According to UK academics at the University of Sussex, the safety of aspartame for human consumption has not been ‘adequately proven’.

Since 1974, research has linked aspartame consumption with heightened risk of brain damage, liver and lung cancer, brain lesions and neuroendocrine disorders, the Sussex researchers stressed.

Nevertheless, in 2013 the European Food Safety Authority (EFSA) concluded that aspartame and its breakdown products are ‘safe for [the] general population’, including infants, children and pregnant women. At the time, EFSA ruled out potential association between aspartame consumption and brain damage or cancer.

Currently, in Europe aspartame is authorised to be used as a food additive in foodstuffs such as drinks, desserts, sweets, dairy, chewing gums, energy-reducing and weight control products and as a table-top sweetener.

In a recently published study, Professor Erik Millstone and Dr Elisabeth Dawson detail what they describe as ‘serious flaws’ in EFSA’s 2013 safety assessment of the artificial sweetener.

‘A low bar was set for critical studies’

According to their investigation, the EFSA panel discounted the results of ‘every single one’ of 73 studies suggesting aspartame could be harmful to health. In contrast, 84% of the studies providing no prima facie evidence of harm were accepted as unproblematic and reliable.

“Our analysis of the evidence shows that, if the benchmarks the panel used to evaluate the results of reassuring studies had been consistently used to evaluate the results of studies that provided evidence that aspartame maybe unsafe then they would have been obliged to conclude there was sufficient evidence to indicate aspartame is not acceptably safe,”​ Professor Millstone said.

The authorisation of aspartame adopted a ‘low-hurdle’ for the acceptability of negative studies - including studies previously dubbed ‘woefully inadequate’ and ‘worthless’ by experts – while also applying ‘unreachably high hurdles’ for studies indicating adverse effects, they argued.

Professor Millstone and Dr Dawson added that ‘many’ of those 73 studies questioning aspartame’s safety were ‘far more reliable’ than ‘most’ of the studies that provided no indication of risk.

Moreover, EFSA’s conclusions demonstrated ‘puzzling anomalies’ including inconsistent and unacknowledged assumptions, and breached the advisory body’s own guidelines on risk assessment transparency on ‘multiple grounds’, the UK academics claimed.

“This research adds weight to the argument that authorisation to sell or use aspartame should be suspended throughout the EU, including in the UK, pending a thorough re-examination of all the evidence by a reconvened EFSA that is able to satisfy critics and the public that they operate in a fully transparent and accountable manner applying a fair and consistent approach to evaluation and decision making.”

Conflicts of interest at play?

Professor Millstone expressed concern that EFSA’s assessment, completed by the Panel on Food Additives and Flavourings, could have been influenced by commercial or institutional conflicts of interest.

“In my opinion, based on this research, the question of whether commercial conflicts of interest may have affected the panel’s report can never be adequately ruled out because all meetings all took place behind closed doors.”​

He told FoodNavigator that EFSA should be doing more to ensure its decisions are not swayed by outside influences. “I believe that the EFSA Board, in collaboration with DG-Sante at the European Commission, should ensure that no members of the EFSA Board, or its scientific committee or any of its scientific panels have any commercial conflicts of interest. EFSA must abandon its rhetorical narrative that ‘an interest is not necessarily a conflict of interest’.​

“By institutional conflicts of interest, I mean that they should not work for, or advise, any organisation that had previously declared aspartame to be safe.”​

Aspartame safety ‘needs to be reviewed’

Professor Millstone is calling for the authorisation to sell or use aspartame in the EU to be suspended pending an independent re-examination of relevant evidence. “The safety and acceptability of aspartame needs to be reviewed by a panel of experts none of whom have any commercial or institutional conflicts of interest.”​

This review should include ‘key documents’ that Professor Millstone claims were omitted from the 2013 file. According to the expert on food chemical safety policy, EFSA failed to pass a 30 document dossier he submitted​ detailing the inadequacy of 15 ‘pivotal studies’ pass on to its scientific advisors.

