At the Whole Foods Market in El Segundo, Calif., two women stand scanning a refrigerator case filled with packages of gluten-free food - carrot cake, rice flour bread, scones, ginger cookies, pecan pie and chocolate chip muffins.

Judy Beckett, a retired educator, was diagnosed with celiac disease two years ago: Her gut cannot tolerate gluten, and switching to these foods has improved her digestion and quality of life. Claudia Lopez, a housekeeper and mother of four, is looking for gluten-free food for herself and her family. She recently switched to it at the urging of a health expert she heard on Spanish radio.

Beckett and Lopez have plenty of company as more and more consumers embrace the gluten-free trend. Users run the gamut: There are people like Beckett with celiac disease who must be on the diet; others who believe the diet can alleviate chronic intestinal complaints and boost energy; still others who believe the gluten-free diet might help in the treatment of autism and a host of other disorders, including schizophrenia, chronic fatigue, multiple sclerosis, attention deficit disorder, migraine and even fertility problems.

And some people are trying the diet simply because they've heard it is healthful.

"A lot of people are going gluten-free … but they really don't know why," says Suzy Badaracco, president of Culinary Tides, a company that forecasts food trends. "It's just like, 'Quick, it's gluten-free, it must be good!' "

It was full-speed ahead for gluten-free foods at this year's Natural Products Expo West, held in March at the Anaheim Convention Center in Orange County, Calif. Attendees at the event - truly the Super Bowl of natural food shows - swarmed around counters featuring gluten-free breads, pasta, steaming pot pies, brownies, warm muffins, cosmetics and even dog treats.

(One exhibitor even advertised a flavored water as gluten-free - cheerfully admitting that, yes, water is naturally gluten-free, but what the heck.)

According to a March 2007 survey by the market research company Mintel, 8 percent of the U.S. population look for gluten-free products when they shop. Nielsen Co., which tracks gluten-free food in U.S. grocery, drug and mass merchandiser stores (excluding Wal-Mart), reports that the gluten-free sector increased 20 percent in the 12-month period ending June 14, to $1.75 billion from $1.46 billion a year ago.

The number of choices also is expanding. In 2007, 700 new gluten-free products were launched in the United States, up from 214 in 2004, according to Mintel. Consumers of gluten-free products can wander down the aisles of their local health food store - in some cases their local supermarket - and choose from an array of gluten-free pastas, cake mixes, waffles, bagels, pizzas, cookies, baby food, even beer and cosmetics. Mintel projects a 15 percent to 25 percent annual growth rate for gluten-free foods over the next few years.

Gluten-free food manufacturers can thank growing awareness of celiac disease, also referred to as celiac sprue, for putting gluten on the map. People with celiac disease experience a severe immune reaction to gluten - a set of proteins in wheat, rye and barley - that interferes with the absorption of iron, folate, calcium and fat-soluble vitamins. The disease can cause serious gastrointestinal symptoms and weight loss and has been linked to osteoporosis, anemia, Type 1 diabetes and autoimmune thyroid disease, says Shelley Case, a celiac researcher, registered dietitian and author of the book "Gluten-Free Diet: A Comprehensive Resource Guide."

Even very small amounts of gluten can spark an inflammatory reaction in celiac patients, Case says.

Until recently, celiac disease was thought to be extremely rare in the United States, says Dr. Alessio Fasano, medical director of the Center for Celiac Research at the University of Maryland. In 2003, there were 40,000 diagnosed cases. Then the center published an epidemiological study estimating that about 2.5 million people in the United States had the disease. Shortly thereafter, the National Institutes of Health boosted the estimate to 3 million, igniting a flurry of business investments in gluten-free foods.

Because of the severity of symptoms and difficulty of preparing gluten-free foods, after a child is diagnosed with celiac disease, parents often put the entire family on the diet, further expanding the market.

Gluten's ubiquity makes it difficult to eliminate entirely. Found in pasta, crackers, cereal, breads and other baked goods, gluten also lurks in less obvious places such as malt vinegar, soy sauce, breaded meats, many flavorings and emulsifiers, beer, gin, whiskey and rye, and gravy and sauces thickened with flour. Ten years ago, celiac patients struggled with meals and menu planning. When gluten-free foods began landing in stores, celiac patients snapped them up.

Parents of children with autism also are snapping them up. Diets that eliminate gluten and/or casein are the most common alternative treatments tried for children with so-called autistic spectrum disorders, says Dr. George Christison, a professor of psychiatry at Southern California's Loma Linda University School of Medicine and parent of a child with autism.

"The medical literature to date contains no clinical trials of adequate size or design rigor to provide clear evidence to say either that these diets do work or … that they do not work," he says. But after sifting through the stories he's heard from parents, Christison thinks the diet indeed might benefit a subgroup of children.

And in the absence of formal evidence, parents are forced to arrive at their own conclusions, and many opt to try the diet.

"No parent of a child on the autism spectrum wants to look back when the child is grown and say, 'If only we had tried … ' " Christison says.

Another group embracing gluten-free foods is people who do not have celiac disease but have gastrointestinal problems that improve when they go on a gluten-free diet. In so-called "gluten sensitivity," there is an immune response or associated condition even though the patient might not have the small-intestine findings on a biopsy to meet the criteria for celiac disease, says Dr. Eric Esrailian, director of general gastroenterology at the University of California, Los Angeles' David Geffen School of Medicine. "Gluten intolerance," Esrailian says, refers more to the symptoms a person feels, similar to the term lactose intolerance. No one knows how many people truly fall in these two categories, he adds.

