WHO to classify aspartame sweetener as a potential carcinogen

The low-calorie artificial sweetener commonly used in a range of food and drink products, like Diet Coke, could be in for a rocky ride.
Mrigakshi Dixit
This sweetener is widely used in products such as Diet Coke.
This sweetener is widely used in products such as Diet Coke.


The World Health Organization (WHO) is likely to designate a common sweetener as possibly carcinogenic in July. According to Reuters, this move is expected to ignite a major row between industry and regulators. 

Aspartame is an artificial non-saccharide sweetener that is. 200 times sweeter than sucrose and is commonly used as a sugar substitute in foods and beverages, including Diet Coca-Cola, Fanta Zero and Mars' Extra chewing gum. 

The WHO's cancer research wing, the International Agency for Research on Cancer (IARC), has found that the substance is "possibly carcinogenic to humans." IARC stated at the June review meeting that the evaluation is based on 1,300 studies.

“The IARC ruling, finalized earlier this month after a meeting of the group's external experts, is intended to assess whether something is a potential hazard or not, based on all the published evidence,” Reuters reported. 

Daily consumption limits

In 1981, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) ruled aspartame was safe for human consumption, only when consumed under daily limits.

For example, a 60kg-adult (132 pounds) would need to drink roughly 12 to 36 cans of diet soda each day to be at risk of developing cancer. This is also dependent on the levels of aspartame in the diet Coke can. 

Reuters adds that these estimates have been mostly kept into account by national regulators, including those in the United States and Europe.

However, the IARC has not yet disclosed how much aspartame used per day is safe for a person. 

The IARC has previously attracted criticism for issuing "confusing rulings" on various substances; for example, it earlier said that consuming red meat and mobile phone use could potentially cause cancer.

The latest IARC assessment has divided experts once again. 

The International Sweeteners Association (ISA) expressed concern about the review shortly after the announcement.

"IARC is not a food safety body and their review of aspartame is not scientifically comprehensive and is based heavily on widely discredited research,” secretary general of the ISA Frances Hunt-Wood told Reuters.

Many well-known beverage companies are members of ISA, including Coca-Cola and Pepsico. 

Meanwhile, JECFA is investigating the usage of aspartame and is due to release its findings on July 14 — mostly likely along with the IARC.

Scientific study on aspartame

The use of artificial sweeteners in food products, and the health hazards associated with them, have been researched in recent years. 

In 2022, an observational study on 100,000 individuals in France found that those who consumed high doses of artificial sweeteners (including aspartame) in food products had a slightly increased chance of developing cancer. 

The study was derived from a study conducted on rats in the 2000s. The Ramazzini Institute in Italy led this study and found that aspartame was associated with some cancers in mice and rats.

However, according to Reuters, these studies were unable to give conclusive evidence that aspartame consumption raised cancer risk.