WHO cancer arm deems aspartame ‘possible carcinogen’; consumption limits unchanged

The sweetener aspartame is a “possible carcinogen” but it remains safe to consume at already-agreed levels, two groups linked to the World Health Organization (WHO) declared on Friday.

The rulings are the outcome of two separate WHO expert panels, one of which flags whether there is any evidence that a substance is a potential hazard, and the other which assesses how much of a real-life risk that substance actually poses.

Aspartame is one of the world’s most popular sweeteners, used in products from Coca-Cola diet sodas to Mars’ Extra chewing gum.

In a press conference ahead of the announcement, the WHO’s head of nutrition, Francesco Branca, suggested consumers weighing beverage choices consider neither aspartame nor sweetener.

“If consumers are faced with the decision of whether to take cola with sweeteners or one with sugar, I think there should be a third option considered – which is to drink water instead,” Branca said.

In its first declaration on the additive, announced early on Friday, the International Agency for Research on Cancer (IARC), based in Lyon, France, said aspartame was a “possible carcinogen”.

That classification means there is limited evidence a substance can cause cancer.

It does not take into account how much a person would need to consume to be at risk, which is considered by a separate panel, the WHO and Food and Agriculture Organization (FAO) Joint Committee on Food Additives (JECFA), based in Geneva.

After undertaking its own comprehensive review, JECFA said on Friday that it did not have convincing evidence of harm caused by aspartame, and continued to recommend that people keep their consumption levels of aspartame below 40mg/kg a day.

JECFA first set this level in 1981, and regulators worldwide have similar guidance for their populations.

Several scientists not associated with the reviews said the evidence linking aspartame to cancer is weak. Food and beverage industry associations said the decisions showed aspartame was safe and a good option for people wanting to reduce sugar in their diets.

The WHO said the existing consumption levels meant, for example, that a person weighing 60-70kg would have to drink more than 9-14 cans of soda daily to breach the limit, based on the average aspartame content in the beverages – around 10 times what most people consume.

“Our results do not indicate that occasional consumption could pose a risk to most consumers,” said Branca.