International Agency for Research on Cancer (IARC) - Summaries & Evaluations


VOL.: 31 (1983) (p. 79)

CAS No.: 9000-07-1

5. Summary of Data Reported and Evaluation

5.1 Experimental data

Native (undegraded) carrageenan was tested for carcinogenicity in rats and hamsters by administration in the diet; no evidence of carcinogenicity was found. In female rats treated with azoxymethane or N-nitrosomethylurea together with native carrageenan in the diet, a greater incidence of colorectal cancers was observed than with treatment by azoxymethane or N-nitrosomethylurea alone. Degraded carrageenan was tested in rats by administration in the diet, in the drinking-water and by oral intubation, in four experiments; colorectal cancers were induced in each study.

Native carrageenan has not been tested in short-term assays. Degraded carrageenan was not mutagenic in bacteria or in mammalian cells in vitro. The data were inadequate to evaluate the activity of degraded carrageenan in short-term tests.

Native or degraded carrageenan had no reproductive or teratogenic effect in rats or hamsters.

5.2 Human data

Carrageenan-containing seeweeds have been used since at least two hundred years, and isolated carrageenan has been used as a food additive since 1937. Carrageenan is used in the manufacture of food, drug and cosmetic products and in multiple industrial applications, resulting in wide human exposure.

No data were available to assess the teratogenicity or chromosomal effects of this compound in humans.

No case report or epidemiological study on the carcinogenicity of native or degraded carrageenan was available to the Working Group.

5.3 Evaluation

The available data do not provide evidence that native (undegraded) carrageenan is carcinogenic to experimental animals. In the absence of epidemiological data, no evaluation of the carcinogenicity of native carrageenan to humans could be made.

Experiments in rats with doses of degraded carrageenan comparable to those used to test native carrageenan provide sufficient evidence for the carcinogenicity of degraded carrageenan in rats. No data on humans were available.

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluation: Vol. 10 (1976)

Subsequent evaluation: Suppl. 7 (1987) (p. 59: Carrageenan, native - Group 3; Carrageenan, degraded - Group 2B)


Last updated: 16 April 1998

    See Also:
       Toxicological Abbreviations
       Carrageenan (WHO Food Additives Series 42)
       CARRAGEENAN (JECFA Evaluation)