The case against corn—and corn-based sweeteners—has been made with such vigor that some sensitive souls won't even buy fresh ears at the farmers market. These days, health-conscious consumers are just as wary of gluten—a dietary bogeyman found in wheat (as well as barley and rye) that turns up in a startling array of foodstuffs. According to a report from the market-research group Packaged Facts, sales of gluten-free products in the United States have grown by an average of 28 percent over the past five years and will soon be worth $2.6 billion. In May, Elisabeth Hasselbeck, co-host of ABC's The View, went on a bread-bashing publicity blitz for her best-selling new book, The G-Free Diet: A Gluten-Free Survival Guide. Even America's pastime has turned its back on wheat: Last week, Coors Field introduced the first gluten-free concession stand in Major League Baseball.
The lavishing of attention on wheat alternatives is wonderful news to the sufferers of celiac disease, for whom any amount of dietary gluten can inflame and destroy the lining of the small intestine. (The human gut can't fully process gluten. At best, it's converted into a set of indigestible protein fragments that pass uneventfully through the gastrointestinal tract. If you've got celiac disease, these fragments set off a damaging immune response.) This can show up as diarrhea, vomiting, abdominal pain, skin rash, anemia, fatigue, or osteoporosis—and the long-term prognosis isn't so good, either: Celiac patients have almost twice the normal risk of cancer, and one-third of them suffer from another autoimmune disease, like Type 1 diabetes, lupus, or multiple sclerosis. (They may also be susceptible to schizophrenia.) As far as we know, the only way for people with celiac to stave off these dangers is to eliminate gluten from their diets—entirely and without exception—for the rest of their lives.
But diagnosed celiacs only account for a small fraction of the bloated and still-expanding market for gluten-free products. (In total, the disease affects just 0.75 percent of the population.) The remainder are those consumers who believe, for one reason or another, that gluten is hurting them, too. According to Alessio Fasano, director of the Center for Celiac Research at the University of Maryland and a leading expert on the disease, almost half the people who show up at his clinic are on the gluten-free diet before they've even been tested for celiac. For every patient whose intestinal biopsy turns up positive, he says, nine or 10 more test clean but commit to going G-free all the same.
These patients are described as having "gluten intolerance," a nebulous condition that amounts to something like celiac-lite: They feel pain or discomfort after eating wheat, rye, or barley but lack the hallmark signs of intestinal deterioration. The notion that you can have the symptoms of celiac but not the full-blown disorder is based on the idea, first proposed in 1992, that a person's reaction to gluten can be plotted along a sensitivity spectrum —with celiac patients falling at the most vulnerable extreme. Since there's no way to "prove" a case of gluten-intolerance in the lab, the diagnostic criteria are rather lax. To qualify for the condition, you need only discover (with or without medical supervision) that going "G-free" makes you feel better—in body or mind or spirit.
I'm all for people eating what they want, but lately I've started to wonder how gluten intolerance might relate to a more general anxiety about food. The mere fact that someone who cuts out gluten feels better doesn't mean that he has an autoimmune disease or a wheat allergy or some other medical condition. Any kind of restrictive diet can help alleviate gastrointestinal distress. If you're paying more attention to what you eat, there's a good chance your symptoms will lessen. That's not because gluten or red meat or another food is damaging your small intestine; it's because eating less makes it easier for your gut to recover. Then there's the placebo effect of starting any treatment, which might well address some of the more abstract symptoms of gluten intolerance, like fatigue, mood swings, and depression.
The health benefits of a gluten-free diet might also be a kind of self-fulfilling prophecy. It's well-known that our digestive system adapts its secretions (rather quickly) to whatever we're eating. A prolonged stint on the Atkins diet, for example, can make it harder to digest starchy foods. According to a 2006 study in Journal of the Pancreas, a colony of lab rats subsisting on low-carb, high-fat food pellets ended up with less pancreatic α-amylase, an enzyme that helps break down complex carbohydrates. Now imagine that you've cut out gluten from your diet completely—that means no bread, no cereal, no wheat whatsoever. Chances are you'll have reduced your total intake of carbs, and thus the amount of α-amylase in your gut. In other words, the mere fact of being on a gluten-free diet could make you more sensitive to grains and cereals—which would only reinforce your conviction that you're gluten-intolerant. Slip up for even one meal, and you'll pay the price with indigestion. (Same goes for people who don't eat meat or dairy: A momentary lapse can yield a nasty stomachache.)
The fact that "going G-free" means eating fewer cupcakes and less pasta suggests another source of relief. It is, after all, an elaborate diet—and so delivers all the psychological benefits of controlled eating and self-denial. "Once G-free, you are no longer simply robot-eating bag after bag of pretzels," writes Hasselbeck, in a chapter of her book titled "G-Free and Slim as Can Be!" Gluten intolerance may be a medical condition, but according to Hasselbeck, it's also an approach to eating—like South Beach or Skinny Bitch—that's supposed to make you lose weight and feel good about your body.
Is it a coincidence that the specter of gluten intolerance only emerged in the midst of the low-carb bonanza? In the accompanying graph, I've charted the rate at which major newspapers mentioned "gluten intolerance" or "gluten sensitivity" over the past two decades and compared it with the rate at which they mentioned the "Atkins diet." Both pop-culture trends began to surface about 10 years ago; the Atkins diet peaked in 2004, and gluten intolerance followed a year or two later.