Wheat gets a bad rap in pop culture these days. It’s been blamed for everything from ‘wheat belly’ to ‘grain brain.’ One major culprit for the bruhaha is gluten, a protein present in a number of grains, including all kinds of wheat, rye, barley and ancient grains like spelt and farro. A small percentage of the American population, perhaps one to two percent, have celiac disease – an autoimmune form of gluten intolerance. An estimated 0.2-0.4 percent of the population don’t have celiac disease but do have some form of wheat allergy. And some experts suggest up to six percent of the population also suffers from a condition know ambiguously as non-celiac gluten sensitivity, or NCGS, but new studies are calling this estimate into question.
The increase in reported NCGS cases can be linked back to a double-blinded, randomized, and placebo-controlled study conducted in 2011 by researcher Peter Gibson, a professor of gastroenterology at Monash University in Melbourne, Australia. Gibson concluded from his study that gluten did indeed trigger gastrointestinal distress in patients without celiac disease. The report helped spur the demand for gluten-free products, resulting in a meteoric rise in sales of G-Free products to more than $15 billion in 2016.
But something troubled Gibson. He hadn’t found any specific reason that gluten should be triggering such reactions in his patients. Being a true scientist, Gibson went back to the drawing board and conducted another, more thorough, more rigorous, study.
Gibson discovered that following each treatment diet, subjects reported gastrointestinal symptoms including pain, bloating, nausea, and gas, regardless of whether the treatment diet included gluten or not. The results were the same, even when the the identical, non-gluten diet was served throughout the study. Gibson credited the reported symptoms to the so-called “nocebo effect,” the same reaction that prompts some people to get sick from wind turbines or cell phones. Since the study subjects were reporting gastrointestinal distress without any apparent physical cause, Gibson concluded that gluten wasn't the culprit. Instead, the cause appeared to be psychological. Participants expected the diets to make them sick, so they felt sick.
In a startling reversal, Gibson declared, “In contrast to our first study… we could find absolutely no specific response to gluten."
There are a number of triggers for gastrointestinal distress, and gluten may only be responsible in a tiny percentage of cases. Gibson’s study and others like it indicate the rise in non-celiac gluten sensitivity may be driven more by consumers and commercial interests, than quality scientific research.