New research casts doubts on widely used aspartame sweetener

22 Jul 2019 --- The world’s “most widely used” artificial sweetener has not been adequately proven to be safe for human consumption, argues a newly published paper from University of Sussex researchers. The team detailed serious flaws in the reassurance provided in 2013 by the European Food Safety Authority (EFSA) about the safety of aspartame – more commonly known as Nutrasweet. The researchers warn that the food industry needs to progressively diminish the sweetness of its products, rather than shifting to sweeteners.

In response to the study, the International Sweeteners Association (ISA) released a statement which points to scientific opinions from food safety authorities around the world which, in line with the overwhelming body of scientific evidence available, “have consistently confirmed that aspartame is safe.” It further highlights that the EFSA opinion in question “represents the most comprehensive assessment of the aspartame safety database that has ever been undertaken.”

“The paper is both important and timely. The global health advice is to reduce sugar intake, yet much of the food industry – especially soft drinks – maintains the sweetness by substituting artificial sweeteners. Millstone and Dawson help expose that strategy for what it is – a continued sweetening of the world’s diet. The healthy strategy should be to tackle the cultural reinforcement of sweetness and to encourage less sweet foods and drinks, full stop. Surely we now argue: reduce both sugar and artificial alternatives,” says Tim Lang, Professor of Food Policy at City, University of London, who was not involved in the research.

Since 1974, some studies and scientists have warned of the risks of brain damage, liver and lung cancer, brain lesions and neuroendocrine disorders from consuming Nutrasweet, which is found in thousands of products around the world including diet soft drinks.

The food industry should move away from substituting sugar with artificial sweeteners, note the researchers.The new study points out the EFSA panel discounted the results of 73 studies that indicated that aspartame could be harmful while treating 84 percent of studies providing no prima facie evidence of harm as “unproblematically reliable.”

However, in response to the study EFSA shared with NutritionInsight, “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.”

Professor Erik Millstone, a University of Sussex expert on food chemical safety policy, is calling for the suspension of authorization to sell or use aspartame in the EU pending an independent and thorough re-examination of relevant evidence – including key documents that Millstone says were omitted from the dossier the panel reviewed.

He is also advocating a radical overhaul of EU food safety processes including an end to behind-closed-door discussions.

Millstone explains that their analysis of the evidence shows that the panel could have been obliged to conclude that aspartame is not acceptably safe. This is because the benchmarks used by the panel should have been consistently used to evaluate the results of studies providing evidence that aspartame may be unsafe, instead of just using the benchmarks for reassuring studies.  

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

Millstone contributed a 30 document dossier to the 2013 proceedings detailing the inadequacy of 15 early pivotal studies which, he says, the EFSA failed to pass on to its scientific advisors. He notes that it is clear from the research that the EFSA scientists “failed to acknowledge numerous inadequacies in the reassuring studies. Instead, they picked up on tiny imperfections in all the studies providing evidence that aspartame may be unsafe.”

“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 the meetings all took place behind closed doors,” he adds.

Millstone tells NutritionInsight that the next steps will be the EFSA Board (in collaboration with DG-Sante at the European Commission) ensuring that no members of the Board, its scientific committee or any of its scientific panels, have any commercial conflicts of interest. He also calls for all EFSA expert meetings to be open to the public, as practised by the UK Food Standards Agency (FSA).

“EFSA must abandon its rhetorical narrative that ‘an interest is not necessarily a conflict of interest.’ All the recently introduced provisions regarding transparency of EFSA’s work need to be fully implemented, and all EFSA panels need to show that, when they are assessing the possible risks of dietary ingredients, they are at least as careful to avoid ‘false negatives’ as ‘false positives,’” he explains.  

Among the flaws in the study highlighted by the University of Sussex research, were:

• The panel breached EFSA guidelines on risk assessment transparency on multiple grounds.
• It adopted a low-hurdle for the acceptability of negative studies –  including studies previously dubbed “woefully inadequate” and “worthless” by experts.
• It applied unreachable high hurdles for “positive” studies indicating adverse effects – even though many of those 73 studies were far more reliable than most of the studies that provided no indication of risk.
• It demonstrated “puzzling anomalies” including inconsistent and unacknowledged assumptions. 

NutritionInsight has reached out to the EFSA for comment on the study.

The use of sweeteners has increased in recent years, in part driven by rising consumer awareness on the adverse health outcomes relating to high sugar consumption, as well as sugar taxes driving product reformulation. This is also stimulating NPD as industry is turning towards alternatives to keep up with the demand for sugar-free, yet just as sweet, formulations. 

However, the use of certain sweeteners has been closely watched, with some flagging potential health concerns. Last year, a paper published in Molecules claimed that US FDA-approved artificial sweeteners and sports supplements were found to be toxic to digestive gut microbes.

Meanwhile, a study published in February noted that non-caloric sweeteners have a negligible effect on the gut microbiome and are not significantly linked to cancer and diabetes risk, as long as their consumption is in line with the ADI (Acceptable Daily Intake) recommended intake. 

By Laxmi Haigh