Assessments of the health impacts of the non-sugar sweetener aspartame have led to disagreements among various research and public health groups.

The International Agency for Research on Cancer (IARC), the World Health Organization (WHO), and the Food and Agriculture Organization of the United Nations (FAO) and the Joint Expert Committee on Food Additives (JECFA) released their aspartame hazard and risk assessment results Friday. The IARC classified aspartame as “possibly carcinogenic to humans” because of “limited evidence” for carcinogenicity in humans. Meanwhile, the JECFA reaffirmed the acceptable daily intake of 40 mg/kg body weight for aspartame.

The U.S. Food and Drug Administration has issued a response to the recent assessments. While the IARC classified aspartame as “possibly carcinogenic to humans,” the FDA maintains that there is no evidence linking the artificial sweetener to cancer.

Aspartame, an artificial sweetener widely used in various food and beverage products since the 1980s, has become a topic of concern due to its potential health effects. It is commonly found in diet drinks, chewing gum, gelatin, ice cream, dairy products such as yogurt, breakfast cereal, toothpaste, and even medications such as cough drops and chewable vitamins.

Dr. Francesco Branca, Director of the Department of Nutrition and Food Safety at the World Health Organization (WHO), emphasized the importance of understanding potential factors contributing to cancer and the need for further studies. “The assessments of aspartame have indicated that, while safety is not a major concern at the doses which are commonly used, potential effects have been described that need to be investigated by more and better studies,” he stated.

The IARC and JECFA conducted separate evaluations of aspartame, considering its potential carcinogenic hazard and other health risks. IARC classified aspartame as “possibly carcinogenic to humans” based on limited evidence for cancer in humans, experimental animals and possible mechanisms for causing cancer. On the other hand, JECFA reaffirmed the acceptable daily intake (ADI) of 40 mg/kg body weight and concluded that aspartame consumption within this limit is safe.

Addressing the IARC’s classification, Dr. Mary Schubauer-Berigan of the IARC Monographs program acknowledged the need for more research to refine understanding regarding aspartame’s potential carcinogenic hazard. Meanwhile, Dr. Moez Sanaa, WHO’s Head of the Standards and Scientific Advice on Food and Nutrition Unit, stressed the necessity for further studies on mechanistic pathways relevant to insulin regulation, metabolic syndrome and diabetes, particularly in relation to carcinogenicity.

In response to the external safety reviews, the FDA expressed disagreement with the IARC’s conclusion, citing significant shortcomings in the studies relied upon. The FDA’s own scientists reviewed the scientific information provided by the IARC in 2021 and found no safety concerns when aspartame is used under approved conditions. The regulatory and scientific authorities of various countries, including Health Canada and the European Food Safety Authority, have also deemed aspartame safe at currently permitted use levels.

The FDA recognizes that some consumers rely on products containing aspartame and other sweeteners to reduce their sugar consumption. In order to assist consumers in making informed choices, the FDA will continue to provide reliable, science-based information on aspartame and other sweeteners on its website.