You may notice that some familiar substances, when added to foods, seem foreign when listed on the ingredient label—for example, ascorbic acid (vitamin C), alpha tocopherol (vitamin E), beta-carotene (source of vitamin A) and thiamin mononitrate (vitamin B1). Other additives—such as calcium propionate, erythorbic acid, sodium benzoate and sodium carbo-xymethylcellulose—may sound sinister, but are actually safe preservatives, color stabilizers and thickening and stabilizing agents.

Many additives are now followed by descriptive statements, for example, "sodium benzoate (preservative)." If you're concerned about a particular additive for health reasons, find out all the chemical names by which it may appear in the ingredients list. Sulfite-sensitive people won't have trouble recognizing sodium sulfite or potassium bisulfite, but what about sulfur dioxide? This irritant for asthmatics is created when sulfites come into contact with heat or acid, such as gastric acid in the stomach.

If you suffer from "Chinese restaurant syndrome," be leery of products listing the flavor enhancer "hydrolyzed vegetable protein" (HVP) or "natural flavorings"—HVP contains MSG, and flavorings may include MSG or HVP.

Vegetarians and vegans may need to do some detective work when reading food labels. Many common additives, such as monoglycerides and diglycerides (emulsifiers), glycerol (extends shelf life), natural flavors and maltodextrins (thickening agents), may be nonvegetarian. These additives, or substances used to process the additives, may be derived from meat, fish or fowl. Your best bet is to call the manufacturer and ask if animal-derived ingredients are used.

To obtain a copy of Food Additives: A Shopper's Guide to What's Safe & What's Not (KISS For Health Publishing), call 760.735.8101. This handy, pocket-size book classifies more than 600 commonly used food additives.