Learn more here about aspartame. Click on the blocks below.
Why is aspartame (E 951) in the news?
The Joint FAO/WHO Expert Committee for Food Additives (JECFA) and the International Agency for Research on Cancer (IARC) have independently assessed the risks associated with aspartame and published a summary of their findings today, Friday 14 July 2023.
IARC has assessed the strength of evidence that aspartame could cause cancer in humans, while JECFA has assessed the risks to the public from the use of aspartame in food. The JECFA risk assessment includes a review of the acceptable daily intake (ADI) and evaluation of the dietary exposure to aspartame from food.
Citing “limited evidence” for carcinogenicity in humans, IARC classified aspartame as ‘possibly carcinogenic to humans (IARC Group 2B)’ and JECFA concluded that there was no convincing evidence from experimental animal or human data that aspartame has adverse effects after ingestion. This led to JECFA reaffirming its previous acceptable daily intake (ADI) of 40 mg/kg body weight.
The sequence of these evaluations and the close collaboration between the IARC and the JECFA secretariats permitted a comprehensive evaluation of the health effects of aspartame consumption based on the latest available scientific evidence.
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.
Prior to their authorisation at EU level, all additives must undergo a rigorous safety assessment, and this has been no different for aspartame which is considered safe at current permitted levels of use.
 The acceptable daily intake (ADI) is an estimate of the amount of a substance in food or drinking water that can be consumed daily over a lifetime without presenting an appreciable risk to health.↵
What is aspartame?
Aspartame (E 951) is an intense, low-calorie, artificial sweetener authorised as a food additive (sweetener) in the EU and in many countries throughout the globe. It is approximately 200 times sweeter than sugar and as a result is often used as a sugar substitute or to enhance the flavour of foods (flavour enhancer).
What foods can aspartame be found in?
In the European Union (EU), aspartame is authorised for use in low energy or sugar free foodstuffs such as flavoured drinks, desserts, confectionery, dairy products, chewing gums, food supplements, energy-reduced and weight control products, and table-top sweeteners among others.
In Ireland food additives, such as aspartame, are subject to rigorous controls under the European food additives legislation.
How do you know if your food contains aspartame (E 951)?
In the EU, aspartame must be listed on the food label. The food label must identify both the function of the additive in the finished food (e.g., sweetener or flavour enhancer in the case of aspartame) together with the specific name or E number of the additive (e.g., “sweetener: aspartame” or “sweetener: E 951”).
It is also a requirement of EU legislation that food containing aspartame indicate through labelling that they contain a source of phenylalanine. This advisory message is in place for individuals in the population who have difficulty breaking down phenylalanine, an essential amino acid that is formed after eating aspartame.
Evaluations of aspartame
Aspartame and its breakdown products have been the subject of extensive investigation for more than 40 years including experimental animal studies, clinical research, intake and epidemiological studies and post-marketing surveillance.
Aspartame has been previously evaluated by the JECFA (latest full evaluation in 1981), the EU Scientific Committee for Food (SCF) (latest in 2002) and the European Food Safety Authority (EFSA) (latest 2013) among others. Both JECFA and the SCF had established an acceptable daily intake (ADI) of 40 mg/kg body weight (bw)/day for aspartame.
Irish exposure assessments show that the exposure of all population groups to aspartame from food and beverages is below the ADI of 40 mg/kg bw/day.
EFSA is also updating its dietary exposure assessment of aspartame, and, at present, there is no indication that the ADI of 40 mg/kg bw per day is exceeded in any of the age groups of the EU population. This evaluation includes Irish food consumption data.
European Food Safety Authority (EFSA)
In its opinion in 2013, EFSA concluded that aspartame and its breakdown products (phenylalanine, methanol, and aspartic acid) are safe for human consumption at current levels of exposure.
In 2013, EFSA also concluded that the current ADI of 40 mg/kg body weight for aspartame is protective for the general population and that exposure of consumers to this sweetener is below the ADI. The latest findings of JECFA are in line with this conclusion.
EFSA is currently re-evaluating the safety of two related food additives, the salt of aspartame-acesulfame (E 962) and neotame (E 961). In its re-evaluation of E 962, EFSA will consider all new data on aspartame since they last evaluated it in 2013 and this will include the work that IARC and JECFA have published today (14 July 2023). EFSA will also update its dietary exposure assessment of aspartame.
 The salt of aspartame-acesulfame (E 962) is a mixture of the two sweeteners aspartame (E 951) and acesulfame K (E 950), while neotame (E 961) is a chemically related substance manufactured from aspartame. ↵.
What is the International Agency for Research on Cancer and the Joint FAO/WHO Expert Committee on Food Additives and what roles do they play?
