The word “gluten” is often misunderstood as being synonymous with wheat. Actually, gluten refers to two different proteins: gliadin and glutenin. It is the main structural component of wheat, but these protein equivalents are also found in rye and barley. There are several proteins found within wheat, of which gliadin and glutenin are two.1 Basically, gluten proteins give bread its structure and chewy texture, and are only two of many wheat proteins.
Since the evolution of agriculture 10,000 years ago, gluten- containing wheat products have been making their way into the daily diets of families and individuals across the world, with an adult in wheat consuming countries consuming an average of 150- 250 grams of wheat flour per day, with an average of 10- 20 grams of gluten.2
Within recent years, a wide spectrum of gluten- related disorders have surfaced all over the world; namely, Celiac Disease, wheat allergy, and finally the commonly reported Non- Celiac Gluten Sensitivity (NCGS), more popularly known as gluten sensitivity. Many of the symptoms for these conditions are similar in clinical presentation, which can create confusion among those experiencing symptoms, as well as the treating physicians. Because NCWS is largely a diagnosis of exclusion, it is important to understand what it is NOT.
Celiac Disease is an intestinal pathology characterized by a chronic autoimmune digestive disorder triggered by the ingestion of gluten, resulting in inflammation of the small intestine. It is one of the most common disorders in Europe, North and South America, and Australia, and prevalence is rising in Asian countries, where wheat is becoming a preferred staple, replacing rice- based carbohydrate choices. Both Celiac Disease and gluten NCWS are characterized by intra- intestinal and extra- intestinal symptoms (inside and outside of the intestines); however specific tests are needed to confirm or deny Celiac Disease, where as NCWS cannot be identified by any laboratory biomarkers. When testing for CD, your physician may order a bowel biopsy, serum testing for IgA class antibodies (specific immune system response), and evaluation of clinical symptoms. Symptoms may include chronic diarrhea, anemia, weight loss, and neurological disturbances.1 Separately from gluten sensitivity and wheat allergies, symptoms of Celiac Disease may take days to weeks to manifest.
Wheat allergies are also characterized by immune responses, triggered by the ingestion of wheat, which remain localized to the digestive system. This allergy is present in 0.5 to 1.5% of the population world- wide, and tends to increase with age. Wheat allergy is often confused with Celiac disease; however, because gluten is only one component of wheat, several other proteins within the wheat product could be responsible for the allergic reaction. This partially distinguishes it from CD, where gluten in particular is the problematic component. Also separately from CD, wheat allergies generate different antibody proteins in response to wheat ingestion (IgE).2 Symptoms occur within minutes to hours of ingestion, and can include: swelling, itching or irritation of the mouth or throat hives, itchy rash or swelling of the skin, headache, itchy eyes, difficulty breathing, cramps, nausea or vomiting, diarrhea, and sometimes anaphylaxis (severe allergic reaction).3 Consult your physician when you suspect wheat allergy; the only way to avoid symptoms of wheat allergies and CD is to follow a gluten- free diet.
While there is no definition or testing specific to the condition, “Non- Celiac Gluten Sensitivity,” also known as gluten sensitivity, it is a controversial diagnosis of exclusion, meaning it is diagnosed when autoimmune and allergic mechanisms have been ruled as sources of gluten reactions, and symptoms are reduced or eliminated when following a gluten- free diet. The proposed symptoms of gluten sensitivity are similar to the gastrointestinal discomfort experienced by those with non- inflammatory FODMAP intolerances and CD. However, a debate remains as to whether or not this is a true medical diagnosis.
Gluten- free diets are rapidly growing in popularity, due to perceived health and weight maintenance benefits, amplified by social media, but the claims are poorly supported by the research. One of the major problems with diagnosis is that little is actually known about gluten sensitivity (NCGS) and symptoms are poorly defined, though the concept of its existence is widely popularized. The mechanisms driving symptoms, the minimum amount of gluten proteins needed to trigger symptoms, and whether or not gluten is truly to blame, are all topics of research. In light of recent evidence, it is possible that FODMAPS and psychological influences could play a significant role in a perceived gluten sensitivity.
In 2011, Gibson et al conducted a double- blind randomized control trial which greatly lent to the popularity of the gluten- free advocates. Subjects with Irritable Bowel syndrome, but without Celiac Disease, who normally followed a gluten- free diet, were told to incorporate 2 slices of bread and 1 muffin into their daily diet. Meal contents were not controlled in a laboratory setting, and adherence was tracked by self- report. As opposed to the control group which continued their gluten- free diets, the muffin- eaters reported increased pain, bloating and fatigue overall at 1 week.
Regardless of the reported worsening of symptoms, there were no significant inflammatory reactions observed in the participants as a result; therefore, the mechanism of the symptoms could not be concluded, although Gibson’s study seeks to support the existence of gluten sensitivity.
