A recent story on the National Post discussed the waning trend of gluten-free products and gluten diets, in which the market has “peaked” and growth had slowed. Ten years ago, such diets and products were almost unknown. By the end of 2010, sales of gluten-free products had reached more than $2.6 billion and may reach more than $5 billion by 2015, according to the National Foundation for Celiac Awareness. With an increasing number of people claiming themselves to be “gluten-sensitive” or on “gluten-free” diets, are these claims real and do these people actually have a gluten sensitivity? Or is being “gluten-sensitive” a new diet trend like Atkins and Paleo?
Celiac disease is a genetic, auto-immune disease that damages the villi of the small intestine,which is the site where nutrients are absorbed into the bloodstream when gluten is ingested. Gluten is a type of protein found in rye, wheat and barley, which gives bread its chewy texture. It is also found in non-food products, such as lip balm, some pharmaceutical medicines and the glue on the back of stamps and envelopes, according to MedlinePlus.
Celiac disease is just one aspect of gluten sensitivity, affecting 1 out of 133 Americans, or about three million people. Each person reacts differently to the disease, ranging from diarrhea and abdominal pain to irritable bowel syndrome (IBS), especially among children. Yet there are some people who are gluten-sensitive and show no such symptoms. Although there is no current pharmaceutical treatment of celiac disease, adopting a gluten-free diet can prevent the symptoms.
Despite the increased diagnosis of celiac disease and its awareness, about 83 percent of Americans who have the disease are either undiagnosed or misdiagnosed for other conditions, according to NFCA. Sometimes those who claim themselves to be gluten-sensitive do not have celiac disease. Medical professionals call this phenomenon non-celiac gluten sensitivity (NCGS), referring to those who show symptoms of celiac disease without the genetics or biomarkers of the disease.
A report published in the September 2013 issue of Cell & Molecular Immunology stated that NCGS is heterogeneous, meaning that it is caused by multiple factors that differ among each person, such as low intestinal inflammation, changes in gut bacteria and reduced ability to absorb food in the small intestines. The hypothesis is that foods that are rich in “fermentable monosaccharides and polyols” could be the major triggers of NCGS. However, the prevalence of NCGS ranges widely from 0.63 to 6 percent of the American population. The reason why it is difficult to diagnose and identify is because the biomarkers for this disease have not yet been identified. Therefore, it is difficult to treat and identify such gluten sensitivity, which may be real or not. Another publication from the Dutch Journal of Medicine published in the same year found similar conclusions about NCGS, including similarities of symptoms between NCGS with irritable bowel syndrome and the lack of biomarkers to identify NCGS.
Despite the lack of biomarkers and other forms of gluten sensitivity identification, current evidence shows that NCGS could be as real as other gastrointestinal diseases. A British study published in the December 2013 issue of European Journal of Gastroenterology and Hepatology examined 1,002 adults (55 percent women) who were screened for gluten sensitivity. About 13 percent of the sample population were self-reported as having gluten sensitivity with 3.7 percent of them eating a gluten-free diet. About 0.8 percent of them are known to have been diagnosed with celiac disease. This group showed a significantly higher prevalence of having IBS than those without gluten sensitivity. In the secondary part of the study, 200 gluten-sensitive patients were examined. Seven percent had celiac disease while the rest had NCGS. All patients with celiac disease showed biomarkers that indicate the presence of the disease while a little more than half of the NCGS group showed such biomarkers. Researchers concluded that those most of the patients who self-reported to have gluten sensitivity may have “an association with irritable bowel syndrome.”
However, not every physician agrees with the “reality” of NCGS because of the lack of sufficient evidence and skepticism, and not every study showed that NCGS is entirely real. Dr. Peter A. Lipson, who is a practicing internist and teaches at a community hospital in Southeast Michigan, wrote on a blog on ACP Internist that the term “gluten sensitivity” is poorly defined and is often a ” self-diagnosed by someone who feels unwell and then is better when following a “gluten-free” diet. People blame gluten for everything from child behavior and learning problems to chronic pain and fatigue.”
Lipson also mentioned that many of the symptoms of NCGS are “vague and subjective,” and gluten sensitivity diagnoses and treatments are usually patient-driven, which makes each case even more complicated. “Doctors in the office are often confronted by the problem, and patients and doctors both are frustrated by the lack of knowledge.” He added that it is currently unclear how gluten-free or reduced gluten diets might affect people with self-defined gluten sensitivity.
In fact, an Australian study published in Gastroenterology in 2013 showed that Lipson could be right. Researchers from Monash University in Melbourne performed a double-blind crossover trial of 37 subjects with IBS and NCGS with no celiac disease who were self-diagnosed with these diseases. They were randomly assigned to a two-week diet of reduced short-chained carbohydrates, known as FODMAPs, and were then put on a high-gluten or low-gluten diet or placed in a control group in which they ate mostly whey protein for a week. After the week, everyone went through a “washout period” of at least two weeks before researchers assessed their serum and fecal markers that indicate inflammation, auto-immune activation or indices of fatigue.
Researchers found that symptoms among all subjects had significantly improved during the reduced FODMAP diet. However, only eight percent of the participants who consumed any level of gluten showed any gluten-specific effects. There were also “no diet-specific changes in any biomarker.” In their conclusion, they found “no evidence of specific or dose-dependent effects of gluten in patients with NCGS placed on diets low in FODMAPs.”
While research continues to determine whether gluten sensitivity in non-celiac disease cases are real or not, there is still a lack of strong evidence to determine the identity of NCGS. Even the term itself could confuse the public and health professionals. “NCGS is complicated because there is much more going on in wheat grains than just gluten,” Angelique Crandall, a registered dietitian practicing in Albuquerque, New Mexico, commented during an online interview, “People may be reacting to other components of the grain — WGA, AMI, FODMAPS, etc. In short, ‘NCGS’ may actually be a misnomer, but the problem with wheat is still very real.”
By Nick Ng
Interview with Angelique Crandall, M.S., R.D.
Dutch Journal of Medicine
Cell & Molecular Immunology
European Journal of Gastroenterology and Hepatology