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Aspartame – what it is and why it’s used in our food

A safe alternative to sugar
How we know aspartame is safe
How aspartame is regulated in New Zealand
How you can avoid aspartame
More information
What other food safety authorities say about aspartame
NZFSA’s responses to media reports
Related links

Despite decades of scientific research attesting to the safety of aspartame, negative allegations about it regularly appear in the media and on the internet. We use sound science and evidence-based information to address unfounded concerns about substances in our food supply.

This page aims to dispel the claims made about aspartame. It explains what aspartame is, what it’s made of and how we know it’s safe. It also provides links to food authorities around the world, so you can find out what they say about aspartame.

A safe alternative to sugar

Aspartame is an intense sweetener – about 200 times sweeter than sugar. It’s used to replace conventional sugar in low calorie or sugar free foods, including carbonated soft drinks, yoghurt and confectionary. Aspartame has been authorised for many years in many countries following thorough safety assessments. It offers a safe, low calorie option for anyone who wants or needs to limit their sugar intake; and unlike sugar, aspartame does not contribute to tooth decay.

It contains two amino acids, aspartic acid and phenylalanine as a methyl ester. Amino acids are the building blocks of protein. Aspartic acid and phenylalanine are found in foods that contain protein, such as meats, grains and dairy products. Methyl esters are also found in fruits and vegetables. Aspartame is digested to aspartic acid, phenylalanine and methanol. These compounds occur naturally in foods, are absorbed, metabolised and excreted by normal body processes.

Aspartame is listed in the ingredient list on a food label either by its name or by its number (951). Products containing aspartame also list phenylalanine on their ingredients label.

The exception for people who suffer from Phenylketonuria (PKU)

Some people have the rare inherited disease Phenylketonuria (PKU) and cannot safely consume aspartame because they are unable to metabolise the amino acid phenylalanine, which may accumulate to potentially harmful levels.

People with PKU are normally diagnosed shortly after birth by a routine blood test and need to follow a very strict diet to limit their intake of phenylalanine. All food products containing aspartame must state they contain phenylalanine so people with PKU can safely avoid harm.

How we know aspartame is safe

We accept that most substances can cause unexpected effects in some individuals and we would not dispute that for some sensitive people – aspartame could potentially cause side effects. As well, too much of any substance – even water – can create problems for some.

However, there is no scientific evidence of any significant adverse affects from aspartame when it is consumed at sensible levels. Even with high doses, the metabolites of this sweetener do not accumulate in toxic amounts. If you need or wish to limit your intake of sugars, and/or reduce your energy intake, there are clear benefits in consuming foods sweetened with aspartame or other artificial sweeteners. Aspartame is well tolerated by healthy adults and children.

There have been a number of misleading or unsubstantiated claims suggesting adverse human health effects from aspartame. These include possible toxicity from methanol; elevated blood levels of aspartic acid and phenylalanine; affects on nerves and the brain and a claimed link with epilepsy and brain tumours.

The Italian-based Ramazzini Foundation of Oncology and Environmental Sciences has released two reports since 2005, each claiming to have found a significant increase in lymphomas and leukaemias in rats exposed to a diet containing aspartame.

Food safety authorities worldwide have evaluated these and other studies. This group has not found any sound, scientific evidence of harm that might lead us to review the Acceptable Daily Intake (ADI) of aspartame.

Food safety authorities who independently came to the same conclusion include:

• Food Standards Australia New Zealand (FSANZ)

• United Kingdom Food Standards Authority (UKFSA)

• Canadian Food Inspection Agency (CFIA)

• United States Food and Drug Administration (USFDA).

The Acceptable Daily Intake (ADI) of aspartame is set at 40 milligrams per kilogram of body weight (40 mg/kg-bw) – one of the highest intakes allowed among food additives. This ADI also takes into account the body’s ability to process the relatively small amounts of methanol resulting from digesting aspartame.

An Acceptable Daily Intake is the amount of an additive that can be taken-in daily over a lifetime without damaging a person’s health. It is expressed in relation to bodyweight (bw) to allow for different body size, such as for children of different ages.

How aspartame is regulated in New Zealand

The Food Standards Code sets out which foods can have aspartame added to them. These permissions are the result of a comprehensive assessment and review of all food additives, undertaken by Food Standards Australia New Zealand (FSANZ).

FSANZ safety assessments are based on evaluations and acceptable daily intakes by the Joint World Health Organization and Food and Agriculture Organisation’s Expert Committee on Food Additives (JECFA).

Frequently asked questions about the Food Standards Code [FSANZ]

How you can avoid aspartame

Even though aspartame is recognised as being safe, you may wish to avoid foods that contain it. Food labelling enables you to make informed choices about the foods you eat. The law requires manufacturers to list food additives and other ingredients, including sweeteners such as aspartame.

Aspartame is listed in the ingredient list on a food label either by its name or by its number (951). Products containing aspartame also list phenylalanine on their ingredients label.