Letter to the editor regarding the article 'EFSA's toxicological assessment of aspartame: was it even-handedly trying to identify possible unreliable positives and unreliable negatives?'

This letter is in response to a recent paper by Millstone and Dawson (2019) in which the authors criticise the re-evaluation of the high intensity sweetener aspartame in 2013 by the former EFSA's Panel on Food Additives and Nutrient Sources added to Food, on the grounds that EFSA did not follow its own procedures for its risk assessment. Moreover, the authors claim that the appraisal of the available studies was asymmetrically more alert to putative false positives than to possible false negatives. In this letter it is shown that the methodology for collection and selection of the scientific information used as a basis for the aspartame risk assessment, and the inclusion/exclusion criteria applied were defined a priori and documented in the published opinion. Furthermore, the Panel applied a Weight-of-Evidence approach combined with an analysis of the biological relevance of the appraised and validated evidence for its analysis, integration and interpretation, followed by an uncertainty analysis. Finally, an analysis of the distribution of negative versus positive outcome of the studies in the context of reliability showed that the claim of bias in the scientific risk assessment of aspartame is not substantiated.