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

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 56 (1993) (p. 83)

Chemicals found in pickled vegetables

CAS No.: 16071-96-8
Chem. Abstr. Name: Bis[m-(methanethiolato)]tetranitrosodiiron

CAS No.: 90-19-7
Chem. Abstr. Name: 2-(3,4-Dihydroxyphenyl)-3,5-dihydroxy-7-methoxy-4H-1-benzopyran-4-one

CAS No.: 480-19-3
Chem. Abstr. Name: 3,5,7-Trihydroxy-2-(4-hydroxy-3-methoxyphenyl)-4H-1-benzopyran-4-one

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Traditional processes for pickling vegetables in some regions of China, Japan and Korea involve fermentation of local vegetables, with or without salting. Such preparations are often eaten daily or several times a week. Among the many compounds found at low levels in pickled vegetables are N-nitrosamines and Roussin red methyl ester, which reacts with secondary amines to form N-nitrosamines.

5.2 Human carcinogenicity data

A cohort study from Japan suggests that intake of pickled vegetables is positively associated with risk for stomach cancer, but further cohort studies from Japan and Hawaii do not support an association. The methods used to determine dietary intake differed in these studies, and the types of pickled vegetables included may also have differed.

Seven case-control studies of stomach cancer have been conducted that included data on consumption of pickled vegetables. Three conducted in Japan gave negative results and another gave positive results. One study of Japanese in Hawaii showed an association, but two conducted in China did not.

A large case-control study of oesophageal cancer in Hong Kong showed a significant dose-response relationship between consumption of pickled vegetables and oesophageal cancer, after potential confounding factors were taken into account. A study in a high- and an intermediate-risk area in China showed an association with consumption of pickled vegetable juice, although there was no association with consumption of pickled vegetables; a population-based study in a high-risk area of northern China also gave negative results for pickled vegetables.

Intake of salted/pickled vegetables (leafy vegetables, roots and olives) has been investigated in two case-control studies of nasopharyngeal carcinoma from China and in one from Tunisia. One of these studies, from Guangxi, China, showed a significant association with eating salted/pickled vegetables.

Two correlation studies carried out in Japan and one carried out in Hawaii suggest a relationship between consumption of pickled vegetables and stomach cancer, but the results are not completely consistent. The results of correlation studies on oesophageal cancer were also inconsistent.

No data were available on pickled vegetables made elsewhere in the world.

5.3 Animal carcinogenicity data

No adequate study on the carcinogenicity of pickled vegetables to experimental animals was available to the Working Group.

5.4 Other relevant data

In a single study, extracts of pickled vegetables from northern China induced morphological transformation of Syrian hamster embryo cells in culture. Extracts of pickled vegetables from northern China and Japan are mutagenic to bacteria.

5.5 Evaluation

There is limited evidence in humans for the carcinogenicity of pickled vegetables as prepared traditionally in Asia.

There is inadequate evidence in experimental animals for the carcinogenicity of pickled vegetables.

Overall evaluation

Pickled vegetables (traditional Asian) are possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.

Synonyms for Bis[m-(methanethiolato)]tetranitrosodiiron

Synonyms for 2-(3,4-Dihydroxyphenyl)-3,5-dihydroxy-7-methoxy-4H-1-benzopyran-4-one

Synonyms for 3,5,7-Trihydroxy-2-(4-hydroxy-3-methoxyphenyl)-4H-1-benzopyran-4-one

Last updated 08/21/1997

    See Also:
       Toxicological Abbreviations