NEW YORK - The number of gluten-free products is increasing at a rapid clip these days: beer, pizza, pasta, bagels, cake mixes, waffles, gum and even pet food, the New York Daily News reports. The main reason for the rise of gluten-free products is that more Americans are being diagnosed with celiac disease, which means they avoid flour or any foods containing gluten. Gluten is commonly found in cereals, soy sauce and beer, among other foods.

Gluten-free products sales jumped 74 percent from 2004 to 2009, according to the Nielsen Company. The company estimates that category to increase 15 percent to 25 percent annually. By 2012, the gluten-free category is projected to top $2.6 billion in sales.

That spells good news for the 3 million Americans suffering from celiac disease. May is Celiac Disease Awareness Month, a genetic disorder that can cause weight loss, malnutrition and other stomach problems if not treated by avoiding gluten.

"The prevalence of celiac is on the rise, and there are many theories as to why," said Carol Shilson, executive director of the University of Chicago Celiac Disease Center. "An important one is the hygiene theory. We??re getting so clean that our immune systems aren??t as strong as they were and we are more open to autoimmune diseases like celiac disease. In less developed areas of the world, celiac is much less prevalent."

Many consumers who don??t have celiac disease perceive gluten-free products as healthier and are eating those foods, too. Because of this increasing interest in products without gluten, these foods have hit the mainstream shelves with products like a gluten-free Chex cereal, Duncan Hines cake mixes and Jones Dairy sausage products.

King Arthur Flour and Bob??s Red Mill offer gluten-free varieties. Anheuser-Busch introduced a gluten-free beer called Redbridge, while Trader Joe??s has a gluten-free whole grain beverage.