Those who follow gluten-free diets usually come in one of three types: those who have celiac disease, those who have some other gluten intolerance, and those who have jumped on the gluten-free bandwagon. Now new research is indicating that second type may not exist.
Peter Gibson M.D., professor of gastroenterology at Monash University and director of the GI Unit at the Alfred Hospital in Melbourne, Australia, published a study in 2011 that became the go-to study about non-celiac gluten sensitivity (NCGS). In his work, he stated gluten, which is found in grains like wheat, rye, and barley, can cause gastrointestinal distress in patients without celiac disease.
His work lent credibility to the up-and-coming gluten-free diet craze. Recent surveys show 30 percent of Americans want to eat less gluten, regardless of any gluten intolerance they may have.
Though Gibson’s work helped bring gluten-free diets into the spotlight, he wanted to take another look at his research. His first study gave no indication of what actually caused an adverse reaction to gluten, so he decided to re-do his initial trial under far stricter conditions.
Subjects participating in the study had every meal provided for them for the duration of the study. In addition to closely monitoring what the subjects ate, Gibson had any potential dietary triggers for gastrointestinal symptoms removed from their diets as well. The meals were removed of any lactose, preservatives like benzoates, propionate, sulfites, and nitrites, and fermentable, poorly absorbed short-chain carbohydrates (FODMAPs).
All 37 subjects in the study self-reported gluten insensitivity and were confirmed to not have celiac disease. First, the subjects were given a diet low in FODMAPs for two weeks. Then, they were given one of three diets for a week. The three diets given contained 16 grams of added gluten (high-gluten), 2 grams of added gluten and 14 grams of whey protein isolate (low-gluten), or 16 grams of whey protein isolate (placebo). Every subject had every diet, and none knew which they were eating which week.
Gibson found, after looking at the data, that subjects reported a worsening of their gastrointestinal symptoms to similar degrees whether their diets included gluten or not. He concluded the data indicated a nocebo effect. The subjects reported the symptoms because they expected the reaction, not because the food they ate caused the symptoms.
Because of this, Gibson reversed his stance from his original study saying, “In contrast to our first study … we could find absolutely no specific response to gluten.”