Providers newsletter

Aspartame and Cancer: Understanding the “Possibly Carcinogenic” Classification


Aspartame’s recent classification as a possibly carcinogenic substance reignited the scientific debate on its risks to health. This artificial sweetener of chemical origin has been used for decades in products as popular as Diet Coke.

The International Agency for Research on Cancer (IARC), World Health Organization (WHO), and Food and Agriculture Organization (FAO) report that there is evidence, “although limited,” on its carcinogenicity in humans, and that “acceptable daily intake of this product should be limited to of 40 mg/kg body weight.”

This is the third time these agencies have analyzed this substance for components that affect health.

In 2013, the European Food Safety Authority (EFSA), which regulates additives consumed throughout the European Union, determined that aspartame is “safe for human consumption at current levels of exposure.” For the time being, it has not changed its conclusion.

Although the American Cancer Society does not determine whether an ingredient or substance is carcinogenic, it did state that “the results of epidemiologic studies [...] of possible links between aspartame and cancer (including blood-related cancers) have not been consistent for most cancers. Some studies have suggested a possible link, but others have not.”

The WHO explains that aspartame is an artificial sweetener (of chemical origin) that has been widely used to sweeten tea, coffee, and other foods and beverages since the 1980s.

It is used in the production of diet drinks, chewing gum, gelatin, ice cream, dairy products such as yogurt, breakfast cereals, toothpastes, and medications like cough drops and chewable vitamins.

To put aspartame consumption in perspective, the Food and Drug Administration (FDA), which regulates these substances, has determined that the “acceptable daily intake” of aspartame is 40-50 mg/kg (1 kg=2.2 lb). This means that a person weighing 60 kg (132 lb) would have to consume 75 packets of aspartame in one day to reach the safe use limit.

“Cancer is one of the leading causes of death globally. Every year, 1 in 6 people die from cancer. Science is continuously expanding to assess the possible initiating or facilitating factors of cancer, in the hope of reducing these numbers and the human toll,” said Dr. Francesco Branca, Director of the Department of Nutrition and Food Safety of the WHO, at a press conference.

“The assessments of aspartame have indicated that [... its] potential effects [...] need to be investigated by more [...] studies,” she added.

Aspartame has only been determined to be dangerous for people with phenylketonuria, a rare inherited disorder that causes an amino acid called phenylalanine to build up in the body. Phenylalanine is one of the ingredients in aspartame. That is why products with aspartame must contain a warning on the label.

For the general population, Branca said that the substance should concern heavy consumers of diet soda and other aspartame-containing products. If it is used at a level below what’s recommended, it will probably not be a problem.

But Branca added that we need to protect children from these flavors. She recommended that children drink water when they are at the stage in life when they develop their sense of taste, so they don’t get used to artificial flavors.

The WHO has identified 300 products, foods, and even trades as “possibly carcinogenic.”

This story was produced using content from original studies or reports, as well as other medical research and health and public health sources cited in links throughout the article.