A New Diet Villain

About six years ago, Diane and Jim McConnell and their son, James Jr., 11, embarked on a dramatic diet change. They decided to give up foods containing gluten, a protein found in wheat, rye and barley. Sticking to the regimen is no easy feat—gluten is ubiquitous in the American diet, as well as in other nonfood products. Not only is it in almost every kind of commercially baked good and pasta, it's even in medications, lipsticks and Play-Doh.

Why take such a life-changing step? It all started when James Jr. began suffering from chronic constipation. "Sometimes I couldn't play with my friends because I was hurting so bad," he says. His condition baffled doctors, who initially prescribed laxatives. He stopped growing and started losing weight. Finally, doctors diagnosed his condition as celiac disease, an autoimmune disorder of the small intestine that's caused by a reaction to the gluten protein gliadin. The only treatment is a gluten-free diet. Bye-bye, regular pizza and birthday cake.

For James McConnell and the estimated 3 million other Americans with celiac disease, staying away from gluten is a fact of life if they want to prevent long-term intestinal damage and the myriad digestive discomforts that come with the disease. But they're not the only ones avoiding this common protein. Gluten has become the new diet villain. Over the past year, manufacturers in the United States have sold more than $2 billion worth of products with "gluten-free" claims, according to the Nielsen Co. Devotees of the diet include parents of children with attention-deficit hyperactivity disorder (ADHD) and autism, pregnant women, people with allergies and others who say they simply feel better on a gluten-free diet. Some 15 million to 30 million Americans are buying gluten-free products, says registered dietitian Cynthia Kupper, executive director of the Gluten Intolerance Group. "It's a much bigger market than just the celiac population."

High-profile abstainers are adding to the hype. During her 21-day cleanse this summer, Oprah Winfrey avoided gluten. (She followed the advice found in former model Kathy Freston's book "Quantum Wellness," which urges people to eliminate sources of toxins and allergens.) The actress Jenny McCarthy put her autistic son on a diet free of the protein.

But is this trend more about hype than health? "To my knowledge, celiac disease is the only indication for a gluten-free diet," says gastroenterologist Peter Green, director of the Celiac Disease Center at Columbia University and author of "Celiac Disease: A Hidden Epidemic." "All this gluten intolerance, and using the diet to treat autism, ADHD … there's no documented scientific reason for that at all. However, patients without celiac disease often do notice an improvement in a whole spectrum of gastrointestinal or neurological symptoms when they start a gluten-free diet. But it's not defined by any medical diagnosis."

Even without direct scientific support, many families of autistic kids just say no to the protein anyway. The theory is that kids with autism may have a "leaky gut," which allows some toxins from gluten-containing foods to get into their brains and cause problems, says Peter Bell, executive vice president of Autism Speaks. Bell's own son was a "nonresponder" to the diet. But anecdotally, he says, "as many as 20 to 40 percent of kids seem to respond favorably."

Researchers are sympathetic to, if skeptical of, these claims. "If I was a father of a kid with autism, I would do anything," says Dr. Alessio Fasano, a pediatric gastroenterologist at the University of Maryland. "However, these are the facts: celiac disease is present in roughly 1 percent of the general population and maybe can affect twice as much [of the population] among autistic kids." That means perhaps 2 percent of autistic kids have it "at the most," says Fasano. "I don't think there's too much scientific basis to justify [the] broad intervention of a gluten-free diet." By contrast, 10 percent of people with type 1 diabetes and 10 percent of people with Down syndrome have celiac disease, he says.

Getting a celiac diagnosis in the first place can be complicated. Some 97 percent of those who have it are currently undiagnosed, says Columbia's Green. Typically sufferers see specialists and physicians for 11 years before their condition is recognized and treated. Patients are often misdiagnosed with other problems, such as irritable bowel syndrome, he says. They may come in complaining of fatigue, muscle cramps, missed menstrual periods and depression. Kids with undiagnosed celiac disease may have discolored teeth. The average age of diagnosis is in midlife, when people are 40 to 50 years old. "It was once thought to be a disease of childhood. Actually, it can be triggered at any age, by anything from a surgery to a pregnancy to a cold," says the Gluten Intolerance Group's Kupper. "It's like turning on a light switch."