This article appeared in the Autumn 2005 edition of Celiac.coms Scott-Free Newsletter.
Celiac.com 01/11/2006 - There is an abundance of stories about people who begin a gluten-free diet, find that they feel better then decide they want a firm diagnosis of celiac disease. They are facing several problems. First, they may be gluten sensitive without the intestinal lesion of celiac disease. This is very likely since about twelve percent of the population is gluten sensitive, but only a little more than one percent of the general population has celiac disease. Another problem faced by gluten-free individuals who want a diagnosis is that it can take more than five years after returning to a regular gluten-containing diet before the characteristic damage of celiac disease can be seen on a biopsy1. Simply put, after beginning a gluten-free diet, only a positive biopsy is meaningful. A negative biopsy does not rule out celiac disease.
A variety of opinions have been offered regarding how much gluten, for how long, should result in a definitive biopsy. The reality is that no such recommendation is consistent with the medical literature1-4. Some people with celiac disease will experience a return of intestinal damage within a few weeks of consuming relatively small amounts of gluten. Such brief challenges are valuable for these individuals. However, many people with celiac disease or dermatitis herpetiformis will require much larger doses of gluten, over much longer periods, to induce characteristic lesions on the intestinal wall. Unfortunately for these latter individuals, a negative biopsy after a brief gluten challenge can, and often is, misinterpreted as having ruled out celiac disease. Blood tests can compound this problem. If, as seems likely, celiac patients who are slow to relapse are also the ones who develop milder intestinal lesions, they are the very celiac patients for whom blood tests are very unreliable5. Claims to have ruled out celiac disease based on brief challenges with small quantities of gluten is a mistake that could lead to serious, even deadly, consequences.
We may forget that gluten consumption by a person with celiac disease can lead to deadly cancers and a variety of debilitating autoimmune diseases. Any recommendation of a gluten challenge should be accompanied by a clear warning that the process may overlook many cases of celiac disease. The absence of such warnings is inexcusable.
And what about non-celiac gluten sensitivity? The absence of an intestinal lesion does not rule out gluten induced damage to other tissues, organs, and systems. Evidence and research-based information in this area is sadly lacking but we do know that undigested or partly digested gliadin can damage a wide range of human cells6. Thus, one need only be consuming gluten and experience increased intestinal permeability for gluten-induced damage to be a factor in an almost infinite number of ailments.
There are several partial answers to this problem. One, which Ive raised before, is to employ Dr. Michael N. Marshs rectal challenge for the diagnosis of celiac disease, particularly when the individual has already begun a gluten-free diet. This test permits a definitive diagnosis of celiac disease for up to six months after beginning a gluten-free diet. That would catch a great number of celiac patients who have found relief through a gluten-free diet and now want a diagnosis. Another piece of this puzzle is to test for IgG anti-gliadin antibodies. Although these antibodies are considered "non-specific," they inarguably identify an immune response to one of the most common foods in a regular North American diet. Although these individuals may experience improved wellness on a gluten-free diet, we just dont know enough about non-celiac gluten sensitivity to do more than recommend that they continue on this diet since it makes them feel better.