Another interesting and commonplace food additive is carrageenan, an emulsifying agent extracted from red seaweed. While this polysaccharide has been used forever as a thickener and bonding agent in everything from ice cream to toothpaste (taking the place of animal-derived gelatin), in the past several years there has been a growing concern about carrageenan as a potential carcinogen and trigger to bowel disorders. While there is some remote possibility that this is true, mostly this stems from confusion over an industrial agent that at one point was also called carrageenan, though it substantially differed from the naturally occurring molecule.
For the most part, carrageenan is probably safe. In fact, the red seaweed that provides carrageenan has been consumed as a natural remedy for respiratory disorders and as a laxative. However, for those who already have digestive disorders such as colitis, it might be worth avoiding this food additive as much as possible.