In an unprecedented move, the International Agency for Research on Cancer (IARC) and the Joint Expert Committee on Food Additives (JECFA) of the World Health Organization (WHO) and Food and Agriculture Organization (FAO) released health impact assessments of aspartame, a non-sugar sweetener widely used in various food and beverage products.

Based on “limited evidence,” the IARC classified aspartame as possibly carcinogenic to humans, placing it in Group 2B. This classification is generally used when there is limited, albeit unconvincing, evidence for cancer in humans or convincing evidence for cancer in experimental animals, but not both. Meanwhile, the JECFA reaffirmed the acceptable daily intake of aspartame to be 40 mg/kg body weight.


Aspartame, an artificial sweetener, has been a common ingredient in products like diet drinks, chewing gum, gelatin, ice cream, dairy products such as yogurt, breakfast cereal, toothpaste, and medications such as cough drops and chewable vitamins since the 1980s. The potential health risks have long been debated, and this is the first time that the IARC has evaluated aspartame and the third time for JECFA.

The evaluations found limitations in the available evidence for cancer and other health effects, with a specific focus on hepatocellular carcinoma, a type of liver cancer. The IARC and JECFA independently but complementarily reviewed scientific literature, performed hazard identifications, and factored in all types of exposures. The evidence on potential carcinogenicity was classified as limited in both humans and animals, requiring further research to refine the understanding of aspartame’s carcinogenic hazard.

Soft drinks

Despite the classification, JECFA concluded that there is no sufficient reason to alter the previously established acceptable daily intake (ADI) of 0–40 mg/kg body weight for aspartame. An adult weighing 70kg would need to consume more than 9–14 cans of diet soft drink, each containing 200 or 300 mg of aspartame, per day to exceed the acceptable daily intake, assuming no other intake from other food sources.

Dr. Moez Sanaa, WHO’s Head of the Standards and Scientific Advice on Food and Nutrition Unit, stated, “JECFA also considered the evidence on cancer risk, in animal and human studies, and concluded that the evidence of an association between aspartame consumption and cancer in humans is not convincing.” Dr. Sanaa emphasized the need for better studies with longer follow-up, including randomized controlled trials.

These assessments mark a critical step in evaluating aspartame’s potential health impacts and a move towards more robust and comprehensive investigations. The WHO and IARC have committed to continue monitoring new evidence and encouraging independent research groups to conduct further studies on aspartame’s potential health effects.