The current acceptable daily intake level of aspartame has been reconfirmed through a risk assessment by the WHO and FAO Joint Expert Committee on Food Additives (JECFA), while the International Agency for Research on Cancer’s (IACR) classification of “possibly carcinogenic to humans” still stands. Industry applauds the reaffirmation of aspartame’s safety but worries the conflicting evaluations may confuse consumers.  

Both evaluations noted limitations in available evidence for cancer and other health effects, calling for additional research. JECFA reaffirmed the maximum daily intake of 40 mg/kg of body weight for aspartame. 

“Aspartame is one of the most rigorously researched ingredients in the food supply, with more than 100 studies and 90 credible global scientific and regulatory food agencies, including the FDA and the European Food Safety Authority confirming its safety. This is reaffirmed with the latest WHO findings,” Robert Ranking, president of the Calorie Control Council, tells Food Ingredients First. 

“The IARC classification has no impact on the industry as IARC is not a regulatory agency or food safety authority. JECFA’s review reaffirmed the safety of aspartame, and as a result, there is no reason for any changes in current practices.”

Kate Loatman, executive director of the International Council of Beverages Association, tells us: “We remain confident in the safety of aspartame given the overwhelming weight of scientific evidence and positive safety determinations now most recently by JECFA as the world’s leading food safety experts.”

Risk assessment 
In a WHO press briefing, Dr. Francesco Branca, director of the WHO Department of Nutrition and Food Safety, states that the JECFA risk assessment determined that the science was not conclusive enough to indicate that daily consumption numbers should be lowered. 

“Occasional consumption of aspartame is most probably not going to be associated with health risk for most individuals,” he says. 

Branca explains that JECFA looked at the whole risk assessment procedure: “[Starting] from the hazard identification, considering the exposure in real life to the compound and then concluding on whether consumption of aspartame at certain levels of consumption is a risk for health, not just for cancer, but for other health outcomes, particularly non-communicable diseases outcomes.”

IARC and JECFA evaluations of aspartame were based on scientific data collected from various sources, including peer-reviewed papers, governmental reports and studies conducted for regulatory purposes. 

“Possibly carcinogenic” 
During the WHO press briefing, Dr. Mary Schubauer-Berigan, deputy branch head of the Evidence Synthesis and Classification Branch and head of the IARC Monographs program, explained that the IARC evaluated aspartame due to new evidence from “studies of cancer in experimental animals and new epidemiological studies of human cancer.”

“The evidence was strongest for a carcinogenic effect for a type of liver cancer called hepatocellular carcinoma. There were some sporadic positive findings for other cancer sites like breast, obesity-related cancers and some forms of leukemia. However, those findings were not as consistent as those for this type of liver cancer,” says Schubauer-Berigan.  

The review found positive findings in three studies – the only available ones on liver cancer – which had methodological limitations that prevented drawing a firm conclusion about the carcinogenicity of aspartame, she continues. “So instead, the conclusion was possibly carcinogenic,” she adds.  

Dr. Federica Madia, the senior toxicologist at the IARC Monographs program responsible for the monograph on aspartame, highlights that though the evidence is limited, “we identified evidence in the experimental system. So either in vivo or in vitro experiments of oxidative stress, there were certain biomarkers altered, including lipid peroxidation that could lead to damage to protein or DNA.” 

Consumer confusion? 
However, trade organizations like the International Sweeteners Association (ISA) stress that the IARC is not a food safety body. The ISA states the organization’s classification of aspartame does not consider intake levels or actual risk, making the review far less comprehensive and potentially confusing to consumers. 

ISA illustrates that aspartame’s classification puts it in the same category as kimchi and other pickled vegetables. 

“Aspartame, like all low or no-calorie sweeteners, when used as part of a balanced diet, provides consumers with a choice to reduce sugar intake, a critical public health objective,” says Frances Hunt-Wood, ISA secretary general. 

Loatman notes IARC’s leaked opinion may have needlessly confused consumers with sensational speculation but highlights that IARC has deferred to JECFA as the appropriate global authority to assess the safety of consuming aspartame. “Even IARC agrees it is not the appropriate authority to undertake risk assessment based on actual consumption and that it ‘does not make health recommendations,’” she says. 

Meanwhile, Dr. Susan Elmore, a toxicology expert who participated in the IARC aspartame review as an observer, explains that because IARC only looks at the hazard potential and not risk, “it does not paint a full picture of the safety of an ingredient, like aspartame, and as a result can cause unnecessary public confusion.” 

Elmore emphasizes that aspartame has been deemed safe at real-world exposure levels by over one hundred animal studies, and the vast majority of human epidemiology studies have provided no indication that consumption of aspartame induces cancer.  

74 packets of aspartame sweetener 
Ranking of the Calorie Control Council, representing the low- and reduced-calorie food and beverage industry, notes the JECFA ruling also provides real-life context around the safe consumption of this ingredient. 

“To reach JECFA’s conservative ADI estimates, the average 150 lb. person would need to consume about 14 12-oz cans of diet beverages or about 74 packets of aspartame-containing tabletop sweetener every day over the course of their life to raise any safety concern. Obviously, that level of consumption is not realistic, recommended, nor is it ‎aligned with the intended use of these ingredients.”  

He argues that it is dangerous to position IARC’s report alongside “true scientific and regulatory agencies like JECFA, the FDA and EFSA.” 

Kevin Keane, interim president and CEO of the American Beverage Association, adds: “The purpose and expertise of food safety agencies is to ensure safety over time. The WHO has done this again, rigorously and definitively, with aspartame.”

“With more than 40 years of science and this definitive conclusion from the WHO, consumers can move forward confidently that aspartame is a safe choice, especially for people looking to reduce sugar and calories in their diets.”

Less sweet taste 
Although Branca at the WHO says even high consumers of aspartame do not exceed the acceptable daily intake, he cautions consumers not to increase their consumption of sweeteners in general. 

“Our advice is that products containing sweeteners as well as products containing sugar should be moderated. And in children, particularly, the exposure to early exposure to the sweet taste is going to track in adulthood. I think it’s important to be accustomed to a less intensely sweet taste; this is generally beneficial for healthy diets,” he explains.

In response to this recommendation, Harriet Burt, senior policy and international projects officer for World Action on Salt, Sugar & Health, highlights: “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.” 

“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.” 

She notes that 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.”