Next time you're scooping up some ice cream or yogurt, check the label. You may see something called carrageenan listed among the ingredients.

Carrageenan is a natural food additive that is mired in some controversy. It's used primarily to thicken and stabilize foods and is found in a range of products from chocolate milk to sour cream.

Some studies have found that carrageenan and similar-type emulsifiers trigger inflammatory disease. In some animal studies, the additive has been linked to destructive gastrointestinal issues including inflammatory bowel disease and possibly even tumor production.

"Carrageenan predictably causes inflammation, which can lead to ulcerations and bleeding," noted carrageenan researcher Joanne Tobacman, M.D., associate professor of clinical medicine at the University of Illinois School of Medicine at Chicago, told Prevention.

Tobacman's previous work showed a connection between carrageenan and gastrointestinal cancer in lab animals. She's currently spearheading research funded through the National Institutes of Health that is investigating carrageenan's effect on ulcerative colitis and other diseases like diabetes.

Yet other reports and studies have shown there is no viable connection between carrageenan and health risks. Still, a committee that proposes rules for the organic food industry recently voted to ban it from organic products, NPR reports, based on those previously mentioned studies that link carrageenan to health problems.

What does carrageenan do?

Carrageenan is derived from red seaweed. It's added to some foods and drinks, especially dairy products, for several main reasons.

  • To thicken: Manufacturers may include carrageenan in low-fat or no-fat foods like cottage cheese or sour cream as a substitute for fat. It thickens them, making them creamier and helps them taste fuller.
  • To stabilize drinks: Some beverages like chocolate milk or some shakes will separate if they aren't stirred or shaken. Adding carrageenan keeps the drinks stabilized so you don't have to shake them before you drink them.
  • To help foods gel: The addition of carrageenan can help custards, puddings and pie filling firm up and take shape.

Where you might find carrageenan

Carrageenan is most common in dairy products, but it may also pop up in soups, frozen dinners and chocolate bars. It's also used in some toothpastes, lotions, shampoos and even pet food.

If you are concerned about carrageenan in your diet, there are a few steps you can take.

Check the label. Carrageenan must be listed in the ingredients if it's in a product.

Look it up. The Cornucopia Institute, an organic watchdog group, keeps a shopping guide to help people looking to avoid carrageenan.

Editor's note: This story has been updated since it was originally published in March 2015.

Mary Jo DiLonardo covers a wide range of topics focused on nature, health, science and anything that helps make the world a better place.

What is carrageenan?
Carrageenan is in everything from dairy products to toothpaste. Here's what you need to know about the natural but controversial additive.