WHO: Aspartame safe to consume despite weak cancer link

The common artificial sweetener aspartame is safe to consume despite some weak evidence linking it to a common type of liver cancer, according to two separate reports previewed by World Health Organization (WHO)-affiliated researchers on Friday.

Aspartame is commonly used to replace sugar in food and drink products such as diet soda or chewing gum.

Both assessments, one of which found there were no new health risk linked to aspartame and the other found a possible cancer link, are based on reviews of existing scientific literature and don’t include new research. The WHO only presented the summaries of the reports, with the full evaluations to be published within six months, the health authority said.

While the WHO reiterated that the sweetener is safe, the organization’s head of food safety department said quantity was key.

"We’re not advising companies to withdraw products nor we are advising consumers to stop consuming altogether. We’re just advising for a bit of moderation," said Francesco Branca, the director of the WHO’s food safety department, commenting on the results.

The first report — looking at consumption — was authored by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA). It didn’t detect any new risks linked to the consumption of aspartame and reconfirmed its previous safe acceptable daily intake of aspartame of up to 40 milligrams per kilo — or around 15 cans of diet soda for an adult man.

The second aspartame report — looking at whether the sweetener could cause cancer — was conducted by the WHO’s International Agency for Research on Cancer (IARC). Here, the agency did find a possible risk based on three studies that observed increased rates of hepatocellular carcinoma — a type of liver cancer — in drinkers of artificially sweetened beverages.

However, the report stated it was unable to exclude that sampling bias or chance could have produced the result. It also found that there was some limited evidence in animal studies, but that was also somewhat ambiguous.

As a result, the IARC gave the sweetener a classification of Group 2B, the second lowest risk level, meaning it is means it is "possibly carcinogenic to humans" based on inconclusive evidence. This puts aspartame in the same category as aloe vera and pickled vegetables.

Mary Schubauer-Berigan, acting head of IARC’s monographs program, said more research into aspertame was needed.

Paul Pharoah, a professor of cancer epidemiology at the Cedars-Sinai Medical Center in Los Angeles said that the public shouldn’t be worried by the results: "The evidence that aspartame causes primary liver cancer, or any other cancer in humans is very weak."

Some scientists have linked artificial sweeteners to other health risks, most notably diabetes. A recently published evidence review from the WHO recommends against the use of artificial sweeteners to lose weight, noting there is not any evidence for this effect.