What is aspartame?
Aspartame is a low-calorie sweetener used for decades in a wide variety of food and beverage products across the world, including soft drinks, yoghurts and chewing gum. Aspartame is also frequently used as a tabletop sweetener to replace sugar.
Foods and beverages made with aspartame are extremely common and aspartame is considered a safe and effective alternative to sugar by public health authorities around the world.
What are the safe levels of consumption for aspartame?
Aspartame, like any other low-calorie sweetener authorised for use, is safe to be consumed according to current approved levels.
In Europe, the European Food Safety Authority (EFSA) sets the ‘Acceptable Daily Intake’ (ADI), which is the amount of a food additive that can be consumed daily in the diet, over a lifetime, without risk to health.
The ADI is expressed on a body weight basis –milligrams (mg) per kilogram (kg) of body weight (bw) per day.
The ADI has a huge safety margin – it is usually 100 times lower than the amount known NOT to have any adverse effects. As an example, for an adult, the equivalent of consuming the upper level of the ADI on any given day for aspartame, through consuming soft drinks alone (and if sweetened at the EU maximum permitted level), would equate approximately to 4 litres of soft drink.
Aspartame is safe
Aspartame has a long track record of scientific studies confirming it to be a safe.
|More than 100 scientific studies conducted by more than 200 independent researchers over 40 years confirm aspartame is safe.
Food safety agencies from over 90 countries, including EFSA, the U.S. FDA, Health Canada, UK Food Standards Agency, Food Safety Commission of Japan, and Food Standards Australia and New Zealand say aspartame is safe. Nothing has changed to undermine that.
EFSA has repeatedly reconfirmed the safety of aspartame. Its latest scientific opinion, released in 2013, concluded that aspartame is safe for the general population, including for infants, children and pregnant women. In 2018, the U.S. FDA also re-affirmed the safety of aspartame and, in 2023, it reconfirmed that aspartame is safe.
WHO re-affirms the safety of aspartame
On 14 July 2023, two bodies within the World Health Organization (WHO) released the conclusions of their reviews of aspartame.
One of the bodies is the WHO/FAO (Food and Agriculture Organization) Joint Expert Committee on Food Additives (JECFA), the leading global expert on the safety of food additives. WHO/JECFA conducted a rigorous and comprehensive safety review of all available evidence, examining the impact of aspartame on human health based on level of exposure.
On 14 July 2023, JECFA has re-affirmed the safety of aspartame, re-confirming the ‘Acceptable Daily Intake’ (ADI) of 0-40 mg per kg body weight per day (see JECFA summary findings). This is an estimate of the amount of aspartame that can be safely consumed every day over a lifetime. The JECFA ADI is exactly the same as the EFSA ADI.
The second body is the International Agency for Research on Cancer (IARC). IARC, unlike JECFA, is NOT a food safety body. IARC conducts a far more narrow hazard analysis, looking only at the potential for an ingredient to cause cancer – not the actual risk based on level of exposure.
- IARC classified aspartame in its group 2B – “possibly carcinogenic to humans based on limited evidence in humans and less than sufficient evidence in experimental animals.” (see summary evaluation of the IARC hazard identification published in The Lancet Oncology). IARC relied on studies which have consistently been considered as unreliable by food safety authorities. IARC has previously classified pickled vegetables and working the night shift as cancer hazards.
Global reactions from food safety authorities and regulators to the publication of the IARC and JECFA assessments
Austrian Agency for Health and Food Safety (AGES)
WHO/JECFA findings that “there is no convincing evidence that aspartame has adverse effects” […] are in line with the conclusions of [the European Food Safety Authority] 2013 assessment on aspartame.” Moreover, “daily intake of aspartame in [Austrian] children, adolescents, adults and pregnant women was between max. 0.16- 1.38 mg/kg bw/day. This means that their intake is only about 3.5% of the Acceptable Daily Intake.”
Belgian Federal Public Service (FPS) Health, Food Chain Safety and Environment
“There is … no reason for JECFA to change the acceptable daily intake of 40 mg of aspartame per kilogram of body weight per day. The consumption of aspartame within this limit is… still considered safe.”
