Aspartame in diet soda: Why the cancer warning is misleading

A claim saying ‘aspartame is a potentially cancer-causing carcinogen’ and that the World Health Organization (WHO) is considering 'putting labels on aspartame' is misleading, and the post tends to spread fear. The post tends to spread fear as the claim has resurfaced on social media platforms, raising concerns around consuming diet coke and soda, which has aspartame as a primary artificial sweetener. Read Full Story This claim stems from the fact that the World Health Organization’s (WHO) cancer research arm, the International Agency for Research on Cancer (IARC), classified the artificial sweetener aspartame as “possibly carcinogenic to humans” in 2023. Calling aspartame carcinogenic is misleading. Let’s understand why? The risk assessment agency, the Joint Expert Committee on Food Additives (JECFA), specified that the daily acceptable intake is 40 mg/kg body weight. A can of diet soft drink usually contains 200-300 mg of aspartame. So, an adult weighing 60 kg would need to consume more than 8–12 cans per day to exceed the acceptable daily intake. One needs to understand that IARC reviews studies done on a given product and determines how strong the evidence links to cancer. It evaluates evidence on the causes of cancer but does not make health recommendations. ‘IARC RANKING IS MISREAD.' The IARC grades products and labels them as Group 1 (carcinogenic), Group 2A (probably carcinogenic), Group 2B (possibly carcinogenic) and Group 3 (not classifiable). McGill University's blog post separating sense from nonsense explains that “when something gets listed in Group 2B as possibly carcinogenic, it means that human data is lacking or inadequate and the agency is making an extrapolation from animal or in vitro lab data.” “The IARC cancer classification is one of the most misread pieces of science in the world," said Dr Jayesh Sharma, a renowned oncologist based in Raipur. He explains that a fire investigator can confirm that a matchstick is capable of starting a house fire. But whether a matchstick in your kitchen drawer will burn your house down tonight is not an absolute possibility. So, IARC does hazard identification. It does not do risk assessment. “Group 2B means there is limited evidence this agent could cause cancer in humans. The statement indicates scientific uncertainty, not a warning to throw away your diet soft drinks," said Dr Sharma. Dr Meenu Walia, Chairman – Medical Oncology, Max Super Speciality Hospital, Delhi, said that “limited evidence is a scientific language to highlight that some studies noticed something, but evidence was not enough to draw concrete conclusions.” WHAT DO FOOD SAFETY AUTHORITIES SAY? The United States Food and Drug Administration has analysed how many packets of artificial sweetener a person can consume and still be at the safe level. It highlighted that they are safe for the general population under certain conditions of use. In fact, aspartame is one of the most studied food additives in the human food supply. Since aspartame is 200 times sweeter than sugar, it is used in smaller amounts to achieve the same level of sweetness as sugar. “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,” said Dr Moez Sanaa, WHO’s Head of the Standards and Scientific Advice on Food and Nutrition Unit. “The world's leading food safety authorities, including the U.S. FDA, the European Food Safety Authority, and JECFA, continue to say aspartame is safe when consumed within established limits," said Dr Walia. She added that these conclusions aren't based on a handful of recent studies, they reflect decades of research across toxicology, metabolism, and large-scale population data.” Ends Published By: Nabeela Khan Published On: May 20, 2026 17:51 IST