pyle et al. Low-Dose Gluten Challenge in Celiac Sprue. Clinical Gastroenterology and Hepatology, July 2005.