A widely used artificial sweetener deemed a “possible” cause of cancer is safe in limited quantities, such as consuming fewer than nine to 14 cans of soft drink a day, experts have said.
The sugar substitute aspartame, used in thousands of products including diet fizzy drinks, ice-cream and chewing gum, was classified as “possibly carcinogenic to humans” in a report released on Thursday by the World Health Organization’s International Agency for Research on Cancer (IARC).
The IARC has two more serious categories: “probably carcinogenic to humans” and “carcinogenic to humans”.
But the Food and Agricultural Organisation’s Joint Expert Committee on Food Additives, which carried out a complementary study, retained its advice that it is safe for a person to consume 0-40mg for every kg of body weight each day.
The WHO said a person weighing 70kg would need to drink more than between nine and 14 cans of diet soft drink a day to exceed the daily guideline.
Dr Francesco Branca, director of the WHO’s department of nutrition and food safety, said: “The assessments of aspartame have indicated that, while safety is not a major concern at the doses which are commonly used, potential effects have been described that need to be investigated by more and better studies.
“We’re not advising consumers to stop consuming [aspartame] altogether. We’re just advising a bit of moderation.”
Both studies cited “limited evidence” and called for more research into the issue. The WHO said it and the IARC would continue to monitor evidence and encourage independent research groups.
Used as an artificial sweetener since the 1980s, aspartame gives a taste 200 times sweeter than sugar for few calories. The chemical is also found in products including some yoghurts, breakfast cereals, toothpastes and medications such as cough drops and chewable vitamins.
Harriet Burt, a senior policy and international projects officer for World Action on Salt, Sugar & Health based at Queen Mary University of London, said the report emphasised the need for a new approach by food and drink manufacturers.
“This new report from the WHO shows that companies need to reduce the overall sweetness of their products rather than relying so much on sweeteners,” she said. “When done correctly, reformulation can gradually remove excess sugars, salt and saturated fat from foods to improve their overall healthiness without the need for replacement ingredients such as non-sugar sweeteners.”
She continued: “Worryingly, sugar consumption in the UK is still double the recommended levels due to a food system that promotes overconsumption of excessively sweet products high in salt and saturated fat. This is why reducing sugar consumption should remain a priority.
“Based on recent WHO reports, it is clear that the UK government urgently needs a comprehensive strategy to reduce not just sugar but overall product sweetness, including the use of non-sugar sweeteners like aspartame.”
Dr Mary Schubauer-Berigan, of the International Agency for Research on Cancer, told the BBC the “evidence was not of sufficiently high quality or convincing enough” and that “this is really more a call to the research community” to study the sweetener more.
