The U.S. Food and Drug Administration on Friday issued a set of standards for food manufacturers wishing to label a product “gluten-free.” The agency set a limit of 20 parts per million for the amount of gluten that may be present in foods marketed as gluten-free. The rule also extends to foods labeled “free of gluten,” “without gluten” or “no gluten.” FDA’s final rule on gluten-free labeling comes six years after the agency published its proposed definition of gluten-free in 2007 and 9 years after Congress requested a universal definition of gluten-free from the agency in the Food Allergen Labeling and Consumer Protection Act (FALCPA). The push for a standard definition for the term “gluten-free” has been spurred by an increase in the number of people diagnosed with celiac disease over the past few years. Celiac disease prevents a person from being able to absorb nutrients after eating gluten. An estimated 1 percent of Americans are thought to have the condition, although 83 percent of cases currently go undiagnosed. “Adherence to a gluten-free diet is the key to treating celiac disease, which can be very disruptive to everyday life,” said Margaret Hamburg, commissioner of FDA, in a comment on the new rule. “The FDA’s new ‘gluten-free’ definition will help people with this condition make food choices with confidence and allow them to better manage their health.” Sales of gluten-free foods have been on the rise recently, reaching $2.6 billion in 2010. That figure is estimated to hit $5 billion by 2015. FDA said it chose 20 ppm rather than 0 ppm as the limit because current scientific methods can’t detect levels of gluten below 20 ppm. “In addition, some celiac disease researchers and some epidemiological evidence suggest that most individuals with celiac disease can tolerate variable trace amounts and concentrations of gluten in foods (including levels that are less than 20 ppm gluten) without causing adverse health effects,” the agency stated in its Q & A on the new rule. The amount of 20 ppm of gluten in food can be visualized by picturing 2 grains of salt in a piece of bread. Celiac awareness advocates praised the release of the rule. “For years, gluten-free labels have gone unregulated, putting our gluten-free community in danger,” Alice Bast, president of the National Foundation for Celiac Awareness, said in a statement Friday. “We applaud the FDA for finally publishing a standard definition of gluten-free.” The new rule applies to all FDA-regulated foods and drinks, including dietary supplements.