Aspartame is a sugar-free, low-energy sweetener, 200 times sweeter than sugar. It has been used in a variety of foods and drinks, usually in place of sugar, for more than 25 years. Having a sweet taste, whilst being low in energy, aspartame has been sort after by those who wish to decrease their sugar intake for reasons such as weight control or diabetes.

What is it made of?

Aspartame is made up of the amino acids phenylalanine and aspartic acid as well as a small amount of methanol. Aspartame is broken down in the body into these three compounds, all of which occur naturally in many common foods. The body uses phenylalanine, aspartic acid and methanol in exactly the same way whether it comes from aspartame or another food. Aspartame does not enter the bloodstream or accumulate in the body.

Who should avoid it?

As aspartame contains phenylalanine, it should not be consumed by those with phenylketonuria (PKU). PKU is a rare genetic disease diagnosed soon after birth, where a person cannot process phenylalanine properly and so it builds up in their bloodstream. PKU is managed by avoiding foods high in phenylalanine.

Foods that may contain aspartame include diet soft drinks, diet yoghurt, chewing gums, low-calorie sweeteners and calorie-reduced foods. When used, aspartame will appear in the list of ingredients as aspartame or as E951.


Controversy: aspartame and cancer

Aspartame has attracted a high level of interest over the last few years, due to concerns raised over its safety. One concern regards the production of methanol when aspartame is broken down in the body. The amount of methanol produced, however, is small and often less than from foods in which methanol occurs naturally, e.g. bananas, citrus fruit and some vegetables. An animal study suggested that very high doses of aspartame increased the risk of certain cancers in rats (Soffritti et al., 2006). However, critics of the study pointed out that the amount fed to the rats was equivalent to 8 to 2,083 cans of diet soda (Abegaz., 2007). Large studies conducted in humans have found no links between aspartame intake and cancer (Mishra et al., 2015)

An ‘acceptable daily intake (ADI)’ is set for all food additives in New Zealand. A woman would have to consume 14-15 cans of a sugar-free drink containing aspartame every day before reaching aspartame’s ADI; men even more. A 2003 survey by Food Standards Australia New Zealand (FSANZ) showed, on average, New Zealanders reach only 4% of the ADI, while those taking in higher amounts of aspartame, reached only 13% of the ADI.

Aspartame is one of the most extensively tested food ingredients. It has been deemed safe by independent regulatory authorities in more than 100 countries including the European Food Safety Authority, Ministry for Primary Industries (MPI) and the U.S. Food and Drug Administration (FDA). Food Standards Australia New Zealand (FSANZ) has further information available here, which outlines the most recent research on the safety of aspartame.


Using aspartame has been proven to be safe but like sugar, and most other sweeteners it is best to have them in limited amounts. The majority of your diet should be based on whole and minimally processed food and water as your main drink.



Abegaz, E. G. (2007). Aspartame Not Linked to Cancer. Environmental Health Perspectives, 115(1), A16-A17.

Mishra, A., Ahmed, K., Froghi, S., & Dasgupta, P. (2015). Systematic review of the relationship between artificial sweetener consumption and cancer in humans: analysis of 599,741 participants. International Journal of Clinical Practice, 69(12), 1418-1426.

Soffritti, M., Belpoggi, F., Esposti, D. D., Lambertini, L., Tibaldi, E., & Rigano, A. (2006). First Experimental Demonstration of the Multipotential Carcinogenic Effects of Aspartame Administered in the Feed to Sprague-Dawley Rats. Environmental Health Perspectives, 114(3), 379-385.

Lastest Review: 20/06/22

Last modified: July 14, 2022