Gluten-related disorders: distinguishing facts from fantasies

Last Updated: 2017-08-15

By Megan Brooks

NEW YORK (Reuters Health) - The prevalence of celiac disease and nonceliac gluten sensitivity is rising, and more people are trying a gluten-free diet for a variety of signs and symptoms without a clear diagnosis. But distinguishing between celiac disease and nonceliac gluten sensitivity is important for long-term therapy, experts say.

In a review paper in JAMA, online August 15, they provide an evidence-based update on the pathophysiology, diagnosis and treatment of celiac disease and nonceliac gluten sensitivity.

"Nowadays there is an increased interest in embracing the gluten-free diet as a way to mitigate a variety of chronic illnesses or just as a strategy to implement a healthier lifestyle," review author Dr. Alessio Fasano, director of the Center for Celiac Research and Treatment at Massachusetts General Hospital in Boston, told Reuters Health by email.

"These claims are broadly made with not much support from strong clinical and/or scientific evidence. Therefore, with this review we mainly intended to distinguish facts from fantasies and to guide healthcare providers, particularly general practitioners, in providing guidance on who should implement a gluten-free diet as part of a medical intervention," said Dr. Fasano.

"Until the recent past we were convinced that the only indication for a gluten-free diet was celiac disease, an immune-mediated disorder that causes damage of the intestine with subsequent onset of intestinal and/or extraintestinal symptoms. Now we know that another clinical entity named nonceliac gluten sensitivity can be triggered by the ingestion of gluten-containing grains," Dr. Fasano explained.

"In this systematic review we highlighted similarities and differences between these two clinical entities, discussing how to diagnose and manage them, despite the fact that they cannot be distinguished based on their clinical presentation," he added.

The authors note in their review that screening for celiac disease must happen before a gluten-free diet is implemented, because once a patient starts such a diet, testing for celiac disease is no longer accurate.

The past two decades have seen an increase in the availability and use of accurate noninvasive tools for diagnosing celiac disease, note the authors. Their review summarizes the sensitivity and specificity of each test and provides recommendations for their use.

"Patients with celiac disease should be followed up closely for dietary adherence, nutritional deficiencies, and the development of possible comorbidities," the authors write.

For nonceliac gluten sensitivity, no specific biomarkers have yet been identified and validated, they point out. "Clinicians should suspect nonceliac gluten sensitivity in a patient who presents with gastrointestinal or extraintestinal symptoms that appear to improve with a gluten-free diet," they advise.

As for treatment, Dr. Fasano and coauthors say, "Currently, a strict gluten-free diet remains the only available treatment for gluten-related disorders, but the time frame is different according to the specific disorder. It has been suggested that nonceliac gluten sensitivity may be a transient condition. Therefore, expert recommendation is that the gluten-free diet should be followed for a given period, e.g., 12 to 24 months, before testing gluten tolerance again. Based on severity of symptoms, some gluten-sensitive patients without celiac disease may choose to follow a gluten-free diet indefinitely. For patients with celiac disease, life-long implementation of a strict gluten-free diet is the only option."

The review also addresses several "practical questions," including whether family members should be screened. "First-degree family members of patients with celiac disease have up to a 15- to 25-fold higher frequency of developing celiac disease based on their genetics, compared with individuals without a first-degree family member with celiac disease," the authors note. For that reason, several organizations, including the American College of Gastroenterology (ACG), suggest screening first-degree family members with or without signs or symptoms concerning for celiac disease, they note.

This research had no commercial funding. Dr Fasano reported receiving a grant for sponsored research from INOVA Diagnostics; receiving speaking fees from Mead Johnson Nutrition; and that he is cofounder of, and a stockholder in, Alba Therapeutics, which makes products for the treatment of autoimmune and inflammatory diseases.

SOURCE: http://bit.ly/2x0UH8f

JAMA 2017.