The International Agency for Research on Cancer (IARC) was established in 1965 and has a unique dual position as an independent international cancer research institute, and as the specialised cancer research agency of the World Health Organization (WHO) within the United Nations system.
IARC focuses on cancer as an outcome and undertakes hazard identification, which is the first fundamental step to understanding carcinogenicity. Hazard identification aims to identify the specific properties of the agent and its potential to cause harm, i.e., the potential for an agent to cause cancer, looking at both dietary and non-dietary exposures.
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) is an international scientific expert committee that is administered jointly by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). It has been meeting since 1956, initially to evaluate the safety of food additives. Its work now also includes the evaluation of contaminants, naturally occurring toxicants, and residues of veterinary drugs in food.
JECFA considers all possible health impacts and undertakes a risk assessment, which determines the probability that a specific type of harm, including cancer, will occur under certain conditions and levels of exposure. When evaluating the safety of any chemical substance, JECFA uses all available data and evaluations including the hazard identification from IARC Monographs. The risk assessment undertaken by JECFA is based on the identified hazard properties of an agent and anticipated exposures in specific scenarios. Thus, all dietary sources, conditions of exposure including the frequency and levels of exposure are considered. JECFA’s role is specifically to perform a risk assessment for the dietary exposure scenario.
What was the outcome of the IARC hazard assessment on aspartame?
Citing “limited evidence” for carcinogenicity in humans, IARC classified aspartame as “possibly carcinogenic to humans (IARC Group 2B)”. A carcinogen is a substance that has been associated with cancer in humans. IARC’s conclusion was based on limited evidence (three epidemiological studies in humans) showing a positive association between the consumption of sweetened beverages and liver cancer. However, chance, bias or confounding by socioeconomic or lifestyle factors could not be ruled out as an explanation for the positive findings. There was also limited evidence for cancer in experimental animals and limited mechanistic evidence that aspartame shows key characteristics of a human carcinogen.
What does the IARC classification system for carcinogens mean?
IARC classifies carcinogens into four categories as outlined in the table below. IARC has assessed aspartame as a Group 2B possible carcinogen.
Carcinogenic to humans
Probably carcinogenic to humans
Possibly carcinogenic to humans
Not classifiable as to its carcinogenicity to human
Probably not carcinogenic to humans
Category 2B generally applies when only one of the following evaluations has been made by IARC:
• Limited or not convincing evidence of carcinogenicity in humans
• Sufficient evidence of carcinogenicity in experimental animals
• Strong evidence that the agent exhibits key characteristics of carcinogens
The IARC evaluation noted limitations in all three streams of evidence (humans, experimental animals, and mechanistic evidence). The “limited” evidence of liver cancers in humans is what led to the Group 2B evaluation.
It is important to understand that this classification system indicates the weight of the evidence as to whether a substance like aspartame can cause cancer. It does not measure the likelihood that cancer will occur under certain conditions and levels of exposure.
What was the outcome of the JECFA assessment on aspartame?
JECFA concluded that there was no convincing evidence from experimental animal or human data that aspartame has adverse effects after ingestion. JECFA considered the evidence on cancer risk in animal and human studies and concluded that the evidence of an association between consumption of aspartame and cancer is humans is “not convincing”. All carcinogenicity studies evaluated were noted to have limitations. They also concluded that there was a lack of a plausible mechanism for cancer development following oral exposure to aspartame. As a result, JECFA commented that the data evaluated indicated no sufficient reason to change the previously established ADI of 40 mg/kg body weight for aspartame.
To put this into perspective, a 70 kg adult, would have to consume 9–14 cans of a diet soft drink containing 200-300 mg per day to exceed the ADI, assuming no other intake of aspartame from other foods or drinks.
Both IARC and JECFA encouraged further research on the potential association between aspartame exposure and consumer health effects.
What other factors cause cancer?
Cancer is a complex disease and can be caused by several factors including genetics, smoking and other environmental factors. However, healthy eating can play an important role in the prevention of cancer and as a result consumers should eat a healthy balanced diet in line with healthy eating guidelines. Intake of foods and drinks that are high in energy, fat, sugar and salt should be limited. Current advice for healthy living to prevent cancer includes:
• Be a healthy weight
• Be active
• Avoid alcohol
• Eat plenty of fruit and vegetables
• Choose different types of fruit and vegetables
• Choose wholegrain breads and cereals
• Avoid excess fats and oils
• Limit your intake of processed foods
What are the next steps?
The FSAI’s top priority is to ensure food is safe and consumers are protected. The FSAI will closely study the IARC and JECFA evaluations of aspartame once the full reports are published. Subsequently, the FSAI will work closely with our EU partners to ensure foods containing aspartame are appropriately considered with respect to consumer protection.
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