Finding the right cheese — that's what gave Shannon Nowak the most trouble.
"I know, it's just grilled cheese," said the Rochester, Mich., mother whose family has moved toward a gluten-free, casein-free diet. "But we went through six or seven months without grilled cheese sandwiches or cheese in the house. You don't realize how much you'll miss it until you can't have it."
A better understanding of celiac disease — a sort of hybrid between a food allergy and intolerance — has given rise to another kind of consumer: one who scans the grocery store shelves for "gluten-free" products.
Someone with celiac disease can not tolerate the protein found in wheat, rye and barley. The gluten causes an immune response that damages the lining of the small intestine and, in turn, interferes with absorption of nutrients. A person with celiac disease can quickly become malnourished.
A growing crop of gluten-free bakeries and more gluten-free fare in restaurants addresses those people's needs.
Cereal giant General Mills has tweaked cereal, cake and brownie mixes along with its Bisquick products to make them gluten-free. In February, it teamed up with the University of Maryland's Center for Celiac Research to create www.glutenfreely.com, a Web site featuring gluten-free recipes, medical articles, blogs and 400 items in its online store.
"I've been to presentations where it's been claimed that gluten- free is the most significant new (food) product trends in the United States," said Stephen Taylor, a professor of food science and technology at the University of Nebraska-Lincoln and a member of the medical advisory board for the Food Allergy & Anaphylaxis Network.
More good news: More label-savvy consumers not only mean more variety on the shelves, but also better taste, says Justin Hiller , vice president of Hiller's Markets, which carries a variety of allergen- and gluten-free foods.
Taking a bite of gluten-free bread just a few years ago "was like an eating a mix of cardboard and chalk," he said. "Now it's delicious. You can get it in white. You can get it in wheat. You can get it in multigrain and ciabatta."
Still, like many families with diets restricted by food allergies, sensitivities or personal preference, the Nowaks found that it's getting easier to go grocery shopping these days.
Food labeling is becoming more understandable, partly because federal law now mandates that the most common allergens be clearly listed.
It's good business, too.
Approximately 3 million children in the U.S., or about 4 percent, were reported to have a food allergy in 2007 — a jump of 18 percent over the preceding decade, according to a 2009 report by the American Academy of Pediatrics.
For those with food allergies, a bite of the wrong thing — even a touch of it on their skin — can trigger a violent, life-threatening immune response known as anaphylaxis that swells the lips, face, tongue and throat and cuts off breathing.
Such allergies cause 300,000 trips to emergency departments and physician offices, 2,000 hospitalizations and 150 deaths each year, according to the National Institute of Allergy and Infectious Disease, or NIAID.
Even a bowl of vanilla ice cream can be scary if you're allergic to nuts.
"So they make rocky road ice cream, and they hose it (the equipment) down. The next run is vanilla, but it could have trace amounts (of nuts) in the first few cartons," said Carol Finkelstein of Orchard Lake, Mich. Her son Ben, 9, is allergic to milk, sesame, tree nuts and latex.
"It's a game of Russian roulette," she said. "How lucky do you feel today?"
The issue sparked headlines in Florida last month when an elementary school — trying to protect one child with a peanut allergy — began mandating hand-washing each time students entered the classroom. It also ordered mouth-rinsing as soon as students arrived at school and after lunch. Snacks in the classroom were banned. A peanut-sniffing dog was brought on-site.
According to Finkelstein, the school went too far. In fact, after parents protested, it eased some of the rules.
But all of this underscores that the country is still trying balance several things: educating those with allergies about how to protect themselves, training schools in proper emergency intervention during an attack and asking for understanding from others, she said.
Beyond allergies, there is a growing understanding of food sensitivities. This intolerance may not cause the violent immune response of a food allergy, but it can lead to other serious problems, especially with digestion.
High fructose corn syrup, a ubiquitous ingredient in processed food, sends pains into Libby Lee's abdomen that has the 12-year-old doubled over and vomiting violently.
That means certain pizzas or ice cream at a sleepover used to land her in the emergency room: "My stomach kind of feels like there's a knife in it," said the Howell, Mich., seventh-grader.
Combined, as many as 15 percent of the U.S. population has a food allergy or sensitivity, said Dr. James Li, chairman of the Allergic Diseases in the Department of Internal Medicine at Rochester-based Mayo Clinic.
In December, the NIAID released the first comprehensive federal guidelines to diagnosing food allergies. Drawing from research and 34 organizations and agencies, the report offers doctors a "best practices" guide to food allergies and helping patients change their diets to avoid problems.
It's not clear how the 58-page report will change the prevalence of allergies and sensitivities, said Dr. Milind Pansare, a specialist in allergy immunology Children's Hospital of Michigan.
Some patients might learn that their self-diagnosed food allergies really aren't, and others might be diagnosed with previously undetected allergies.
Whatever the change in numbers, the report boosts awareness. That's critical because there's no cure now for food allergies, Pansare said.
The best medical help now, he said, "is about educating families on how to avoid allergens."
And that creates a valuable consumer niche.
In Howell recently, Libby's mother, Sue Lee, returned from the grocery store, thrilled with a new bottle of Hunt's ketchup. Hunt's, a ConAgra food brand, has replaced high fructose corn syrup with sugar.
Already used to scanning the fine print on any food item brought into the house, Sue Lee said that large labels like the "No High Fructose Corn Syrup" banner on the Hunt's condiment are an added convenience that means they're more likely to end up in the shopping cart.
In the case of the ketchup, Hunt's now will be slathered on Libby's french fries, hot dogs and chicken strips.
Libby laughed: "I'm just a kid. That's the kind of stuff I eat and it needs ketchup."
Shannon Nowak, the Rochester mom who longed for a good grilled cheese, doesn't have diagnosed allergies or sensitivities. But she's among those who believe that a diet free of certain ingredients can improve their health.
She and her husband, Timothy, chose a gluten-free and casein-free diet for their son, David, 9, who is autistic. Though there's no conclusive evidence that the diet helps, some believe that avoiding gluten has helped calm some hyper-sensitive children because doing so might ease undiagnosed gastrointestinal problems.
Nowak she she's been surprised at how many tasty products she has found, including a cheddar cheese that is soy-, dairy-, egg- and gluten-free and — as far as Nowak is concerned — "just thrilling."
Allergies affect about 12 million Americans. The body's immune response is triggered as if otherwise harmless substances, including food, are a threat. Sme people produce a specific type of antibody called immunoglobulin E (IgE), which binds to food and triggers the release of chemicals such as histamine. In severe cases, that leads to life-threatening anaphylaxis.
Eight foods account for 90 percent of all food-allergic reactions: milk, eggs, peanuts, tree nuts, fish, shellfish, wheat and soy.
Food intolerance and sensitivity often affect digestion and can be serious as well. Among those that cause problems: lactose (the sugar found in most milk and milk products), monosodium glutamate (MSG), sulfites and other food additives that enhance color, taste or protect against the growth of microbes.