Is There a Gluten-Free Option for Thickening Sauces and Soups?

"Chances are, most of us will need to cook a gluten-free meal
at some point: About 1 in 150 Americans are gluten-intolerant,
which means they can't digest the protein in wheat and some other
grains. Rice, soy, corn, potato, tapioca, quinoa, and buckwheat
all get the gluten-free green light. Use cornstarch as a thickener
rather than flour, but keep in mind that it has twice the power of
flour so you'll need less."

-Ellie Krieger, Food Network Magazine April 2010