Do you sometimes spend extra time at the market and still walk out unsure about what you’ve bought? If you avoid certain foods because of dietary choices or restrictions, you know that label reading can be downright maddening: “I wonder what that is. Does it contain gluten? Was it derived from animal sources?” Food shopping shouldn’t have to be so stressful.

Take a deep breath: Here, we decipher 15 common but confusing ingredients, highlighting what’s safe and what’s not for those who eat gluten free, eschew dairy, or seek to avoid all animal-based products.

Caramel coloring. Although it’s possible to make caramel color from gluten-containing ingredients like barley malt, in North America it’s typically made from corn, rendering it safe for gluten-free diets.

Carmine. You might see this red coloring listed on labels as carmine, cochineal, or cochineal extract. The FDA classifies it as a natural color additive, but unfortunately for vegans, it’s derived from the cochineal beetle, a type of insect. If you strictly avoid animal-based products, don’t purchase items that contain it.

Casein and whey. Casein and whey are two proteins found in milk, so vegans and people with a milk allergy need to avoid them. All FDA-regulated foods containing casein and whey are required to list the word “milk” on the label, so be sure to read the ingredients statement, even if the product says “dairy-free” or “nondairy.”

Gelatin. Who would have thought colorful Jell-O and similar products contain animal products? But they do: Gelatin is derived from various animal byproducts. Kosher gelatin, on the other hand, is made from a sea vegetable, so it’s suitable for vegans and vegetarians.

Maltodextrin. The “malt” in barley malt, malt syrup, and malt extract indicates the presence of gluten. Maltodextrin, however, is actually gluten free. It can be derived from a variety of starches, but products made in the United States are unlikely to use wheat; and even if it is derived from wheat, maltodextrin is such a highly processed ingredient that the protein is removed, making it gluten free. Still, when it’s made from wheat starch, “wheat” must be declared on the label.

Maltose. Also called malt sugar, this is a disaccharide (two sugar units); it is gluten free, dairy free, and vegan.

Modified food starch. This can be made from a variety of food starches, including corn. It is gluten free unless made from wheat. When it is made from wheat, “wheat” will appear on the label.

Monosodium glutamate (MSG). This flavor enhancer is made from fermenting corn, sugar beets, or sugar cane; it’s linked to migraines and hyperactivity in children. MSG is gluten free; glutamate refers to the amino acid glutamic acid, not gluten.

Nondairy. It’s hard to believe, but foods labeled “nondairy” can in fact contain milk proteins, thanks to confusing FDA regulations that do not define nondairy as milk-free. In fact, “nondairy” products are allowed to contain up to 0.5 percent milk by weight, typically as casein (milk protein). Be sure to read the ingredients label; if the product contains milk it will be clearly stated within the list or in a “contains” statement at the bottom.

Plant stanols and sterols. These compounds naturally exist in fruits, vegetables, vegetable oils, whole grains, nuts, and seeds; research shows that they reduce total and LDL cholesterol, while leaving HDL levels unaffected. They’re now infused into fortified foods such as soy products, salad dressings, butter-substitute spreads, and even chips. Both are gluten free and vegan.

Rennet. Rennet or rennin is an enzyme used in cheese making. It is derived from milk-fed calves, so both vegans and vegetarians tend to avoid it. Vegetable-based rennet is available and is usually labeled as such on ingredients statements.

Vinegar. All distilled vinegars, except malt vinegar, are gluten free and vegan.

Yeast. Active dry, autolyzed, baker’s, and nutritional yeasts are gluten free. Brewer’s yeast, when a byproduct of beer, is not gluten free. It’s difficult to know the source of brewer’s yeast from a label, so if you’re gluten averse, avoid all brewer’s yeast if you can’t trace the source. Yeast extract may or may not be made from barley. Because barley doesn’t have to be called out on U.S. food labels, gluten-free eaters should use caution when they see this ingredient.