Aspartame – a popular sweetener used in many hudely popular products including Diet Coke – is expected to be declared a possible cancer cause by the World Health Organisation (WHO).
The International Agency for Research on Cancer (IARC), the WHO’s cancer research arm, will next month list the hugely popular sweetener as “possibly carcinogenic to humans”, said news agency Reuters citing “two sources with knowledge of the process”.
The move is expected to pit the global leading health body against the food industry and regulators, and has already drawn criticism from the sector.
The IARC ruling - finalised earlier this month after a meeting of the group’s external experts - is intended to assess whether something is a potential hazard or not, based on all published evidence.
It does not take into account how much of a product a person can safely consume. Advice on this comes from a separate WHO expert committee on food additives, known as JECFA, alongside determinations from national regulators.
However, similar IARC rulings in the past for different substances have raised concerns among consumers about their use, led to lawsuits, and pressured manufacturers to recreate recipes and swap to alternatives. That has led to criticism that the IARC’s assessments can be confusing to the public.
IARC decisions have also faced criticism for sparking needless alarm over hard to avoid substances or situations. It has previously put working overnight and consuming red meat into its “probably cancer-causing” class, and using mobile phones as “possibly cancer-causing”.
“IARC is not a food safety body and their review of aspartame is not scientifically comprehensive and is based heavily on widely discredited research,” Frances Hunt-Wood, the secretary general of the International Sweeteners Association (ISA), said.
The body, whose members include Mars Wrigley, a Coca-Cola unit and Cargill, said it had “serious concerns with the IARC review, which may mislead consumers”.
The International Council of Beverages Associations’ executive director Kate Loatman said public health authorities should be “deeply concerned” by the “leaked opinion”, and also warned it “could needlessly mislead consumers into consuming more sugar rather than choosing safe no-and low-sugar options.”
JECFA, the WHO committee on additives, is also reviewing aspartame use this year. Its meeting began at the end of June and it is due to announce its findings on the same day that the IARC makes public its decision on July 14.
Since 1981, JECFA has said aspartame is safe to consume within accepted daily limits. Its view has been widely shared by national regulators, including in the United States and Europe.
An IARC spokesperson said both the IARC and JECFA committees’ findings were confidential until July, but added they were “complementary”, with IARC’s conclusion representing “the first fundamental step to understand carcinogenicity”.
Aspartame has been extensively studied for years. Last year, an observational study in France among 100,000 adults showed that people who consumed larger amounts of artificial sweeteners including aspartame had a slightly higher cancer risk.
It followed a study from the Ramazzini Institute in Italy in the early 2000s, which reported that some cancers in mice and rats were linked to aspartame.
However, the first study could not prove that aspartame caused the increased cancer risk, and questions have been raised about the methodology of the second study, including by EFSA, which assessed it.
Aspartame is authorised for use globally by regulators who have reviewed all the available evidence, and major food and beverage makers have for decades defended their use of the ingredient. The IARC said it had assessed 1,300 studies in its June review.
Recent recipe tweaks by soft drinks giant Pepsico demonstrate the struggle the industry has when it comes to balancing taste preferences with health concerns. Pepsico removed aspartame from sodas in 2015, bringing it back a year later, only to remove it again in 2020.
Listing aspartame as a possible carcinogen is intended to motivate more research, said the sources close to the IARC, which will help agencies, consumers and manufacturers draw firmer conclusions.
Coca-Cola has been approached by the Standard for a comment.