Croatian Agency for Agriculture and Food (HAPIH)
“Aspartame has been approved for human consumption for many years after thorough safety assessments, and the European Food Safety Authority (EFSA), which is in charge of assessing the safety of food additives in the EU, conducted the last aspartame risk assessment in 2013. New findings from IARC and JECFA confirmed the conclusions of EFSA’s assessment of aspartame.”
Vlastimil Valk, Minister of Health of Czechia
“It’s not even that there is a huge risk, but it’s that even a minimal risk doesn’t occur, that’s why we’re always much more careful and strict. In practical terms, it will mean absolutely nothing for the Czech citizen.”
Mari Reinik, Deputy Director of the National Centre for Laboratory Research and Risk Assessment
“Since the acceptable dose has not been changed based on current research, it does not give a direct signal to change people’s behavior.”
Hellenic Food Authority (EFET)
“It is emphasized that IARC does not have the authority to make health-related recommendations. Therefore, IARC does not recommend legislation or other public health interventions, which are the responsibility of other international organizations and national bodies. JEFCA concluded that there is no convincing evidence from animal or human studies that aspartame has adverse health effects after its consumption.
Regarding epidemiological studies, the JEFCA committee concluded that a consistent (clear) association between aspartame consumption and any specific type of cancer has not been demonstrated.
Evaluating all of the above, JEFCA does not change the value of the Acceptable Daily Intake for aspartame, which remains 40 mg/kg of body weight per day.
For aspartame, this value, based on today’s opinion of JEFCA, does not change and remains the same as that of the European Food Safety Authority (EFSA) which is set as 40 mg/kg of body weight per day.’’
National Food Chain Safety Office (NEBIH)
Comments from György Pleva, director of food and feed safety at Nébih
“This means that the carcinogenic effect of aspartame itself has not been directly confirmed, but it may happen that under certain circumstances, above a certain amount, the possibility of cancer increases.” For this reason, it was judged that the current average daily intake value does not need to be reduced, since the results of the research were not considered to be well-founded, and further investigation is needed to assess a more serious tightening. This means that, as in the world, in the European Union as well, 40 mg per kilogram of body weight is the permissible value in the future.”
Food Safety Authority of Ireland
“JECFA concluded that there was no convincing evidence from experimental animal or human data that aspartame has adverse effects after ingestion. […] The findings of JECFA are in line with the conclusions of the European Food Safety Authority’s (EFSA) latest assessment on aspartame in 2013. Aspartame has also been evaluated by numerous scientific committees internationally over many years and has been found to be safe. It is authorised for human consumption in many countries following thorough safety assessments.”
Portuguese Food Safety Authority (ASAE)
“ASAE’s Scientific Council considers that there is no new data to change the EFSA recommendations regarding the use of aspartame as a sweetener. The admissible daily dose of 40 mg/kg bw/d does not pose an increased health risk. […] The epidemiological studies carried out to date do not show a direct relationship between the consumption of aspartame and the incidence of cancer or other disease caused by aspartame.”
The Swedish Food Agency
“… there are no known risks of consuming aspartame. The Swedish Food Agency therefore has no special recommendations regarding the consumption of aspartame.
JECFA considers the evidence for a link between the consumption of aspartame and human cancer to be inconclusive. JECFA’s conclusion is that the data evaluated do not provide sufficient reason to change the previously established maximum daily intake for consumers (ADI value).’’
What scientists say
“In short, the evidence that aspartame causes primary liver cancer or any other cancer in humans is very weak… Group 2b is a very conservative classification in that almost any evidence of carcinogenicity, however flawed, will put a chemical in that category or above.”
Professor of Cancer Epidemiology, Cedars-Sinai Medical Center
“If the ADI is maintained by JECFA and other agencies and food safety authorities worldwide due to lack of scientific evidence, alarmism should not be generated. I don’t imagine that an institution like the WHO says that a drug poses a risk and the medicines agencies or authorities say otherwise, who are the ones that really evaluate the safety and efficacy of medicines.’’