‘Robust grounds’ for mistrust of EFSA

Earlier this year, the European Commission adopted new rules designed to increase transparency in the EU food safety risk assessment process​. According to the EC, European citizens report a lack of trust in EFSA, particularly the authorisation process.

EFSA’s food safety assessments are currently primarily based on industry studies – data and information generated and funded by the applicant – and this has led to a degree of suspicion. According to the EC’s assessment, such misgivings are compounded by the strict confidentiality rules EFSA operates under regarding these studies, which are currently not publicly disclosed.

Professor Millstone told this publication that his recent paper provides ‘robust grounds’ for consumers to mistrust EFSA and its judgements.

“EFSA was supposed to provide ‘evidence-based policy-making’, but instead it seems to be reproducing the old way of providing ‘policy-based evidence selection and interpretation’.”​

He said that the new transparency guidelines were a step in the right direction but noted much would depend on implementation, suggesting committees should be open to the public and the documentation reviewed by EFSA should be available in the public domain in advance of relevant meetings.

“It is too soon to tell whether or not EFSA will fully implement the recently announced changes in relation to ‘transparency’ or whether they will be sufficient.”​

Professor Millstone added: “Unless all commercial and institutional conflicts of interest are eradicated, the transparency provisions alone will not be sufficient.”​

EFSA rebuffs accusation

EFSA rejected the suggestion that its evaluation failed to consider all the evidence fairly and insisted that it's conclusions were the result of intensive scrutiny.

“EFSA’s opinion represents one of the most comprehensive risk assessments of aspartame ever undertaken. After a review of all available scientific data and consumption information, EFSA concluded that aspartame and its breakdown products are safe for human consumption at current levels of exposure," ​a spokesperson insisted.

According to EFSA, its review of aspartame was published following two public calls for data, which made available a 'large body of scientific information', comprising both published and previously unpublished data and studies.

EFSA received over 200 comments during the consultation on its draft opinion, which took place from 9 January 2013 to 15 February 2013. According to the safety body 'all of these were considered'.

During the consultative phase, EFSA revealed it also held a hearing with 'interested parties' to discuss the draft opinion and the feedback received from the online public consultation. EFSA’s dialogue with stakeholders revealed that there were 'important aspects' of the draft opinion that needed to be clarified in the final output.

A spokesperson for EFSA told FoodNavigator that the decision of whether or not to suspend aspartame was at the discretion of the EC.

'Aspartame is safe': ISA

The International Sweeteners Association responded to the Millstone and Dawson research with a strongly worded statement insisting: "Aspartame is safe."​

The ISA, which represents the interests of the sweeteners industry, pointed to scientific opinions from food safety authorities around the world. These, in line with what the ISA said was an 'overwhelming body of scientific evidence', have 'consistently confirmed that aspartame is safe', the trade body insisted.

"As for all low calorie sweeteners, and prior to being approved for use on the market, aspartame has been subject to extensive safety assessments. The conclusions of the European Food Safety Authority (EFSA) Scientific opinion on aspartame, published in December 2013, reconfirmed that aspartame is not a safety concern. The EFSA opinion on aspartame represents the most comprehensive assessment of the aspartame safety database that has ever been undertaken, examined by leading scientists from across Europe. Based on those data, EFSA’s experts could rule out any potential risk of aspartame causing damage to genes or to the brain.​

"Used in foods, beverages and tabletop sweeteners, low calorie sweeteners including aspartame can provide people with a wide choice of sweet-tasting options with low or no calories, and thus can be a useful tool, when used in place of sugar and as part of a balanced diet, in helping reduce overall sugar and calorie intake, as well as in managing blood glucose levels. Low calorie sweeteners are also non-cariogenic, which means that they do not contribute to tooth decay."​

Source ​

Archives of Public Health

'EFSA’s toxicological assessment of aspartame: was it even-handedly trying to identify possible unreliable positives and unreliable negatives?'​

DOI: https://doi.org/10.1186/s13690-019-0355-z

Authors: Erik Millstone and Elisabeth Dawson