Sweetener: Aspartame is “possibly carcinogenic”

It is in soft drinks, light products or ready meals. The WHO has now classified the sweetener aspartame as “possibly carcinogenic”. What does that mean? And how dangerous is the artificial sweetener?

What was decided?

The cancer research agency IARC of the World Health Organization (WHO) has classified the sweetener aspartame as “possibly carcinogenic”. The decision was taken after a meeting of external experts from the group.

The IARC has a total of four different classification levels – carcinogenic, probable carcinogenic, possibly carcinogenic and unclassifiable. The levels are based on the strength of the evidence and not on how dangerous a substance is. The IARC classifies red meat, hot drinks over 65 degrees or night work in the “probably carcinogenic” category. The “high-frequency electromagnetic fields” associated with the use of mobile phones are classified as “possibly carcinogenic”.

In addition, the WHO expert committee on food additives (JECFA) reconfirmed the previously permissible daily dose of 40 milligrams of aspartame per kilogram of body weight.

What is aspartame?

Aspartame is a sweetener. Because it’s about 200 times sweeter than sugar, you only need small amounts of it. Under the abbreviation E 951, it can be found in light soft drinks, desserts, confectionery, dairy products, chewing gum, low-calorie products and weight control products. In the EU, a product’s label must state if it contains aspartame.

The sweetener has been extensively studied for decades. In 2013 the European Food Safety Authority came along EFSA to the conclusionthat “aspartame and its breakdown products are safe for the general population (including infants, children and pregnant women)”. Currently, an acceptable daily intake of up to 40 milligrams per kilogram of body weight per day is considered harmless. For comparison: a liter of Diet Coke contains around 130 milligrams of aspartame.

What is the study situation on cancer risk?

“It’s not clear,” says Jutta Hübner, an oncologist at Jena University Hospital, “although research has been going on for decades.” Last year, a large study from France with 100,000 participants made headlines. She found that people who consumed larger amounts of artificial sweeteners – including aspartame – had a slightly increased risk of cancer. “However, this study has significant methodological shortcomings, which is why it is not very informative,” says Hübner.

dr Stefan Kabisch, from the German Center for Diabetes Research, told the science platform Science Media Center that the classification of aspartame as ‘possibly carcinogenic’ is unlikely to change anything in our daily use. “The classification is very conservative, which means that a cancer risk is by no means certain and not even particularly probable. Therefore, the recommended maximum daily dose does not change.”

IARC said it assessed 1,300 studies in its June review. However, according to Hübner, other risk factors that can cause cancer were not sufficiently taken into account in the vast majority of studies. “That’s why I find IARC’s decision difficult,” explains the doctor tagesschau.de.

What role does the dosage play?

Hübner emphasizes that this is an important question, especially when it comes to everyday food. “Any substance can cause cancer. It’s always a question of the dose.” In normal daily amounts, the expert considers the risk to be low. “I also drink a bottle of light cola without hesitation or put a sweetener tablet in my tea,” says the oncologist.

The expert committee JECFA has also considered the consumption of aspartame within the accepted daily amounts to be safe since 1981. This assessment is largely shared by national regulators, including those in the US and Europe.

However, Hübner reports a trend in which cancer patients avoid sugar for fear that it will make cancer cells grow faster and instead consume more sweeteners. However, this is not correct, since such “cancer diets” could have negative effects on the course of the disease. The German Cancer Research Center DKFZ also writes: “For cancer patients, a balanced diet with all nutrients – including sugar and carbohydrates in general – is extremely important.”

Metabolism doctor Kabisch adds: “It is to be hoped that the new classification will be received calmly and will not cause consumers to switch from sweeteners to sugar. There is no solid reason to actively avoid sweeteners, but there is also no reason to actively recommend sweeteners. The benefit is small, the damage not clearly provable.”

How (un)healthy are aspartame and other sweeteners in general?

Sweeteners are a popular way to reduce sugar in foods. But they have been criticized for a long time. On the one hand, according to the WHO, they are not suitable for losing weight. Studies have shown that this can help in the short term to lose weight or not to gain weight. However, long-term use increases the risk of weight gain and obesity, according to a new study guideline the WHO. In adults, long-term consumption was associated with an increased risk of type 2 diabetes and cardiovascular diseases, among other things.

In addition, sweeteners are suspected of damaging the intestinal flora. So one showed Study 2021 that, among other things, aspartame can have a negative effect on intestinal bacteria. Some were able to cross the intestinal wall as a result. If they get into the bloodstream or other organs, they could cause infections there, the authors said.