Rafael Urrialde de Andrés
Professor, Biological Sciences at Complutense University of Madrid and Nutrition at San Pablo University,
Board Member of the Spanish Nutrition Society
“Classification alone is, at most, useless and in several cases—like in this case—is dangerous. It’s the dose that matters. Almost anything can be toxic if you have enough of it—even water.‘’
Professor at the department of cardiothoracic and cardiovascular sciences and public health at the University of Padua, Italy
“These IARC reports are getting a bit farcical. In spite of the IARC’s conclusion that aspartame was ‘possibly carcinogenic to humans’, which got lots of media attention, another expert committee (JECFA), which actually investigates the magnitude of any risk, found ‘no convincing evidence from experimental animal or human data that aspartame has adverse effects’. “As they have said for 40 years, average people are safe to drink up to 14 cans of diet drink a day, which is about an old gallon — about half a large bucketful. And even this ‘acceptable daily intake’ has a large built-in safety factor.”
Sir David Spiegelhalter
Emeritus Professor of Statistics, the University of Cambridge
‘’The [WHO committee’s] decision puts aspartame in the same category as things like aloe vera and bracken ferns. There is no convincing evidence that it causes cancer in humans and people shouldn’t be worried about getting cancer from aspartame in food and drink. Your overall diet is more important than individual foods or ingredients for reducing cancer risk. So, aim to eat a healthy, balanced diet, with more fruit, veg and wholegrains, and cut back on red and processed meats and foods high in fat, sugar and salt.”
Dr. Claire Knight
Senior Health Information Manager, Cancer Research UK
“Importantly, the same evidence that IARC considered and their report have been examined by JECFA, the WHO/FAO committee responsible for estimating whether there are any risks or likelihood of cancer developing associated with aspartame consumption. The committee saw no new reasons to change its longstanding recommendation of an acceptable daily intake 0-40 mg per kg of bodyweight without appreciable health risk.”
Prof Andy Smith
MRC Toxicology Unit, University of Cambridge
“Aspartame has not previously been classified by IARC, so its classification cannot yet have changed. It is in group 2B, not group 3, but the issue of the lack of good enough evidence does seem to apply to aspartame too.”
“But for now IARC have put aspartame in group 2, so they are saying it could possibly cause cancer under some circumstances, but that this is far from certain. So it remains perfectly possible that it cannot cause human cancers at all.”
“JECFA say that high estimates of actual consumption were 20 mg/kg bodyweight for children and 12 mg/kg of bodyweight for adults, which are well below the 40mg/kg ADI.”
Prof Kevin McConway
Emeritus Professor of Applied Statistics, Open University
“The Joint FAO/WHO Expert Committee on Food Additives committee has not changed its safety rating on Aspartame which they set at 40mg/kg body weight which for a 70 kg adult would mean drinking roughly 14 cans of Diet Coke a day, over a long period. This is consistent will all the major food safety agencies around the world who regularly conduct their own assessments and all classify aspartame as safe at the levels it is used at.”
“We are all exposed to carcinogens every day. Even things that the IARC classifies as class one carcinogens, such as UV light and alcohol, do not cause cancer just because you are exposed to them once. For example, if you get too much sun on the beach in summer you might get sunburn but you’ll recover. If you continually sunbathe with no sun protection then your risk of skin cancer goes up.”
Prof Oliver Jones
Professor of Chemistry, RMIT University
“It is somewhat difficult to judge this report as, at this stage all that IARC is publishing only a summary with a brief description of the interpretation of the available evidence by the expert working group, but, the full report with details of all the evidence considered will be published later. In short there is weak epidemiological evidence that aspartame is associated with an increased risk of primary liver cancer (that is cancer that arises in the liver rather than a cancer that started elsewhere and spread to the liver, or secondary liver cancer). This evidence comes from three studies that have reported an association but there is not much evidence to suggest that the association is ‘causal’ (association/correlation does not necessarily mean causation). In addition there was limited evidence that aspartame is carcinogenic in experimental animals, but this evidence was thought to have serious flaws. Finally, aspartame has some chemical properties that might be cancer associated.”
