Geoffrey Flolo, a professional clarinetist who also works at a health food store in Virginia, avoids eating wheat, rye, or barley whenever possible. All three grains contain the protein gluten, which he believes is unhealthy for him. A few years ago, his self-imposed restriction meant eating no pizza, no bread, and no doughnuts. Now Flolo eats all those, thanks to the profusion of new gluten-free products.
In not quite 1 percent of Americans, consuming gluten damages the small intestine and impairs its ability to absorb nutrients. For such people, whose condition is known as celiac disease, doctors prescribe a gluten-free diet like Flolo's. But as far as Flolo knows, he doesn't have celiac disease. In fact, surveys show that about 15 to 25 percent of consumers report looking for gluten-free products, apparently far eclipsing the number put on the diet by their doctors, says Cynthia Kupper, a dietician and the executive director of the Gluten Intolerance Group. While there's no firm evidence that the diet is helping them, most nutritionists say there's nothing known to be risky about it either.
For those who have a clear medical need for gluten-free products, the surge in options is a boon. "Gluten-free food used to taste like cardboard," says Nina Glaser, 25, a student at the Maryland Institute College of Art who has celiac disease and has been eating no gluten for six years. Now, she says, tasty options abound. According to the research firm Mintel, the number of newly introduced gluten-free products has skyrocketed from about 135 in 2003 to 832 that debuted in 2008, and the company forecasts steady 15-to-25-percent growth in gluten-free product sales in coming years.
For people like Glaser, the plethora of new products makes adhering to doctor's orders easier. Following a strict gluten-free diet allows their small intestines to recover and significantly extends their lifespan. On a normal diet, they can develop vitamin deficiencies and chronic health problems such as osteoporosis or intestinal cancer.
While awareness of celiac disease is rising, most people who have it—perhaps 95 percent of them—don't realize it. As many as 3 in 4 people with the disease have no noticeable symptoms, says Peter H. R. Green, the director of the Celiac Disease Center at Columbia University. Even people who do have symptoms—often diarrhea, abdominal pain, and bloating—may have a hard time getting diagnosed; the average delay is 11 years, and doctors often misdiagnose celiac disease as irritable bowel syndrome, unrelated anemia, or stress. However, going gluten free without consulting a doctor is discouraged, since it further raises the likelihood of misdiagnosis.
To make matters more complicated, some people who test negative for celiac disease nevertheless seem to feel better when they go gluten free. As much as 15 percent of the population may fit into this category, which doctors call "gluten sensitivity." It's not clear how prevalent gluten sensitivity is among the consumers who opt to go gluten free without consulting a doctor.
Beliefs some advocates have about the diet don't entirely square with medical evidence. It's been said that gluten exacerbates the symptoms of autism, for example, and that dropping it from one's diet can lead to weight loss. An evidence review conducted by the Cochrane Collaboration and published in 2008 found that only two reliable studies have examined gluten and autism, and they involved a mere 35 participants in total. One study found the gluten-free diet had no impact on symptoms of autism, while the other detected a degree of improvement in communication and some decline in social isolation among people on the diet. However, the Cochrane researchers conclude more rigorous research is needed before clinicians can recommend the diet as a treatment.
There's even less evidence that the diet produces weight loss. It's well known among people with celiac disease that a gluten-free diet typically causes weight gain, says Vanessa Maltin, a spokesperson for the National Foundation for Celiac Awareness. Those patients, though, are often underweight to begin with. For healthy people who abstain from gluten, it might come down to what substitute they use. Many gluten-free products have extra sugar or fat mixed into substitute flours such as white rice flour or potato starch to make them more palatable. Yet alternative grains such as quinoa, amaranth, and millet are tasty, packed with healthful nutrients, and underused in American recipes.
Meantime, as gluten-free eating becomes faddish, there's worry that respect for the diet as a medical treatment could founder. "We have to be careful that [the diet's growing popularity] doesn't negate the seriousness of the situation for people with celiac disease," says Carol Shilson, executive director of the Celiac Disease Research Center at the University of Chicago. She has celiac disease, and a tiny piece of bread can produce a rash and stomach pain. It's important that waiters and cooks, she says, are vigilant about making sure her food doesn't get contaminated with even a small amount of gluten.