Home USA News Aspartame sweetener used in Diet Coke a Possible Carcinogen: WHO

Aspartame sweetener used in Diet Coke a Possible Carcinogen: WHO

Aspartame sweetener used in Diet Coke a Possible Carcinogen: WHO
Diet Coke is seen on display at a store in New York City, U.S.

The International Agency for Research on Cancer (IARC), the cancer research arm of the World Health Organization (WHO), is expected to declare aspartame, one of the most widely used artificial sweeteners, as a possible carcinogen.

This decision by the IARC has raised concerns within the food industry and among regulators. Aspartame is commonly found in various products, including diet sodas, chewing gum, and certain beverages. The upcoming classification by the IARC does not take into account the safe consumption limits but aims to assess potential hazards based on published evidence.

The IARC’s Decision and Its Impact

The IARC, comprising external experts, recently finalized its decision to list aspartame as “possibly carcinogenic to humans.” While this ruling is not a definitive declaration of harm, previous similar classifications by the IARC have led to consumer concerns, legal actions, and pressure on manufacturers to reformulate their products or seek alternatives. Some critics argue that the IARC’s assessments can be confusing to the public.

Simultaneously, the WHO’s Joint Expert Committee on Food Additives (JECFA) is also reviewing the use of aspartame this year. The findings of the JECFA, which assesses the safe levels of consumption, are expected to be released on the same day as the IARC’s decision. The coordination of both processes is crucial to avoid confusion and concerns among the public, as expressed by regulators from the United States and Japan.

Aspartame Safety and Regulatory Views

Since 1981, JECFA has stated that aspartame is safe for consumption within accepted daily limits. National regulators, including those in the United States and Europe, have largely shared this view. For example, an adult weighing 60 kg (132 pounds) would need to consume an excessive amount of diet soda daily to be at risk. However, the IARC’s classification could challenge the prevailing regulatory consensus.

Industry and Regulator Concerns

Regulators and industry stakeholders have expressed concerns about potential confusion arising from the simultaneous processes of the IARC and JECFA. The release of both conclusions on the same day aims to mitigate this confusion. The International Sweeteners Association (ISA), which includes members such as Mars Wrigley and Coca-Cola, has criticized the IARC review, calling it scientifically incomplete and based on discredited research. The International Council of Beverages Associations has also voiced concerns, emphasizing the potential impact on consumer choices and public health.

Debate and Historical Examples

The IARC’s previous decisions have had significant repercussions. For instance, its classification of glyphosate as “probably carcinogenic” in 2015 led to legal battles and financial losses for companies involved in the production of glyphosate-based weedkillers. Critics argue that the IARC’s classifications have sometimes caused unnecessary alarm, such as labeling red meat consumption and working overnight as “probably cancer-causing” or mobile phones as “possibly cancer-causing.”

Existing Research and Industry Response

Aspartame has been extensively studied, with research yielding mixed results. While an observational study in France suggested a slightly higher cancer risk associated with the consumption of artificial sweeteners, including aspartame, it could not establish a causal link. Questions have also been raised about the methodology of another study linking aspartame to cancer in animals. Regulators globally have authorized the use of aspartame based on the available evidence, and major food and beverage manufacturers have defended its use.


The upcoming classification of aspartame as a possible carcinogen by the IARC is expected to fuel further research and enable agencies, consumers, and manufacturers to draw more informed conclusions. However, it is also likely to reignite debates about the role of the IARC and the safety of sweeteners in general.

As the discussions unfold, it is important for regulators and industry stakeholders to coordinate efforts and provide clear, science-based information to the public, ensuring that any potential risks are thoroughly understood and communicated.