Gluten-free diet more of a fad than absolute necessity for many

By Dr. Ananya Mandal, MDFeb 22 2012

Many people claim that gluten sensitivity is on the rise and consequently gluten-free products are more popular than ever. A study explores whether shunning gluten is really necessary and finds that in most cases it is not.

Gluten intolerance causes celiac disease, a digestive disease that damages the small intestine and interferes with the absorption of nutrients from food. Celiac disease is diagnosed through blood and bowel tests. But some people not diagnosed with celiac disease can still experience discomfort after eating gluten, a condition which researchers refer to as nonceliac gluten sensitivity. Symptoms of gluten sensitivity include diarrhea, stomach cramps, bloating, headaches, and fatigue.

Nonceliac gluten sensitivity is supposed to be much more common than celiac disease, but there is not much scientific knowledge to support diagnoses. In the new study called, “Nonceliac Gluten Sensitivity: Sense or Sensibility?” published in the Annals of Internal Medicine, researchers from the University of Pavia, Italy, explored the sensitivity that keeps growing in hype but not in understanding. They addressed the debate that gluten-free diets are surfacing in popularity on the internet without any scientific support.

The study finds that there are 4,598 Google citations of nonceliac gluten sensitivity for every science journal article about the condition - more than ten times the number of citations for breast cancer, Alzheimer's disease, lung cancer, or celiac disease itself. The study authors claim that gluten has been called “the new diet villain,” and marketers have estimated 15 to 25 percent of consumers want gluten-free foods.

Gluten is found in products that contain wheat, rye, and barley. In the study, researchers noted that other ingredients in wheat flour or wheat-based foods may actually be causing symptoms that might be attributed to gluten sensitivity. “Gluten is a component of the more complex protein mixture contained in wheat flour. As a consequence, it cannot be considered the sole agent responsible for functional symptoms in persons who eat bread and pasta, and other [starchy] proteins,” wrote the paper authors. Thus, switching to gluten-free breads, cereal, and pastas may not do much to help symptoms.

Dr. David Greenwald, a gastroenterologist at Montefiore Medical Center in New York City, told HealthDay a lot of people who try gluten-free diets do so because they're having symptoms that suggest irritable bowel syndrome (IBS), such as abdominal pain, gas and bloating. The key message of the study is that one should not be too quick to diagnose gluten sensitivity. The authors recommend an “individualized approach” to recognize nonceliac gluten sensitivity, using specific gluten challenge tests on each individual before completely eliminating gluten from the diet.

“Someone who needs to be on a gluten-free diet and is closely monitored can benefit tremendously from it,” Dr. Stefano Guandalini, medical director at the University of Chicago Celiac Disease Center, told WebMD. “But for everyone else, embracing this diet makes no sense.”

While the authors say gluten sensitivity may, in fact, exist in some people without celiac disease, a better diagnostic test is needed to make more accurate diagnoses. The gold-standard test is a double-blind oral “challenge” where patients are given drinks with and without gluten and then asked to rate their symptoms. Neither the patient nor the doctor knows whether the gluten-free or gluten-filled drink was given, so symptoms can be objectively evaluated, but the method is time consuming and costly. Until a better, cheaper test is available, the study authors say doctors can rely on “single-blind” challenge tests - where patients don’t know whether they’re given a gluten or gluten-free drink - to determine whether subjective symptoms such as abdominal pain, nausea, fatigue, or headaches get worse with gluten. They can do an open challenge test - where a gluten drink is administered with a patient’s knowledge - in those who have easy to measure symptoms such as diarrhea, vomiting or a rash thought to be triggered by gluten.