four questions about the WHO’s decision to classify this sweetener as “possibly carcinogenic”

This small white powder makes it possible to dispense with sugar, while retaining its taste. Aspartame has imposed itself everywhere on our plates and in our glasses, in a few decades. However, this product has just been classified as being “possibly carcinogenic to humans”Friday, July 14, by the World Health Organization (WHO). Franceinfo deciphers the reasons for this classification and its consequences.

1 What is aspartame?

Aspartame is a synthetic sweetener. Its properties were discovered by chance in 1965 by a chemist, then in search of a treatment against ulcers, explains Santé.fr. The particularly sweetening power of aspartame attracts attention: it is 200 times higher than our ordinary sugar. The properties of this white and odorless powder quickly make it an interesting product for the food sector. Although it has no nutritional value, it was first approved for consumption in the US market by the Food and Drug Administration in 1974.

France authorized it fourteen years later and waited until 1994 to accept its use as a sweetener in foodstuffs. Aspartame is now present in “light”, “light” or “0%” products and drinks, as well as in certain medicines, such as cough drops.

2Since when is it suspected of being a carcinogen?

Suspicions arose immediately after its authorization on the American market. Its use was suspended after several months of marketing, due to doubts about possible toxic and carcinogenic effects. Aspartame was again authorized in the United States in 1981, first in solid foods and then, two years later, in liquids. But, in Europe, researchers have continued to investigate the possible carcinogenic consequences of this “fake sugar”.

In December 2013, the European Food Safety Authority brushed aside concerns, assuring that aspartame was safe, provided the recommended daily dose of 40 milligrams per kilogram of body weight was respected. Two years later, the French Food Safety Agency (ANSES) affirmed that no data made it possible to demonstrate a proven risk of cancer, while emphasizing “the need to deepen knowledge” on aspartame. In March 2022, a study conducted by French researchers linked its consumption, like other sweeteners, to an increased risk of cardiovascular disease.

3What are the conclusions of the WHO?

The decision to place aspartame as a possible carcinogen was made on the basis of “limited guidance“relating to cancer in humans, particularly for hepatocellular carcinoma, a type of liver cancer, according to the WHO. Limited evidence has also been seen for cancer in laboratory animals. These indications “come from three studies conducted in the United States and ten European countries. These are the only epidemiological studies on liver cancer“, said Mary Schubauer-Berigan, PhD at the WHO’s International Agency for Research on Cancer (IARC). A total of 1,300 studies, conducted in several countries, have been scrutinized by the WHO.

Twenty-five scientists, of a dozen different nationalities, then met from June 6 to 13, at the International Agency for Research against Cancer, in Lyon. They assessed the level of dangerousness of aspartame and other sweeteners. At the end of this meeting, this additive was classified 2B, i.e. as being “possibly carcinogenic to humans”.

This category means that there is evidence “limited of a risk in humans” And “insufficient in laboratory animals”. Are listed, in this same category, exhaust gases, in the same way as aloe vera in certain forms or caffeic acid, present in many plants, including sage or cinnamon. The WHO could have classified aspartame as “probably carcinogenic” whether the evidence was sufficient in animals. For comparison, a ranking of 1 means that the agent is “carcinogenic” for the human. This is particularly the case with tobacco, UV rays or alcohol.

On Friday, the Joint Expert Committee on Food Additives (which is part of both the WHO and the FAO), issued its own conclusions on the risks associated with aspartame. Its members considered that the current data did not justify changing the acceptable daily intake. Unchanged since 1981, this maximum of 40 milligrams per kilogram of body weight is difficult to achieve. For example, if a “light” soda is used as the unit of measurement, a 68 kg person would have to drink more than a dozen cans a day before exceeding this limit.

4Should we stop taking aspartame?

“We are not advising companies to withdraw their products, nor are we advising consumers to completely stop using them”said the director of the WHO’s Department of Nutrition, Health and Development.

By presenting these two evaluations on aspartame, doctor Francesco Branca wanted to be reassuring: “The problem arises for large consumers” of products containing this sweetener. “Our results do not indicate that occasional consumption poses a risk.” A declaration quickly denounced by the European association Foodwatch: “A possibly carcinogenic sweetener has no place in our food or drink.”

By the end of the year, Europeans will in any case be encouraged to consume less aspartame since the Nutri-Score calculation methods will be modified. The notes of foods and drinks containing sweeteners will be degraded.

Beyond these carcinogenic risks, the WHO also spoke on Monday about the long-term consequences of regular consumption of aspartame. These types of sweeteners increase the risk, in adults, of developing type 2 diabetes and cardiovascular disease. “Use of these sugar-free sweeteners confers no long-term benefit in reducing body fat in adults or children”finally specifies the world agency, based solely on observational studies.