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Aspartame, updated assessment of risks on health, cancer and pregnancy

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Context - Aspartame is one of the most widely used artificial sweetener, is it safe?

This is a faithful summary of the leading report produced in 2013 by the European Food Safety Authority (EFSA): "Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive " 

  • Source document:EFSA (2013)
  • Summary & Details: GreenFacts
Latest update: 28 March 2017


In 2011 and 2013, EFSA, the European Food Safety Authority, updated its Opinion on the basis of the most recent studies on aspartame including the assessment of all unpublished studies.

What is aspartame?

Aspartame (E 951) is a dipeptide of L-phenylalanine methyl ester and L-aspartic acid, two amino acids which are natural components of proteins. It is used as an artificial sweetener authorised as a food additive in the EU. Once ingested, aspartame is rapidly and completely hydrolysed in the gastrointestinal tract to its degradation products, which are mainly phenylalanine and aspartic acid, but also diketopiperazine (DKP) and methanol.

What is phenylketonuria?

Some humans show a slightly reduced capacity to eliminate phenylalanine compared to normal individuals but some (the so-called phenylketonuria (PKU) patients) have a markedly reduced capacity for phenylalanine elimination. Phenylketonuric mothers with poorly controlled phenylalanine intake in their diet during pregnancy may give birth to babies with congenital heart diseases, microcephaly and impaired neurological function. If the phenylalanine intake via the diet is not strictly controlled phenylcetonuric babies show severe impairment in development and cognition.

This is why it is recommended to persons suffering from phenylketonuria to not consume aspartame and to limit as much as possible their exposure to phenylalanine, which is naturally present in the regular diet. Most of the food items in which aspartame is authorised are subject to limitations.

Were the EFSA conclusions modified after the risk reevaluation of aspartame?

The EFSA confirmed that aspartame consumption was not a safety concern at the current exposure estimates, which are below the Acceptable Daily Intake (ADI) recommended in 2006 of 40 mg/kg body weight/day .

What about the results of the carcinogenicity studies not considered in the previous evaluation?

No new data demonstrated a genotoxic or carcinogenic potential of aspartame; in particular the results of a carcinogenicity study on aspartame conducted in mice in 2010, did not provide a sufficient basis to reconsider the previous evaluations on aspartame.

The expert committee also noted there was no epidemiological evidence for possible associations between aspartame consumption and various types of cancers in the human population.

Are there risks of developmental effects on the foetus or premature delivery linked to aspartame?

Many experimental studies were conducted on the potential toxicity of aspartame on reproduction and development. High levels of phenylalanine in the blood is known to cause problems with development, but when the phenylalanine originating from aspartame consumption is added to the phenylalanine from the diet, it was calculated that exposure is still too low to cause such effects. For the risk of premature delivery, there is no evidence from epidemiological studies to support a causal relationship, however, additional studies are required to definitively conclude about such possible association.

Available also the opinions on aspartame of the EFSA scientific committee published in 2009 and 2011:
Note : another scientific assessment of aspartame :
'Aspartame: A Safety Evaluation Based on Current Use Levels, Regulations, and Toxicological and Epidemiological Studies', Magnuson et al , Critical Reviews in Toxicology, 37:8, 629 – 727  

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