February has been a push-me, pull-me month for those with gluten sensitivity.
First a group of 15 international celiac disease experts gave gluten sensitivity its own category in a list of gluten-related disorders. The researchers, writing in the journal BMC Medicine, also proposed a specific way to diagnose gluten sensitivity. Both were seen as positives for people who get sick when they eat gluten, but don't have celiac disease.
According to the experts, gluten-sensitivity should only be diagnosed after first ruling out wheat allergies, celiac disease and gluten ataxia, using blood and other tests that can pinpoint those recognized disorders. Second, diagnosis should include testing for AGA antibodies in the blood, though these are not always present. Third there should be improvement in symptoms on a gluten-free diet. Finally, a double-placebo gluten challenge in which neither the patient nor doctor knows when gluten-containing foods are being consumed should be conducted.
“Some individuals who experience distress when eating gluten containing products and show improvement when following a gluten-free diet may have gluten sensitivity instead of celiac disease,” concluded researchers including Alessio Fasano, MD, of the University of Maryland Center for Celiac Research and Peter Green, MD, of the Celiac Center at Columbia University.
But even as word of the proposed diagnostic system for gluten disorders was spreading, two Italian researchers wrote an essay in the Annals of Medicine that called into question the increasing number of gluten sensitive patients. This was the not-so-good news.
“Considerable debate about non-celiac gluten sensitivity has recently surfaced on the Internet, with a sharp increase in forums, patients or patient groups, manufacturers and physicians advocating a gluten-free diet, the essay said. “ Claims seem to increase daily, with no adequate scientific support to back them up.”
Discussion about the existence and extent of gluten sensitivity continues despite growing medical acceptance because there is still no test to specifically detect the condition. Gino Roberto Corazza, MD, a gasteroenterologist and professor of internal medicine at the University of Pavia in Italy, cautioned against making a diagnosis based on patient reports alone because the symptoms, which are often similar to those of celiac disease, are so non-specific.
“We know almost nothing about gluten sensitivity except what patients say they believe about it,” Corazza and Antonia Di Sabatino, MD, wrote.
In an online interview with the Annals of Medicine, Corazza said food intolerances are often a “mere consequence” of a placebo effect. “If a patient believes a food is offensive to him, he will develop symptoms,” Corazza explained. He said doctors have to be able to distinguish between “real and unreal patients in an objective way.”
Corazza said the distinction can be made only by using double blind tests to determine who really has gluten sensitivity. And he predicts that many people tested will not be able to distinguish, via symptoms, when they have eaten a food with gluten. “The placebo effect of the elimination diet is very strong,” he said.
It took a long time for those who are gluten sensitive or intolerant to get any validation from the medical community. Corazza’s comments sound a lot like the reaction those patients got from their doctors for many years. Once celiac disease was ruled out, patients were told a gluten-free diet was unlikely to help and left on their own to figure out what to do next. Frustrated and sometimes desperate, they went gluten-free anyway and reported that their symptoms disappeared.
Then about a year ago, scientists from the center for celiac research found that gluten sensitivity is a bona fide condition, distinct from celiac disease, with its own intestinal response to gluten.
They studied 26 gluten sensitive and 42 celiac disease patients, plus 39 control subjects. Although gluten sensitive patients have the diarrhea, abdominal pain and other symptoms suffered by those with celiac disease, they do not have the damage to the absorbing lining of the small intestine that characterizes the auto-immune disorder.
After a four month gluten-challenge followed by a return to the gluten-free diet, symptoms in all the gluten sensitive participants resolved in a few days and did not return for a follow-up period of four years.
Researchers found differences between celiac disease and gluten sensitivity in intestinal permeability and genes regulating the immune response in the gut. (Intestinal permeability is the ability of the mucosal layer of the digestive tract to prevent bacteria, antigens, and undigested food proteins from seeping through the gastro-intestinal barrier. Those who have celiac disease often have a high degree of permeability, sometimes called a leaky gut, but the study found that was not the case in those who are gluten sensitive.)
The study documented, for the first time, the genes and sequence of reactions in the small intestine possibly associated with gluten sensitivity, Fasano said. Though specific tests have not yet been developed, the hope is that results of the study could eventually lead to one that could diagnose gluten sensitivity. About six percent of the US population, or about 18 million people, have gluten sensitivity, according to the celiac center, compared to 1 percent who have celiac disease.
Despite skepticism about the extent of gluten sensitivity, Corazza said he thinks it is a real condition that can be diagnosed as long as the double blind challenge is part of the process. And he called for additional studies to improve understanding of the condition eventually leading to better testing.
That’s where he finds common ground with other experts who acknowledge that there is still a lot we don’t know about gluten sensitivity.