Carrageenan may cause stomach lesions, cancer

From: Robina Suwol
Date: 20 Oct 2001
Time: 19:57:21
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Carrageenan may cause stomach lesions, cancer

Wednesday, October 17, 2001 By Environmental News Network

Containers of pudding, ice cream, yogurt, or cottage cheese may include the ingredient carrageenan, a thickener derived from red seaweed. For decades, it has been presumed to be safe to eat, but new research from a medical doctor on the faculty of the University of Iowa shows that presumption may be wrong.

Carrageenan is a water-soluble polymer, also known as a gum, that is used as a fat substitute in processed meats and can be found in condensed milk and some soy milk products.

"Evidence from animal models has demonstrated that degraded carrageenan causes ulcerations and malignancies in the gastrointestinal tract," said Joanne Tobacman, M.D., University of Iowa assistant professor of clinical internal medicine.

After conducting epidemiologic and laboratory research on carrageenan, Dr. Tobacman published an extensive review of 45 investigations on harmful gastrointestinal effects of carrageenan in animal experiments. The article was published in the October issue of Environmental Health Perspectives, the journal of the National Institute for Environmental Health Sciences.

Findings over the years in Europe and the United States suggest that assumptions about the safety of carrageenan need to be reconsidered and that carrageenan may need to be better regulated by the Food and Drug Administration (FDA), said Dr. Tobacman. "There seems to be enough evidence associating carrageenan with significant gastrointestinal lesions, including malignancies, to avoid ingesting it," she said.

"I think the first consideration is to inform people about the risks that have been associated with carrageenan," she added. "There was evidence back in the 1970s that carrageenan has harmful effects, and I think we've waited too long to act on that information."

In 1972 the FDA determined there was sufficient evidence from animal experiments to propose limiting the type of carrageenan that could be used in food products. "Many authoritative sources thought that the proposal actually became a regulation. However, it didn't," Tobacman said.

In 1982, the International Agency for Research on Cancer found enough evidence in animal models linking degraded carrageenan with gastrointestinal cancers to state that it posed a carcinogenic risk to humans. Other research groups also have listed it as a known carcinogen based on animal studies.

Degraded carrageenan has a molecular weight of 30,000 or lower, whereas undegraded carrageenan has a molecular weight of 100,000 or higher. There is evidence that degraded carrageenan causes intestinal ulcerations and cancers.

In addition, Tobacman explained, undegraded carrageenan, which has the higher molecular weight and is thought not to be absorbed in the intestine, may also be associated with the promotion of malignancy and inflammation in the gastrointestinal tract.

Tobacman said other gums with similar thickening properties can be used instead of carrageenan. These gums include locust bean, guar, and xanthan.

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