The findings of two World Health Organization studies into the safety of artificial sweetener aspartame have revealed the ingredient is a “possible carcinogen” but can be consumed safely within previously recommended guidelines.
The International Agency for Research on Cancer (IARC) said aspartame should be added to the list of possibly carcinogenic substances. However, a separate report by the Joint Food and Agriculture Organisation and WHO Expert Committee on Food Additives (JECFA) said it had not found convincing evidence of the link between the substance and cancer.
The JECFA review said it would maintain its guidance that aspartame was safe to consume in moderation. It continued to recommend people keep consumption of aspartame below 40mg/kg a day, a level it first set in 1981.
For the average person, this would be equivalent to between nine to 14 cans of diet soda per day.
“Science is continuously expanding to assess the possible initiating or facilitating factors of cancer, in the hope of reducing these numbers and the human toll,” said Dr Francesco Branca, director of the department of nutrition and food safety at the WHO.
“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.”
The IARC classification of aspartame as a possible cancer-causing substance had leaked earlier this month, causing consternation from food and beverage makers worldwide. Aspartame is a popular ingredient used in products from chewing gum to diet soft drinks and low-calorie ice cream.
However, the IARC review did not take into account how much aspartame a person would have to consume for it to be risky. The classification places aspartame in the same category as aloe vera and caffeic acid (commonly found in tea or coffee).
The JECFA review was welcomed by food and beverage associations. The International Council of Beverages Associations (ICBA) said it represented a “definitive conclusion” that aspartame was safe for consumers.
“After rigorous review, this landmark WHO finding further strengthens confidence in the safety of aspartame and will play a vital role in informing consumers as they consider all options to reduce sugar and calories in their diets,” said ICBA executive director Kate Loatman. “JECFA’s comprehensive conclusion that aspartame is safe builds on the overwhelming weight of scientific evidence for more than four decades, as well as positive determinations by food safety authorities in more than 90 countries.”
The International Sweeteners Association’s secretary general Frances Hunt-Wood added: “ECFA has once again reaffirmed aspartame’s safety after conducting a thorough, comprehensive and scientifically rigorous review. Aspartame, like all low/no-calorie sweeteners, when used as part of a balanced diet, provides consumers with choice to reduce sugar intake, a critical public health objective.”
The US Food and Drug Administration, meanwhile, took umbrage with the IARC ruling, stating it was based on “significant shortcomings” in the studies it considered when making its ruling.
“The FDA disagrees with IARC’s conclusion that these studies support classifying aspartame as a possible carcinogen to humans,” an FDA spokesperson said. “FDA scientists reviewed the scientific information included in IARC’s review in 2021 when it was first made available and identified significant shortcomings in the studies on which IARC relied.
“We note that JECFA did not raise safety concerns for aspartame under the current levels of use and did not change the acceptable daily intake.”
Speaking after PepsiCo’s second-quarter financial results were published yesterday (13 July), chief financial officer Hugh Johnston said the company had no plans to reformulate any of its portfolio following the IARC ruling.
“We don’t have any plans to change the product portfolio relative to where we are right now with aspartame,” Johnston told Reuters.
PepsiCo removed aspartame in its US diet sodas in 2020 but the substance remains present in “a few products” in the Gatorade brand owner’s roster, according to Johnson.
He added: “By far the weight of the scientific evidence suggests that aspartame is safe as an ingredient, and obviously has the benefit of being zero-calorie.”
Earlier this year, the WHO published guidance stating replacing sugar with non-sugar sweeteners like aspartame in food and beverages does not help with weight control.
It added that non-sugar sweeteners were “not essential dietary factors and have no nutritional value”.