A number of studies have found that the widely used food additive carrageenan causes cancer in laboratory animals, and, its use in human food should be reconsidered.

Although the studies have been conducted only in animals, enough evidence exists about the cancer-causing effects of carrageenan to limit the use of the food additive.

Carrageenan, an extract from red seaweed, is used in a variety of foods such as milk products and processed meat as a thickener, stabilizer and texturizer. It can be found in products such as ice cream, whipped cream, pudding and yogurt.

The researchers reviewed 45 previously published animal studies and found that carrageenan is associated with the formation of ulcers in the intestines and cancerous tumors in the gut.

Both undegraded as well as degraded forms of carrageenan are associated with malignancies.

Carrageenan is taken up by intestinal cells rather easily, but the cells are unable to metabolize it. As carrageenan accumulates in cells it may cause them to breakdown, and over time this process could lead to ulceration, she noted.

Ulceration seems to be associated with the development of malignancies.

In 1972, the Food and Drug Administration (FDA) proposed limiting the type of carrageenan that could be used in food. But the regulatory effort was rescinded in 1979.

There has been no substantive review by the FDA of carrageenan since the studies undertaken more than two decades ago. However, there has been increased evidence regarding the cancer-promotion activity of undegraded carrageenan and further confirmation of the potential of degraded carrageenan.

Environmental Health Perspectives October 2001;109:983-994