The World Health Organization (WHO) declared the sugar substitute aspartame to be “possibly carcinogenic to humans,” but it is not recommending any changes to its consumption levels. For decades, the acceptable daily intake (ADI) of the non-sugar sweetener has been 40 mg per kg of body weight. That remains unchanged, the WHO said in a joint statement by its cancer research arm and the Food and Agriculture Organization (FAO) yesterday (July 13).
Researchers say there is still “limited evidence” for carcinogenicity of the ubiquitous ingredient, which is used in around 6,000 products, products ranging from chewing gum to yogurt to diet sodas. They recommended “more and better” studies with “longer follow-ups” to establish evidence of carcinogenicity, and how it occurs.
While the WHO, a UN agency tasked with assessing international public health, does not have the authority to make rules—that’s a job for national regulators such as the Food and Drug Administration’s (FDA) in the US—its advice can influence public perception and policy. With no tweaks to the consumption reactions, the industry can breathe easy for now.
The American Beverage Association, which lobbies on behalf of Coca-Cola, Pepsi, and Keurig Dr Pepper, heralded the WHO’s guidance as confirmation of the sweetener’s safety. “With more than 40 years of science and this definitive conclusion from the WHO, consumers can move forward with confidence that aspartame is a safe choice, especially for people looking to reduce sugar and calories in their diets,” it said in a statement on July 13.
For beverage giants, the aspartame scrutiny does not have a huge impact on the bottom line. Diet soda comprises less than a quarter of the market that’s still dominated by regular soda.
A drastic change to the guidance could possibly have hurt sales, or lead to reworking drink formulas. Lower-calorie sodas without aspartame do exist. While the likes of Pepsi Zero Sugar, Diet Coke, and Coke Zero still contain the sweetener, PepsiCo already ditched aspartame from Diet Pepsi in 2020.
9-14: Cans of diet soft drink containing 200 or 300 mg of aspartame that an adult weighing 70 kg would need to consume in a day to exceed the acceptable daily intake, assuming no other intake from other food sources.
“Faced with a decision of whether to take cola with sweeteners or one with sugar, I think there should be a third option, which is to drink water instead and to limit the consumption of sweetened products altogether.”—Francesco Branca, the director of the department of nutrition and food safety at the World Health Organisation (WHO), told the BBC after the advisory was published.
- Group 1 - Carcinogenic (cancer causing) to humans
- Group 2A - Probably carcinogenic to humans
- Group 2B - Possibly carcinogenic to humans. The category aspartame has been assigned to also includes aloe vera, progesterone-only contraceptives, radiofrequency magnetic fields, naphthalene, and even entire professions like carpentry and dry cleaning
- Group 3 - Not classifiable
1969: Pharmaceutical company G.D. Searle & Co. (Searle) conducts a safety testing program to collect data to submit a food additive petition on aspartame, a sweetener that is is 200 times sweeter than sugar.
July 1974: The FDA first approves aspartame as a tabletop food sweetener and in chewing gum, cold breakfast cereals, and dry bases for certain foods (for example, beverages, instant coffee and tea, gelatins, puddings and fillings, and dairy products and toppings). It also establishes a safe level of consumption from long-term toxicology studies.
August 1974: The FDA receives objections that phenylalanine in aspartame could lead to convulsions and intellectual disabilities. Following the allegations, the FDA probes Searle’s studies and its task force concludes some of the research was questionable, putting the aspartame regulation on hold so it can’t be marketed.
August 1977: After scrutinising a gamut of rat, mouse, dog, and monkey studies, FDA scientists conclude that the discrepancies did not compromise the data.
October 1980: A Public Board of Inquiry (PBOI) revokes the 1974 aspartame approval, concluding that more studies were needed to determine whether aspartame caused brain tumors.
April 1981: The Joint FAO/WHO Expert Committee on Food Additives (JECFA) establishes 40 mg/kg body weight as the acceptable daily intake (ADI) for aspartame.
July 1981: The FDA’s Commissioner overturns the PBOI decision and the marketing of aspartame in dry foods is allowed.
July 1983: The FDA approves the use of aspartame in carbonated beverages. The limit is revised to 50 mg/kg body weight.
May 1984: The FDA approves the use of aspartame in multivitamins.
November 1986: The FDA approves aspartame’s use in fruit juices, stick-type confections, breath mints, and iced tea.
December 1986: The FDA declares aspartame safe as an inactive ingredient in drugs, and approves the use of aspartame in ready-to-serve gelatin desserts.
June 1987: All this while, the FDA has been receiving and dismissing a spate of objections to its approvals. The Government Accountability Office (GAO) concludes the FDA adequately followed its food additive approval process in greenlighting aspartame for marketing.
October 1988: The FDA allows aspartame in the filling of pre-baked cookies.
June 1989: The FDA permits the use of aspartame in frozen ready-to-thaw-and-eat cheesecake, fruit and fruit toppings; and frozen dairy and nondairy frostings, toppings, and fillings.
January 1992: The FDA approves aspartame for marketing in a bulk package, for hot and instant cereals, and for refrigerated and ready-to-serve puddings.
April 1993: The FDA approves aspartame for use in hard and soft candy, additional non-alcoholic beverages, and beer with less than 3% alcohol.
June 1996: The FDA approves the use of aspartame as a general-purpose sweetener in response to a petition from NutraSweet (formerly Searle).
December 2005: The European Ramazzini Foundation (ERF) publishes a first aspartame carcinogenicity study.
October 2014: The FDA denies two citizen petitions that ask the agency to revoke the authorizations for aspartame.
March 2022: A French observational study with more than 100,000 subjects observes an elevated cancer risk in subjects who consume large quantities of artificial sweeter, especially aspartame.