EFSA assesses new aspartame study and reconfirms its safety

Aspartame, an intense sweetener, has been authorized for use in foods and as a table-top sweetener for more than 20 years in many countries throughout the world. Extensive investigations have been carried out on aspartame and its breakdown products through experimental animal and human studies, intake studies and post-marketing surveillance. In addition to a number of safety evaluations conducted in the past, the Scientific Committee on Food (SCF) carried out a review of all original and more recent studies on aspartame in 2002[3] and reconfirmed that aspartame is safe for human consumption. However, since it was introduced onto the market, the safety of aspartame has been a controversial issue. In 2005, the European Ramazzini Foundation published new findings of a long-term study on aspartame conducted in rats. The scientists from the European Ramazzini Foundation concluded that the results of their study indicate that aspartame can cause cancer and that the current guidelines on the use and consumption of the sweetener should be re-evaluated. EFSA immediately undertook the evaluation of the new findings and requested that the European Ramazzini Foundation provide all study details necessary for the assessment. The European Commission confirmed the need to assess the study and supported the high priority given to this work.

The Panel has evaluated extensive data from the new study on aspartame provided to EFSA by the European Ramazzini Foundation. The Panel noted that this lifetime study used more animals per dose group and a larger number of doses than conventional carcinogenicity studies. It therefore represented a substantial effort and had the potential to be more sensitive to low incidence effects. However, a number of major issues with the study were identified by the Panel which made interpretation of the findings difficult. Notably, a high background incidence of chronic inflammatory disease in the lung and other organs was observed in all the animal groups including controls which did not receive aspartame, as reported by the European Ramazzini Foundation. This was considered to be a major confounding factor. In detail the Panel concluded the following:

• The slight increase in incidence of cancers known as lymphomas and leukemias in treated rats was considered to be unrelated to aspartame treatment and most likely attributed to the high background incidence of inflammatory changes in the lung. In addition, there was no dose-response relationship with respect to increasing doses of aspartame.
• The findings in the kidney, ureter and bladder, observed mainly in female rats, are not specific to aspartame and have been observed with a number of chemicals administered to rats at high dose levels. Such changes are normally the result of irritation or imbalances in calcium metabolism specific to rats and are of no relevance for humans.
• Concerning the malignant tumours of the peripheral nerves, the numbers of tumours were low with no clear dose- response relationship over a wide dose range. There is also uncertainty about the diagnosis of these tumours. The Panel indicated that this finding can only be fully evaluated by an independent peer-review of the relevant tissues.

Finally the Panel concluded that based on all the available data to date there is no reason to further review the previous scientific opinion on the safety of aspartame nor to revise the Acceptable Daily Intake (ADI) for aspartame of 40 mg/kg body weight. Commenting on the AFC Panel’s risk assessment, Dr. Herman Koëter, EFSA Acting Executive Director, said: “EFSA considers that the results of this new study on aspartame do not provide a scientific basis for reconsidering its use in foods. If any new information would become available in the future, EFSA will review these as a matter of priority.” 

The full text of the opinion is available at: http://www.efsa.europa.eu/en/scdocs/scdoc/356.htm  

For additional information, please see the related background documents (Frequently Asked Questions on aspartame) and links to previous press releases and risk assessments related to aspartame which are provided on the EFSA website at: http://www.efsa.europa.eu/en/anstopics/topic/aspartame.htm