Gluten, a sticky protein found in wheat, barley, and other grains, is our most notorious food villain. It gets blamed for intestinal problems, cognitive and mood difficulties, joint pain, and depression. Last year, almost thirty per cent of Americans said, in a nationwide poll, that they wanted to reduce or eliminate the amount of gluten in their diet. Sales of gluten-free products totalled more than ten billion dollars in 2013, and are forecasted to rise another five billion in the next two years. Popular diet and nutrition books, like “Wheat Belly” and “Grain Brain,” argue that we should just give up eating gluten—and wheat—altogether.
For roughly one per cent of the population—about thirty million Americans—the advice may be sound. For these people, gluten causes the body’s immune system to attack various organs, an ailment known as celiac disease. Twenty years ago, many researchers were skeptical about celiac disease; most now agree that it is real and can be diagnosed through biopsies and blood tests. But scientists remain skeptical of claims made about non-celiac gluten sensitivity, or NCGS, which is purported to cause physical, emotional, or cognitive problems. A significant portion of gluten-free products (food, but also sunscreens, soaps, and even medicines) are sold to NCGS patients.
There are no tests for the condition, but, over the past five years, researchers, doctors (and a few celebrities) have proposed NCGS as an explanation for myriad health concerns, and it’s become an increasingly common diagnosis. Alessio Fasano, a gastroenterologist at Massachusetts General Hospital, in Boston, estimates that as much as six per cent of the population, and perhaps more, has NCGS. By contrast, Peter Gibson, a gastroenterologist at Monash University, in Australia, thinks the number is less than half of one per cent.
A study Gibson published last summer suggests that, when it comes to gut distress, gluten is getting a bad rap. The study focussed on thirty-seven people who identified themselves as having both NCGS and irritable bowel syndrome (IBS), an ailment characterized by a range of gut issues, including diarrhea or constipation, bloating, and stomach pain. The subjects all said that they felt better when they avoided gluten. To test whether the protein was really to blame, Gibson put them on one of three diets: gluten-free, low-gluten, and high-gluten. Each diet consisted of the same foods; the only difference was the amount of gluten.
All three regimens contained very little of another dietary problem child, the carbohydrate known as FODMAP (Fermentable, Oligo-, Di-, Mono-saccharides, and Polyols). Many humans have a hard time digesting FODMAPs, which are found in many foods—among them wheat, apples, artichokes, onions, milk, mushrooms, and mangoes. In recent years, some nutrition scientists have come to suspect that FODMAPs are a key culprit in IBS and other gut problems. RemovingFODMAPs from Gibson’s study diet ensured that gluten was the only variable. Each subject spent a week eating meals from each category, while undergoing tests and keeping a daily symptom diary. It turned out that gluten seemed to have no measurable harmful effects.
“We are convinced that gluten was not the cause of their gut issues,” Gibson said. He suspects that FODMAPs provoke far more intestinal distress than gluten; around seventy per cent of the IBS patients in his clinic who try a low-FODMAP diet see significant improvement. So why did the study’s participants (and, by extension, millions of other people) think that they had NCGS? It may be that people are right to insist that wheat makes them feel bad but wrong about which molecule is to blame: FODMAPs, not gluten, might trigger their intestinal turmoil.
For roughly one per cent of the population—about thirty million Americans—the advice may be sound. For these people, gluten causes the body’s immune system to attack various organs, an ailment known as celiac disease. Twenty years ago, many researchers were skeptical about celiac disease; most now agree that it is real and can be diagnosed through biopsies and blood tests. But scientists remain skeptical of claims made about non-celiac gluten sensitivity, or NCGS, which is purported to cause physical, emotional, or cognitive problems. A significant portion of gluten-free products (food, but also sunscreens, soaps, and even medicines) are sold to NCGS patients.There are no tests for the condition, but, over the past five years, researchers, doctors (and a few celebrities) have proposed NCGS as an explanation for myriad health concerns, and it’s become an increasingly common diagnosis. Alessio Fasano, a gastroenterologist at Massachusetts General Hospital, in Boston, estimates that as much as six per cent of the population, and perhaps more, has NCGS. By contrast, Peter Gibson, a gastroenterologist at Monash University, in Australia, thinks the number is less than half of one per cent.
A study Gibson published last summer suggests that, when it comes to gut distress, gluten is getting a bad rap. The study focussed on thirty-seven people who identified themselves as having both NCGS and irritable bowel syndrome (IBS), an ailment characterized by a range of gut issues, including diarrhea or constipation, bloating, and stomach pain. The subjects all said that they felt better when they avoided gluten. To test whether the protein was really to blame, Gibson put them on one of three diets: gluten-free, low-gluten, and high-gluten. Each diet consisted of the same foods; the only difference was the amount of gluten.
All three regimens contained very little of another dietary problem child, the carbohydrate known as FODMAP (Fermentable, Oligo-, Di-, Mono-saccharides, and Polyols). Many humans have a hard time digesting FODMAPs, which are found in many foods—among them wheat, apples, artichokes, onions, milk, mushrooms, and mangoes. In recent years, some nutrition scientists have come to suspect that FODMAPs are a key culprit in IBS and other gut problems. RemovingFODMAPs from Gibson’s study diet ensured that gluten was the only variable. Each subject spent a week eating meals from each category, while undergoing tests and keeping a daily symptom diary. It turned out that gluten seemed to have no measurable harmful effects.
“We are convinced that gluten was not the cause of their gut issues,” Gibson said. He suspects that FODMAPs provoke far more intestinal distress than gluten; around seventy per cent of the IBS patients in his clinic who try a low-FODMAP diet see significant improvement. So why did the study’s participants (and, by extension, millions of other people) think that they had NCGS? It may be that people are right to insist that wheat makes them feel bad but wrong about which molecule is to blame: FODMAPs, not gluten, might trigger their intestinal turmoil.
by David Kohn, New Yorker | Read more:
Image: Martin Parr/Magnum
