To answer this question it might help to consider what exactly polenta is. Polenta is the name given to cooked yellow cornmeal; so essentially polenta is the name of the cooked product rather than the ingredient. However cornmeal and polenta are often used interchangeably.
Cornmeal is made from corn kernels (generally yellow corn) that have been ground into a coarse grit. And because corn is naturally free from gluten, polenta is considered a gluten free product. Confusion can arise around the type of protein in corn. Gluten is essentially a protein found in grains like wheat, rye and barley. Corn does not contain this protein but it does contain another protein called zein, which can sometimes cause symptoms similar to those experienced by people with gluten sensitivity or celiac disease.
Cornmeal is considered a wholegrain and since many gluten free foods are made from refined carbohydrates, such as potato and rice, polenta is an excellent way to include whole grains in a gluten-free diet. It’s also a source of fibre and protein.
When buying polenta it’s wise to seek out products that are certified gluten free to ensure the product has not been cross-contaminated.