The decisions are the result of two separate panels of WHO experts, one of which indicates whether there is any evidence that a substance poses a potential hazard, and the other of which assesses how much of a real risk the substance actually poses.
Aspartame is one of the world’s most popular sweeteners, used in products ranging from Diet Coke to Mars’ Extra chewing gum.
At a press conference before the announcement, WHO nutrition chief Francesco Branca suggested that consumers considering beverage choices should not consider either aspartame or the sweetener.
“If consumers are faced with the decision of whether to drink Coke with sweeteners or with sugar, I think a third option should be considered – drinking water instead,” Branca said.
The International Agency for Research on Cancer (IARC), based in Lyon, France, said aspartame is a “possible carcinogen” in its first declaration on the additive, announced on Friday.
This classification means that there is limited evidence that the substance can cause cancer.
It does not take into account how much a person would have to consume to be at risk, which is assessed by a separate panel, the Joint WHO-Food and Agriculture Organization (FAO) Committee on Food Additives (JECFA), based in Geneva.
After conducting its own comprehensive review, JECFA said on Friday it had no conclusive evidence of harm caused by aspartame and continued to advise people to keep aspartame consumption below 40mg/kg per day.
JECFA first established this level in 1981, and regulatory bodies around the world have similar guidelines for their populations.
Several scientists not associated with the reviews said the evidence linking aspartame to cancer is weak. The Food and Beverage Industry Association said the rulings showed aspartame was safe and a good choice for people looking to reduce sugar in their diet.
The WHO said that current levels of consumption, for example, mean that a person weighing 60-70 kg would have to drink more than 9-14 cans of soda a day to exceed the limit, based on the average content of aspartame in drinks – about 10 times. what most people consume.
“Our results do not suggest that occasional consumption may pose a risk to most consumers,” Branca said.
Reuters first reported in June that the IARC would list aspartame in Group 2B as a “possible carcinogen,” along with aloe vera extract and traditional Asian pickled vegetables.
The IARC panel said Friday it made its decision based on three human studies in the United States and Europe that suggested a link between hepatocellular carcinoma, a form of liver cancer, and the consumption of sweeteners, the first of which was published in 2016.
It said limited evidence from earlier animal studies was also a factor, although those studies are controversial. There is also some limited evidence that aspartame has some chemical properties that are linked to cancer, the IARC said.
“In our view, it’s more of a challenge for the research community to try to better clarify and understand the carcinogenic hazard that may or may not pose aspartame consumption,” said Mary Schubauer-Berigan, acting head of the IARC Monographs Program.
Unrelated to the WHO review, the researchers said the evidence that aspartame causes cancer is weak.
“Group 2B is a very conservative classification in that almost any evidence of carcinogenicity, however flawed, will put a chemical in that category or higher,” said Paul Pharaoh, a professor of cancer epidemiology at Cedars Sinai Medical Center in Los Angeles. He said JECFA concluded there was no “compelling evidence” of harm.
“The general public should not be concerned about the cancer risk associated with a chemical classified by the IARC as Group 2B,” Pharaoh said.
Nigel Brockton, vice president for research at the American Institute for Cancer Research, said he expects aspartame research to take the form of large observational studies that account for any aspartame intake.
Some doctors have expressed concern that the new “possible carcinogen” classification could prompt diet soda drinkers to switch to high-calorie, sugar-laden drinks.
Therese Bever, medical director of the Cancer Prevention Center at the University of Texas MD Anderson Cancer Center, in Houston, said that “the potential for weight gain and obesity is a much bigger problem and a bigger risk factor than aspartame could ever be.”
The WHO conclusion “reaffirms that aspartame is safe,” said Kate Loatman, executive director of the Washington-based International Council of Beverage Associations.
“Aspartame, like all low-calorie/no-calorie sweeteners, when used as part of a balanced diet, provides consumers with the opportunity to reduce their sugar intake, which is a critical public health objective,” said Frances Hunt-Wood, secretary general of the Brussels-based International Association. Sweeteners Association.