The Food and Drug Administration issued Friday the first legally binding rules for what food companies can legally label "gluten-free."
The rules should help millions of Americans who can't tolerate gluten in their diet.
Gluten is a protein in wheat, barley and rye. Bakers appreciate its gluey texture for making bread. But when people with celiac disease eat it, it causes their immune systems to attack their small intestines.
About 3 million people in the U.S. have celiac disease. But they're not the only ones seeking gluten-free food, which has rapidly grown into $4.2 billion market.
A small number of children and adults have wheat allergy. And 18 million Americans who have neither celiac or wheat allergy experience symptoms from eating wheat — called gluten sensitivity. And still others may buy gluten-free food because they're paleo, or following another diet.
Many products, from beer to flour, already carry the gluten-free label. But until now there's been no official standard for exactly how free of gluten such foods have to be, though the FDA has been pondering how to set one since 2004.
The FDA's new rule says gluten free foods can't contain more than 20 parts per million of gluten. Below that level, gluten can't be detected reliably and only very rare individuals would react to it.
According to the FDA, most gluten-free food on the market already meets this standard. It goes into effect one year from now.
Andrea Levario, executive director of the American Celiac Disease Alliance, called the label a "tool that has been desperately needed," in a statement.
Doctors who treat people with celiac and gluten sensitivity were also enthusiastic.
"This is a really valuable step forward," says William Chey, a gastroenterologist at the University of Michigan.