In a statement published today, the European Food Safety Authority (EFSA) concludes that two recent publications on the safety of artificial sweeteners, namely a carcinogenicity study in mice (Soffritti et al., 2010) and an epidemiological study on the association between intakes of artificially sweetened soft drinks and increased incidence of preterm delivery (Halldorsson et al., 2010) do not give reason to reconsider previous safety assessments of aspartame or of other sweeteners currently authorised in the European Union. EFSA’s review of these studies has been carried out in co-operation with the French agency for food, environment and occupational health safety, Anses.
At its plenary meeting on 1-2 March 2011, EFSA’s Panel on Food Additives and Nutrient Sources added to Food (ANS) will consider the Authority’s statement and the possible need for further work in relation to these studies. EFSA will continue monitoring the scientific literature in order to identify new scientific evidence for sweeteners that may indicate a possible risk for human health or which may otherwise affect the safety assessment of these food additives.
In response to a request for technical assistance from the European Commission, EFSA reviewed the Soffritti et al. (2010) publication on a long-term carcinogenicity study in mice exposed to the artificial sweetener aspartame through feed. EFSA scientists concluded that, on the basis of the information available in the publication, the validity of the study and its statistical approach cannot be assessed and its results cannot be interpreted. Regarding the design of the study, EFSA advised that experimental studies carried out over animals’ lifetimes can lead to erroneous conclusions. Older animals for instance are more susceptible to illness and when a carcinogenicity study in mice is extended beyond the recommended 104 weeks, age-related pathological changes (such as spontaneous tumours) can appear which may confound the interpretation of any compound-related effects.
EFSA noted that Swiss mice (used in this study) are known to have a high incidence of spontaneous hepatic and pulmonary tumours and that the increased incidence of these tumours reported in the study fall within the historical control range recorded in this laboratory for these tumours in these mice. Furthermore, these hepatic tumours in mice are not regarded by toxicologists as being relevant for human risk assessment when they are induced by non-genotoxic substances such as aspartame. Overall, EFSA concluded that the findings presented in Soffritti et al. (2010) do not provide sufficient scientific evidence to reconsider the previous evaluations by EFSA on aspartame that concluded on the lack of genotoxicity and carcinogenicity of aspartame.
EFSA also assessed the Halldorsson et al. (2010) publication that reports findings suggesting that the daily intake of artificially sweetened soft drinks may be associated with an increased risk of preterm delivery. EFSA concluded that there is no evidence available in this study to support a causal relationship between the consumption of artificially sweetened soft drinks and preterm delivery and that additional studies would be required either to confirm or reject such an association, as indicated by the authors. Given that the association found by the authors appears to be primarily related to medically induced (rather than spontaneous) preterm deliveries, EFSA stressed that medical history and criteria on which medical decisions to induce delivery were based are factors which should be investigated further. EFSA recommended that future studies should also investigate other important confounding factors such as exposure to other substances in the diet which might have an effect on pregnancy.
EFSA keeps the safety of sweeteners and aspartame under regular review. In March 2009 , the ANS Panel concluded that on the basis of all the evidence currently available, including the ERF study published in 2007, there is no indication of any genotoxic or carcinogenic potential of aspartame and no reason to revise the previously established Acceptable Daily Intake for aspartame of 40 mg/kg body weight. An earlier opinion , following the first study on aspartame by the European Ramazzini Foundation, was adopted by the former AFC Panel in 2006.
EFSA has requested the complete data set of the Soffritti et al., 2010 study and will meet with the authors to discuss the study design and findings.