By Myers R. Hurt, M.D., UTMB Department of Family Medicine

Gluten – what exactly is it? Jimmy Kimmel took to the streets with this same inquiry in his late-night sketch “The Pedestrian Question.” 2.8 million views on YouTube show that the world is curious as well – and that the four ultra-fit “gluten-free” individuals he interviews have absolutely no idea what they are avoiding.

Patients ask me at least weekly about each new passing fad diet and this one is no exception. Seemingly more than just a passing glint on the tongue of celebrity doctors of daytime television, the data appears skewed in multiple directions with disciples behind each attestation citing personal example, academic publication, laboratory data, meta-analyses, and various interpretations of data.

As most readers of this publication may already know (unlike Mr. Kimmel’s comedic fodder) gluten is, in fact, a protein composite found in wheat, barley, and rye. From the Latin gluten – meaning glue – gluten is what gives foods elasticity. As such, it is most commonly found in “doughy” foods such as breads and pastas, but it is also commonly found in gravies, sauces, soups, and salad dressings.

At the core of the current gluten-free diet revolution are those who avoid the protein for medical reasons. One percent of the US population – about 3 million people – suffer from celiac disease, an autoimmune disease of the small intestine. In what is primarily an inflammatory reaction, when these individuals ingest gluten, they experience an array of symptoms including but not limited to: abdominal pain, joint pain, skin rashes, and fatigue. Current studies show that an additional six percent – or 18 million more Americans – exhibit signs on a spectrum of “non-celiac gluten sensitivity” (NCGS). These individuals have labs tests that are not consistent with actual celiac disease, but experience similar bloating, constipation, diarrhea, and abdominal pain after consuming gluten.

A recent PubMed search reads like a politician’s Wikipedia page, frequently updated and with powerful studies on both sides of the issue. A few papers are literally from the same authors arriving at two different conclusions. A literature review published in the Journal of the American College of Nutrition recommends labeling a patient with NCGS only after ruling out both celiac disease and wheat allergy with negative serology, histopathology, and IgE-mediated assays. While no specific biomarkers for NCGS could be identified in the examined literature, study subjects in multiple papers reported subjective improvement in both gastrointestinal and non-gastrointestinal symptoms while following gluten-free diets.

Commercially, the two top-selling authors on the subject, Drs. William Davis and David Perlmutter, address gluten in the realms of the gut and brain respectively. Their books, Wheat Belly and Grain Brain, are both #1 New York Times bestsellers. They illustrate the current strain of modern dwarf wheat as a genetically modified and bastardized distant relative to the carbohydrate-rich “whole-grain” wheat of our ancestors with as much as 5 times the original gluten content. This is in addition to the usual processing procedures necessary to produce consumable goods on store shelves.

Dr. Perlmutter, a neurologist, focuses the content of his work on avoiding sugar and processed grain to help prevent neurologic disorders, namely Alzheimer’s, ADHD, depression, and Parkinson’s Disease. In fact, a low-carbohydrate ketogenic diet has been used successfully for decades in the symptomatic treatment of epilepsy in children, and a literature review turns up promising results of ketogenic diets in most neurologic conditions but is sparse when discussing primary prevention in patients without such diagnosed conditions. Dr. Davis takes a similar approach, with an emphasis on the effects of gluten on intestinal pathophysiology, citing peer reviewed reports on proven celiac disease, while extrapolating to the general population as a whole. These call to mind to the discussion surrounding aspirin for prevention of myocardial infarction - significant data surrounding specific populations, and an obvious benefit for secondary prevention, with recommendations on both sides of the issue when dealing with primary prevention.

The most outspoken critics of the two authors offer studies of tribal cultures with incredibly high carbohydrate intake with lean bodies, little to no diabetes, and little to no neurological diseases. They are quick to accuse them of simply repackaging of the Atkins diet - simply diverting caloric intake from refined carbohydrates to animal proteins and fats. Some of the more eloquent cite the Annals of Internal Medicine, Public Library of Science, and British Medical Journal and publications showing correlation of low-carbohydrate diets with higher risk all-cause mortality. Most critics, however, are then quick to promote their own books - some permutation of carbohydrates, fats, and protein in presumably the next trendy ratio or newly discovered superfood.

With all of this attention, gluten-free foods now enjoy a cult-like following. In the current environment of general wellness, farm-to-table, no-carb, slow food, Atkins, low-carb, Paleo, non-GMO, organic, etc., a gluten-free diet fits many molds and hits many high notes. It forces followers to avoid processed foods, avoid most alcohol, and to consume more fruits, vegetables, and lean organic meats. Even the carbohydrates it does allow add a variety of whole grains often missing from the standard American diet – amaranth, quinoa, and millet for example.

Perhaps most responsible for the current popularity, it helps people subjectively “just feel better” and pockets of gluten-free supporters continue to sprout up nationwide through word of mouth. No surprise, but given this increasing demand, both corporations and the government are listening. The FDA is introducing new labeling requirements for gluten-free foods, and the market of gluten-free products is estimated to reach anywhere from $5 to $15 billion dollars in 2016 according to a recent New York Times article. At the end of the day, my advice to all patients includes proper diet and regular exercise. So far, peer review has helped both the Mediterranean and DASH diets to the forefront of cardiac mortality prevention. More research is necessary to include a gluten-free diet in their ranks.

Some of the best advice is usually the most simple – and food author Michael Pollen puts it eloquently: “Eat food. Not too much. Mostly plants.” This is sage advice, and also somehow vaguely gluten-free. Overall, it is a dietary discussion that helps our patients become more mindful of what they are putting into their bodies and I recommend we view this in a positive light. Is it right for some patients? Absolutely. Is it right for everybody? Time will tell.