IARC Monographs evaluation of the carcinogenicity of aspartame, methyleugenol, and isoeugenol

The International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization (WHO), has evaluated the carcinogenicity of aspartame, methyleugenol, and isoeugenol.

A Working Group of 25 international experts from 12 countries was convened by the IARC Monographs programme for a meeting on 6–13 June 2023 in Lyon, France. Four Observers also attended the meeting.

After thoroughly reviewing the available scientific literature, the Working Group classified methyleugenol as probably carcinogenic to humans (Group 2A), on the basis of sufficient evidence for cancer in experimental animals, strong mechanistic evidence in experimental systems, and inadequate evidence regarding cancer in humans. Methyleugenol was previously evaluated as Group 2B in IARC Monographs Volume 101, published in 2013.

The Working Group classified both aspartame and isoeugenol as possibly carcinogenic to humans (Group 2B). Neither aspartame nor isoeugenol had previously been evaluated by the IARC Monographs programme.

Aspartame was classified as Group 2B on the basis of limited evidence for cancer in humans, limited evidence for cancer in experimental animals, and limited mechanistic evidence.

Isoeugenol was classified as Group 2B on the basis of sufficient evidence for cancer in experimental animals, inadequate mechanistic evidence, and inadequate evidence regarding cancer in humans.

A summary of the final evaluations has now been published online in The Lancet Oncology. The detailed assessment will be published as Volume 134 of the IARC Monographs.

Riboli E, Beland FA, Lachenmeier DW, Marques MMSD, Phillips D, Schernhammer E, et al.
Carcinogenicity of aspartame, isoeugenol, and methyleugenol
Lancet Oncol, Published online 13 July 2023;
https://doi.org/10.1016/S1470-2045(23)00341-8

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