Dusseldorf The sweetener aspartame is widespread – in diet drinks as well as in sugar-free chewing gum, low-calorie yoghurt, desserts or sweets. The World Health Organization’s International Agency for Research on Cancer (IARC) classified the white additive as “possibly carcinogenic” to humans on Friday. For the past two weeks, speculation about this has had food manufacturers and consumers around the world in turmoil.
On Friday, the WHO also made it clear that there was no convincing evidence that aspartame had any harmful effects after consumption. This is the conclusion reached by the Expert Committee on Food Additives (Jecfa). Unlike the cancer researchers at the IARC, he is allowed to make risk assessments based on actual consumption and make health recommendations.
The committee confirmed the recommended maximum daily dose of up to 40 milligrams of aspartame per kilogram of body weight. To exceed that number, a 150-pound adult would need to drink more than nine to 14 cans of diet soda a day.
However, the classification by the IARC could have legal consequences for confectionery and beverage manufacturers. In the USA, classifications by health authorities such as the IARC are regularly the basis for product liability claims. Bayer AG has recently felt this painfully: the settlement of the lawsuits in the USA because of alleged health risks from the weed killer glyphosate has already cost the company more than ten billion euros.
200 times sweeter than sugar
Aspartame was accidentally discovered in 1965 by American chemist James Schlatter. While experimenting with amino acids in search of an anti-ulcer drug, he noticed the sweet taste. The white powder has almost as many calories as sugar but is 200 times sweeter. In 1981, the sweetener was launched in the USA. Also known as Nutrasweet. Aspartame has been approved in Germany since 1990, recognizable by the E number 951.
Again and again, aspartame was suspected of being harmful to health. Most recently, a French study in 2022 linked artificial sweeteners – particularly aspartame and acesulfame-K – to an increased risk of cancer. More than 100,000 French people were examined over a period of almost eight years. However, the study is not without controversy.
The cancer researchers at the IARC have now found “limited evidence” for the carcinogenic effects of aspartame in humans – related to hepatocellular carcinoma, a form of liver cancer. This assessment is based on three studies, which, however, found an inconclusive connection between the consumption of artificially sweetened beverages and the risk of liver cancer. The IARC is now calling for further scientific studies.
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The International Sweeteners Association (ISA) reacted with relief and welcomed the decision of the WHO experts to stick to the maximum daily dose for aspartame. “More than 90 food safety authorities around the world have declared aspartame safe, including the European Food Safety Authority, which conducted the most comprehensive safety assessment of aspartame to date,” said ISA Secretary-General Frances Hunt-Wood.
Every third bottle of Coke in Germany with sweetener
Market researcher Market Data Forecast predicts that the global market for sweeteners will grow from $7.2 billion to $9.7 billion by 2028. However, sales of calorie-free or reduced-calorie drinks and snacks are many times higher. For example, every third bottle of Coke sold in Germany is a sugar-free variant that also contains aspartame. For comparison: A liter of Coke Classic contains 36 sugar cubes in this country. When asked, the world’s largest beverage company, Coca-Cola, declined to comment on the classification of aspartame as “possibly carcinogenic” and referred to the sweeteners association ISA.
The International Council of Beverage Associations emphasized: “According to IARC, aspartame poses no greater risk to consumers than aloe vera.” The extract from aloe vera leaves is also classified as “possibly carcinogenic”. Studies have shown that this causes cancer in rats, but it has not been studied in humans, explains Verena Katzke, head of the Nutritional Epidemiology working group at the German Cancer Research Center.
More than 100,000 lawsuits against glyphosate
Beverage and food manufacturers that use aspartame need to take IARC ratings seriously. Glyphosate was classified as “probably carcinogenic” in 2015, one tier higher than aspartame. This prompted several major US law firms to prepare product liability suits and recruit glyphosate users with cancer as plaintiffs. After the first lawsuits in 2018 and 2019, Bayer faced more than 100,000 lawsuits.
In the lawsuits, the IARC classification was central to the evidence for the plaintiffs’ lawyers: the Monsanto group, which had been taken over by Bayer, is said to have known that glyphosate was a cancer hazard, but did not point it out on the product label. Bayer has always rejected this and referred to the safety ratings by state testing authorities such as the American EPA or the European Food Safety Authority EFSA.
However, the classification of the IARC drew as an argument with the lay juries in the US trials. After losing three lawsuits, Bayer agreed to an out-of-court settlement of the lawsuits, which has not yet been completed.
The sweetener aspartame is classified by the IARC one level below glyphosate – i.e. as “possibly carcinogenic”. According to industry and company circles, however, American confectionery manufacturers have been asking Bayer in recent weeks how the dispute with the IARC and the lawyers was going – for fear that they, too, could be targeted by the product liability lawsuits.
Criticism of IARC classifications
Criticism of the IARC’s approach has been smoldering for some time and is likely to be further fueled by aspartame. In fact, the WHO itself sees no cancer risk from glyphosate. The IARC classifies substances only because of their basic potential cancer risk – regardless of the quantities in which they are used. This is why red meat is considered “probably carcinogenic”.
The large testing authorities, on the other hand, follow a risk-oriented approach and assess the dangers with a view to the quantities used in practice: normal consumption of red meat is not dangerous.
When it comes to aspartame, nutritionists call for prudence. “It is to be hoped that the classification does not make consumers switch from sweeteners to sugar,” says Stefan Kabisch, a study doctor at the German Center for Diabetes Research at the Berlin Charité.
For sugar, there is much clearer evidence that, in addition to caries, it also promotes obesity and type 2 diabetes and thus contributes to the risk of cancer, according to the doctor. A switch from sweeteners to sugar would certainly increase the risk of illness.
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