Open a magazine or turn on the television today and you’ll probably hear the term “gluten- free”. This newly mass-publicized diet is popular with high-profile celebrities like Elisabeth Hasselbeck and Jenny McCarthy. Even people who don’t have a diagnosed medical issue are trying to eat gluten-free.

The Center for Celiac Research and Treatment reports that a whopping one in every 133 Americans has Celiac Disease, the formal term for the destructive autoimmune response triggered by gluten. The Center estimates that an additional 18 million people have a less severe type of Celiac Disease, termed gluten sensitivity.

Whatever the reason behind your change in diet, eating gluten-free isn’t easy. Although an FDA labeling rule is in the works, there is currently no regulation that requires manufacturers to label gluten-containing foods. So, unfortunately, even if you carefully examine each ingredient, you may be lulled into eating gluten.

Celiacs and other gluten-free faithful know to vigilant, but here are three surprising foods that often make it past even the most sensitive radar.

1. Oatmeal

Sure, pure oats don’t contain any of the gluten found in wheat, rye, or barley. But, beware; the oats you find in the supermarket are rarely pure. When oats are grown and processed, they are often cross-contaminated by gluten-containing grains. There is good news—many companies now produce and process oats specifically without the interference of other grains.

2. Soy Sauce

It may not seem logical, but many soy sauces list wheat as one of the first ingredients. If you’re craving an Asian flavor, try tamari. It’s usually gluten-free and tastes very similar to soy sauce. Some soy sauce manufacturers also have gluten-free products. Just make sure to triple-check the label.

3. Pickles

Pickles are just cucumbers and vinegar, right? Not always. There is an unassuming ingredient called malt vinegar present in some pickles. It’s made from barley–a gluten-containing grain. Steer clear of any pickles like this. Brands like Claussen, Vlasic, and others are made with distilled vinegar and considered gluten-free.

What glutinous foods have surprised you?