What does it do? Primarily used as an emulsifier, stabilizer and thickener, this gum is popular as a fat replacement in low-fat foods because it provides a "fat feel" to the food.

Is it safe? It is being studied because it has been shown to cause cancer and ulcerative colitis in lab animals, but the Food and Drug Administration regards it as 100 percent safe in the allowable amounts. According to Barry Swanson, professor of food science at Washington State University, it's not broken down in the stomach and is a pretty safe additive. The Center for Science in the Public Interest agrees, rating it "safe."

Xanthan gum and guar gum

What are they?

• Xanthan gum is a naturally occurring carbohydrate made by fermenting corn sugar with a microbe called Xanthomonas campestris.
• Guar gum is made from the seeds of the guar plant, cultivated in India.

Where do you find them? Edy's Whole Fruit Bars; Ben & Jerry's Fudge Central Ice Cream; Wish-Bone Deluxe French Dressing.

What do they do? They act as thickening and emulsifying agents; they prevent sugar crystals from forming in candy; they form the gel-like consistency in pudding; and they keep oil and water mixed together in salad dressings. In fact, guar gum has five to eight times the thickening power of cornstarch and is used not only to thicken our food and livestock feed, but also in paper manufacturing, textiles, printing, cosmetics and pharmaceuticals, explains Ruth Winter, author of A Consumer's Dictionary of Food Additives (Three Rivers, 2004).

Are they safe? Yes, relatively, because they are not digestible and are, therefore, not absorbed by the body. But the FDA banned guar gum from use in drugs and weight-loss products in 1997 because it swells when wet, adds Winter. According to the Center for Science in the Public Interest, gums "are poorly tested, though probably safe."

Potassium sorbate

What is it? Potassium sorbate is a salt version of sorbic acid, a polyunsaturated fat.

Where do you find it? Smucker's Low Sugar Red Raspberry Preserves; Land o' Lakes Light Whipped Butter; SnackWell's Devil's Food Cookies.

What does it do? It is used as a preservative, particularly to inhibit mold growth.

It is safe when eaten in allowable doses, according to Swanson. The Center for Science in the Public Interest has also rated it as safe.

Phosphoric acid

What is it? Phosphoric acid is a naturally occurring organic acid found in all plants and animals.

Where do you find it? Coke, Pepsi and other carbonated drinks.

What does it do? It is primarily used as flavoring to impart a tart, acidic taste to soda. In potato products and cheeses, it adds desirable flavor and stabilizes color.

Is it safe? In pure form, it is a strong acid, but it's diluted for use in food. "Bleach is a strong solution also, but when it's put in small concentrations in our drinking water, it's safe and effective," says Swanson. The Center for Science in the Public Interest gives it a safe rating.

BHT/BHA

What are they? Butylated hydroxytoluene and butylated hydroxyanisole are metabolizing enzymes that act as antioxidants.

Where do you find them? Kellogg's Rice Krispies; Quaker Chewy Granola Bars; Celeste Pizza for One Pepperoni Pizza.

What do they do? They keep the fats and oils in foods from turning rancid.

Are they safe? Some animal experiments have shown that these compounds reduce the risk of cancer, while other studies point to an increased risk. The FDA considers BHT and BHA "Generally Regarded As Safe" (the safest rating a food substance can get), but other groups, such as the Center for Science in the Public Interest, recommend avoiding them.