Another group fueling the boom is the celiac self-diagnoser. "(We see) a lot of patients who have some nonspecific gastrointestinal symptoms," Esrailian says, "who have read about celiac disease on the Internet or heard about it from a friend and have made kind of a self-diagnosis." This can cause unnecessary worry, dietary restrictions and expense, he says.

"A lot of folks say that when they eat gluten-rich foods, they feel a little sluggish," adds Daniel Fabricant, vice president of scientific and regulatory affairs for the Natural Products Association, a Washington, D.C.-based trade association. "Now - is it the gluten or the refined carbohydrate?"

Fifty-five-year-old Debra Green of Los Angeles went off gluten and a number of other foods more than a year ago at the suggestion of Dr. Mark Hyman, a family practice physician and nutrition guru who has written several books on metabolism and weight loss.

Although Hyman determined that Green didn't have celiac disease, he did attribute her indigestion and heartburn to several food sensitivities. The retired TV executive says that since going on the gluten-free diet she has never felt better. "All my ailments went away," she says. "No more heartburn. No more Nexium. My desire for sweets went away. Even my Achilles tendon, which hurts me, stopped hurting."

But people who elect to put themselves on a gluten-free diet without consulting a physician might be creating problems for themselves in two ways.

For one thing, it's difficult to diagnose celiac disease in a person who has been on a strict gluten-free diet for a long time, Esrailian says. "The diet can make the small intestinal inflammation less obvious on biopsy," he explains, and affect the blood test.

And there are broader concerns. Some dietitians worry about the long-term effects of a strict gluten-free diet on people who don't need to be on it, because in avoiding foods with gluten, people could give themselves nutritional deficiencies. Those who elect to go on the diet need to ensure that they get adequate amounts of B vitamins, particularly folic acid, Badaracco says.

From Esrailian's point of view, a good effect of the current fascination with gluten in food is that it has created more awareness of celiac disease.

But many people acknowledge that what started as a quirky health kick might be out of hand. "If you just Google the silly thing, there's all sorts of dietitians and medical professionals against it," Badaracco says. "They're just not organized yet to (band together and) say, 'You know what? This is ridiculous.' "

A question of taste

Anyone who ate gluten-free food five or 10 years ago understandably might opt to avoid such food forever after. In the old days, "We used to joke that when you got the food, you didn't know if you were supposed to eat the box or the contents," says Dr. Alessio Fasano, medical director of the Center for Celiac Research at the University of Maryland.

The taste and texture were pretty bad, agrees Scott Mandell, chief executive and co-founder of Enjoy Life Natural Brands, which makes gluten-free and allergy-friendly foods. "They gave a very gluten-free taste, which means kind of a mealy and bland, crumbly taste," he says. "They didn't give a good mouth-feel. If you ate a cookie, you didn't want another one."

That's because gluten plays a key role in providing structure to baked goods. During cooking, proteins in gluten create a sub-microscopic network that traps gas bubbles and adds viscosity and elasticity to the mix. When the product is heated, the moisture evaporates and the gluten becomes rigid, setting texture and structure.

Some of the old gluten foods weren't even particularly healthful. "Typically, gluten-free foods have been made with refined gluten-free products, including white rice flour, tapioca starch, corn starch and potato starch," says Shelley Case, a registered dietitian and author of "Gluten-Free Diet: A Comprehensive Resource Guide." "They added a lot of fat and sugar to make it taste palatable and stick together, so the food wasn't very good for you."

But in the last few years, gluten-free foods have gotten tastier and more healthful.

Companies specializing in gluten-free foods are incorporating a wide variety of ingredients, often milled into flour to improve the products' flavor and nutritional content, including amaranth, quinoa, garbanzo beans, navy beans, fava beans, buckwheat, almonds, hazelnut, millet, brown rice, sorghum, flax and even mesquite pods and Indian rice grass.

Some products have been developed by small family ventures, often parents of children with celiac disease or others who suffer from the disorder. Finding few ready-made gluten-free foods in the grocery store, they began experimenting at home and spun off their recipes into a cottage industry.

Single mom Shari Cole of Thousand Oaks, Calif., for example, two years ago co-launched a line of gluten-free foods, Gluten Free & Fabulous, after struggling to find tasty food for her daughter, who is mildly autistic.

"Some people laughed at us, saying that (gluten-free food) was a fad," Cole says. "But we got sick of eating bad food that tasted like cardboard." Sales have quadrupled in the last year, she says. "We recently got a nice order from Dubai."

Some of the new offerings have gotten a boost from an unexpected source: a current fascination with ancient grains - such as amaranth, quinoa and teff. These don't have the gluten proteins that trigger celiac disease, food trends forecaster Suzy Badaracco says. "So if you've got a product with ancient grains, if you're smart, you tie it into both trends - gluten-free and ancient grains. It's a double whammy."

Where to find the goods

Saying goodbye to gluten? Gluten-free products can be purchased through many online distributors, often small mom-and-pop operations. The Celiac Disease Foundation Web site includes an extensive list of gluten-free food manufacturers at http://celiac.org/lifestyle/grocery.php

Click on the link for suggested sources.

Health food stores are an excellent place to start. Whole Foods Market carries a broad selection and has its own dedicated baking facility. This is important because if the same equipment is used to make foods with and without gluten, the substance can find its way into both types of product.

More conventional supermarkets are getting into the gluten-free act as well. Chains that carry gluten-free foods include some Bristol Farms, Trader Joe's, Albertsons, Vons, Ralphs, Food 4 Less, Wal-Mart and Sam's Club.