“In short the evidence that aspartame causes primary liver cancer, or any other cancer in humans is very weak. This is why it is classified as Group2B. Other examples of classified as Group2B are extract of aloe vera, diesel oil, caffeic acid found in tea and coffee. Group 2B is a very conservative classification in that almost any evidence of carcinogenicity, however flawed will put a chemical in that category or above.”
“This is reflected in the view of the Joint FAO/WHO Expert Committee on Food Additives who concluded that there was no convincing evidence from experimental animal or human data that aspartame has adverse effects after ingestion. They noted that aspartame is rapidly metabolised into chemicals found in many common foods. Thus the JECFA had no reason to alter their current recommendation on an acceptable daily intake of aspartame.”
“The general public should not be worried about the risk of cancer associated with a chemical classed as Group 2B by IARC.”
Prof Paul Pharoah
Professor of Cancer Epidemiology, Cedars-Sinai Medical Center, Los Angeles
“The conclusions of IARC and JECFA on aspartame reflect the respective approaches taken by the two committees. IARC has classified aspartame as 2b, which reflects a lack of confidence that the data from experimental animals or from humans is sufficiently convincing to reach a clear conclusion that aspartame is carcinogenic. But IARC did conclude that any carcinogenicity was most likely through an indirect effect and not through direct interaction with DNA (genotoxicity). JECFA reviewed all of the toxicological effects of aspartame including carcinogenicity and genotoxicity. The weight of evidence did not support any carcinogenic effect and JECFA found no basis to change its previously established acceptable daily intake. Hence, exposure at current levels would not be anticipated to have any detrimental effects.”
Prof Alan Boobis
Emeritus Professor of Toxicology, Imperial College London
“The new data in the IARC report suggests a possible link between liver cancer and aspartame in some observational studies. There has been a marked increase in liver cancer related to obesity in several Western countries, notably in the USA, that is associated with non-alcoholic fatty liver disease. Type 2 diabetes and obesity are major cause of fatty liver disease. Sugar intake has been previously linked to fatty liver disease as it encourages the synthesis of fat in the liver. There is no evidence that aspartame increases fat accumulation in the liver. People with diabetes or who are obese are more likely to use artificial sweeteners compared with those who are not obese. Consequently, this association while consistent may not be causal.”
“IARC noted the evidence is limited because they cannot rule out confounding factors and because the data from animal studies is inconsistent, aspartame was classified 2b – a possible cancer hazard. JECFA, however, does not believe the risks posed by aspartame are anything to be concerned about providing the amounts of aspartame consumed are below the acceptable daily intake, which are unlikely to be exceeded in practice.”
Prof Tom Sanders
Professor emeritus of Nutrition and Dietetics, King’s College London
“The publication of the IARC and JECFA opinion is very welcome as it ends the speculation about the safety of Aspartame. The two WHO agencies have done what they are supposed to do: IARC has reviewed the data and found some very limited evidence that Aspartame could cause cancer – and based on the same data JECFA has concluded that a consumption up to 40 mg per kg of body weight per day is safe and there is no need to change current recommendations.”
“It is unfortunate that leaking some information might have created unnecessary uncertainty and concern as consumers might be rightfully worried if they are told that something that is in many foods could cause cancer. The published opinion puts this into perspective and makes it very clear that there is no cause for concern when consumed at the current amounts. Scientific advisory bodies are often unable to react quickly and respond to an emerging story so it’s good they will now have both the IARC and JECFA assessments to digest and respond to.”
“This illustrates also the importance of distinguishing between hazard and risk and highlights the difficulty in communicating hazards: sunlight is a hazard as it can cause cancer, but the risk depends on the amount of sun light and whether we use protection. Likewise, even if Aspartame causes cancer at very high amounts, there is no risk when consuming it at the amounts that are permitted in foods.”
Prof Gunter Kuhnle
Professor of Nutrition and Food Science, University of Reading
- Critical role of JECFA expert risk assessment body reinforced as report on aspartame published by CODEX Alimentarius (international food safety standards)
- A critical appraisal of the WHO reviews of aspartame by the International Sweeteners Association (ISA)
- In the news: does aspartame increase our risk of cancer? by European Food Information Council (EUFIC)
- Belgian website on sweeteners – Edulcorants
- Dutch website on sweeteners – Zoetstoffen