Over the past couple of years, gluten-free has become one of America’s most popular diet trends. Proponents have sworn by it, claiming it relieves  symptoms such as an upset stomach or inflammation they say is caused by eating gluten, a protein mixture that naturally occurs in many wheat and grain-based products.

Gluten-free diets have even been popular among those without celiac disease, a disorder in which one is allergic to gluten. These people — whose condition is commonly referred to as non-celiac gluten sensitivity — claim that removing gluten from their diet has ended the painful symptoms. Yet a recently released study suggests there may not be such a thing as non-celiac gluten sensitivity.

“Gluten sensitivity seems to be possibly something that occurs, but only in a small group of patients,” said Dr. Cesar Fernandez, a Gadsden-based gastroenterologist. “The percentage of these patients is a lot less than what we think they are. The question is, what’s the culprit?”

The study was released by Dr. Peter Gibson, a professor of gastroenterology at Monash University in Melbourne, Australia. Gibson first conducted a study in 2011 that seemed to prove gluten sensitivity in patients without celiac disease.

However, he was unsatisfied with his findings, and last month released the results of an experiment that disproved his earlier test. In the study, Gibson gave a group of 37 non-celiac gluten sensitive patients various dishes containing a lot of gluten, a little gluten and no gluten whatsoever.

All subjects reported having the same symptoms associated with gluten sensitivity, regardless of which dish they ate, suggesting that something else in the food was causing the distress, or that the patients were experiencing a “nocebo effect” — because they thought the food would harm them, it did.

Fernandez said he is not surprised with the experiment’s results, even if it leaves gastroenterologists unsure as to the exact cause of their patients’ gastrointestinal stress. Doctors have long been trying to fully understand the mechanism that causes distress in patients, Fernandez said, and this study is a step in the right direction.

Sylina Haller of White Plains does not have celiac disease, but spent a year on and off gluten-free diets. Although she is no longer on the diet, Haller said she thinks cutting out gluten is beneficial — she claimed to have felt better after a few weeks on the diet. Now that she knows the issues might not be caused by gluten, however, she might try a new approach.

“I’m intrigued,” Haller said. “That will probably have some bearing with what I eat. I probably will do something about it in the future. I think people are looking for a quick fix to feeling bad.”

That is the same thought Fernandez has about patients who are ready to diagnose themselves with gluten sensitivity. The issue could be a combination of a number of causes, including irritable bowel syndrome, or something called fermentable poorly absorbed short-chain carbohydrates, which are found in many of the same foods as gluten.

In fact, Fernandez suggests that perhaps patients should first reduce their sugar intake and improve their overall diet before committing themselves to a potentially expensive and time-consuming gluten-free diet.

“Being on a completely gluten-free diet is actually quite difficult,” he said. “Even people with celiac who have been on the diet for years hate it, and don’t follow it completely. My advice would be to look for the advice of a gastroenterologist before they commit themselves to a gluten-free diet.”