However, few variables were controlled for, which could have contributed to the results. Additionally, because there are no diagnostic biomarkers indicative of NCGS, and due to the popularity of the popular perceived benefit of a gluten- free diet, psychological influences cannot be excluded as the basis of the results, based on the results of this study. Essentially, when dieters have already concluded that gluten- containing foods are detrimental to one’s health, they may experience physical symptoms upon ingestion, regardless of the absence of physiological biomarkers. Think “mind over matter.”4
Gibson contributed to a second, more tightly controlled study, in 2013. Again, the participants were people who complained of GI disturbances without the presence of Celiac Disease. This time, FODMAPS’s (fructose, lactose, grains and other carbohydrate sources which are difficult for many people to digest) were reduced from participants’ diets to obtain a baseline, and then researchers fed the participants throughout the study to control for interfering variables. Subjects in the experimental group received meals randomly ranging from no gluten (16 grams of whey protein) to low gluten (2 grams of gluten and 14 grams of whey protein), to high gluten content (16 g of gluten), while the placebo group never received a meal containing gluten. Incidentally, subjects in the experimental group reported increase in pain, bloating and nausea whether or not their meals contained gluten; similarly, when reverted back to their baseline non- gluten non- FODMAP diet (unbeknownst to the participants), subjects continued to report an increase in symptoms. Therefore, gluten could not be to blame here, but the results here allude to symptoms caused by the psychological perception of gluten as a GI irritant.5
Researchers noted the more likely possibility that FODMAPS were the major source of gastrointestinal discomfort, as participants noted a reduction in symptoms during the baseline period, where FODMAPS were eliminated.5 Researchers are still working to determine whether or not “gluten sensitivity” truly exists. More research needs to be done to identify possible diagnostic biomarkers to indicate a sensitivity if one exists, as none of the physiological manifestations present in CD are present in candidates for Non- Celiac Gluten Sensitivity. However, the results of Gibson’s 2013 study suggest that those with GI discomfort, perceived as a direct result of gluten sensitivity, may actually benefit from a low FODMAP diet instead.
Many people without CD may lose weight on a gluten- free diet, at least initially, regardless of their “sensitivity” or lack thereof, but this likely isn’t due to the lack of gluten specifically. However, abstaining from grains often results in a lower caloric intake and lower carbohydrate intake, which can both support fat loss. Calorie deficit is likely the contributor to weight loss in this case. However, replacing gluten- containing foods and products with gluten- free replacement products simply means replacing the wheat gluten with another starch, and will less likely result in an overall calorie deficit. There is no dramatic calorie- evaporating magic show when it comes to gluten- free products, (unfortunately, but do invite us to that magic show if you find it). Calories from one are not superior to calories in another in terms of fat loss, so it doesn’t mean you are going to lose body fat when you subtract the gluten. Also note that a “gluten- free” label does not necessarily indicate that it is also wheat free; it simply means that the gluten proteins have been mostly removed from the grain.
While an apparent spectrum of gluten- related disorders can certainly be recognized today, more research still needs to be done to explore the true presence of gluten sensitivity. Similarly, the question can be raised: why are the confirmed diagnoses of Celiac Disease and self- reported incidence of gluten sensitivity rising? While technological advances in food processing are increasing, the consumption is also increasing across the world. See our article on “Gluten Sensitivity and the Rise: Our Search for Answers,” for more on these topics. (*hyperlink to other gluten article*)
Does a gluten- free diet make you feel better? We aren’t trying to say that you should abandon it! But interestingly enough, some of the largest dietary sources of FODMAPs include bread product, and FODMAPS are common GI irritants, especially when eaten in large amounts, and can cause similar symptoms to those associated with gluten sensitivity. Because they are removed when adopting a gluten-free diet, this finding could potentially explain why the millions of people worldwide who go gluten-free feel so much better. If one experiences GI discomfort and suspects a gluten sensitivity, they may want to consider trialing a reduced FODMAP diet first, rather than immediately removing all things gluten and opting for gluten- free products. FODMAPS include foods such as fruits, grains, lentils, beans, dairy, and more.
HOWEVER, just because the research doesn’t currently support the existence of a true medical diagnosis, that doesn’t mean it should stop you from going on with your bad gluten- free self if it makes you feel better.
Dr. Elizabeth Lane, PT, DPT
Nutrition and Wellness Specialist
- Sapone A et al. Spectrum of Gluten- Related Disorders: Consensus on New Nomenclature and Classification. BMC Medicine. 10(13); 2012.
- Schuppan et al. Non- Celiac Wheat Sensitivity: Differential Diagnosis, Triggers, and Implications. Best Practice & Research Clinical Gastroenterology. 29; 2015.
- Wheat Allergy. http://www.mayoclinic.org/diseases-conditions/wheat-allergy/basics/symptoms/con-20031834. Accessed 02/03/16.
- Gibson P et al. Gluten Causes Gastrointestinal Symptoms in Subjects Without Celiac Disease: A Double-Blind Randomized Placebo-Controlled Trial. Am J Gastroenterol. 2011.
- Biesiekierski J et al. No effects of gluten in patients with self-reported non-celiac gluten sensitivity after dietary reduction of fermentable, poorly absorbed, short-chain carbohydrates.” Am J Gastroenterology. 2013.
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