Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter to the Editor
  • Published:

Aspartame effects on the brain

European Journal of Clinical Nutrition volume 63, pages 698–699 (2009)Cite this article

The following comments relate to the review by Humphries et al. (2007). The premise of the review, that the high-intensity sweetener aspartame is neurotoxic, ignores a very large scientific literature to the contrary, recently comprehensively summarized (Butchko et al., 2002; Magnuson et al., 2007).

The key point about aspartame is that very little is consumed. Because it is 180 times sweeter than sugar, relatively little shows up in products. For example, a 355 ml can of diet soda contains 180 mg of aspartame, which for a 70 kg human is a 2.5 mg kg−1 dose (1.25 mg kg−1 phenylalanine). After its introduction, its use was monitored for years, revealing that average daily dosing is barely 5 mg kg−1 day−1 (2.5 mg kg−1 day−1 phenylalanine), not much. As a comparison, the amount of phenylalanine in a quarter-pound hamburger is about 1000 mg, or 14 mg kg−1 phenylalanine (70 kg individual), or much more. It is important to keep this fact in mind when considering the authors' arguments, which relate to studies in animals involving extremely high aspartame doses (for example, up to 2000 mg kg−1 in rats, a huge dose). Such studies have no relevance to human use. And, for aspartame to have effects in animals, blood levels of aspartame constituents (aspartate, phenylalanine, methanol) must increase to very high values. At the levels ingested by humans, such increases in blood do not occur, even at high levels of intake (Butchko et al., 2002; Magnuson et al., 2007).

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

References

  • Butchko HH, Stargel WW, Comer CP, Mayhew DA, Benninger C, Blackburn GL et al. (2002). Aspartame: review of safety. Regul Toxicol Pharmacol 35, S1–S93.

    Article  Google Scholar 

  • Fernstrom JD, Fernstrom MH, Massoudi MS (1991). In vivo tyrosine hydroxylation in rat retina: effect of aspartame ingestion in rats pretreated with p-chlorophenylalanine. Am J Clin Nutr 53, 923–929.

    Article  CAS  Google Scholar 

  • Humphries P, Pretorius E, Naude H (2007). Direct and indirect cellular effects of aspartame on the brain. Eur J Clin Nutr; e-pub ahead of print 8 August 2007; doi: 10.1038/sj.ejcn.1602866.

    Article  Google Scholar 

  • Magnuson BA, Burdock GA, Doull J, Kroes RM, Marsh GM, Pariza MW et al. (2007). Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies. Crit Rev Toxicol 37, 629–727.

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Psychiatry and Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA

    J D Fernstrom

Authors
  1. J D Fernstrom
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to J D Fernstrom.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Fernstrom, J. Aspartame effects on the brain. Eur J Clin Nutr 63, 698–699 (2009). https://doi.org/10.1038/ejcn.2008.5

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ejcn.2008.5

This article is cited by

Search

Advanced search

Quick links