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Aspartan is used as a sugar substitute – in soft drinks, chewing gum or even in coffee

Photo: Hendrik Schmidt / dpa

A sweetener commonly used in soft drinks, yoghurt and chewing gum can cause cancer in humans, according to a new expert classification – but in the usual amounts consumed, it should not be a problem.

It is about aspartame, one of eleven sweeteners approved in the EU.

The World Health Organization (WHO) is not changing its guidelines despite the new classification. She sees no evidence in the underlying studies that consumption within the recommended maximum levels could be dangerous. According to the current state of knowledge, those who adhere to this do not expose themselves to a higher risk of cancer, the WHO reported.

"A soft drink every now and then, or chewing gum: you shouldn't worry about that," said Francesco Branca, director of the WHO's Department of Nutrition and Food Safety. "We don't recommend that consumers avoid sweeteners altogether, but we do recommend restraint." If you are considering whether to buy soft drinks with sugar or sweetener in the supermarket, it is best to consider a third option, Branca said: "Drink water" – or other drinks without sweeteners.

The new classification as "possibly carcinogenic" for aspartame comes from the International Agency for Research on Cancer (IARC) in Lyon. It belongs to the WHO. The IARC published its findings on Friday in the journal "The Lancet Oncology". In three studies involving humans, she saw limited evidence of a link with a specific form of liver cancer (hepatocellular carcinoma).

  • You can read the original »Lancet« study here: Carcinogenicity of aspartame, methyleugenol, and isoeugenol

It is important to know that the IARC experts only assess whether a substance could in principle cause cancer. They don't take into account how much of it a person would have to consume to have a risk of disease, Mary Schubauer-Berigan explained. She heads the IARC Monographs programme, which is responsible for classification.

At what level is there a risk?

Risk analyses for humans are carried out by other institutions, such as the Committee on Food Additives of the WHO and the United Nations Food and Agriculture Organization (JECFA) – or food safety authorities such as the German Federal Institute for Risk Assessment (BfR).

The maximum recommended amount of aspartame is 40 milligrams per kilogram of body weight per day. A person weighing 70 kilograms would only reach the limit if he drinks nine to 14 doses of conventional size with a diet drink with a high aspartame content in one day, the WHO reported.

Among hundreds of cancer studies involving humans, the IARC experts found three that deal with the effects of sweeteners. They also reviewed studies with mice and rats. However, all studies had certain deficiencies in the assessment of aspartame, they admitted. Therefore, the IARC emphasizes that the evidence is limited.

According to Schubauer-Berigan and Branca, the new classification is a call to science. More studies are urgently needed.