Aspartame and the Internet
The following letter appeared in The Lancet on 3 July 1999. It is reproduced here with the permission of the publishers of this respected journal.
Sir - Patients at our diabetes clinic have raised concerns
about information on the internet about a link between the
artificial sweetener aspartame and various diseases. Our
research revealed over 6000 web sites that mention aspartame,
with many hundreds alleging aspartame to be the cause of
multiple sclerosis, lupus erythematosis, Gulf War Syndrome,
chronic fatigue syndrome, brain tumours, and diabetes
mellitus, among many others. Virtually all of the information
offered is anecdotal, from anonymous sources and is
Aspartame, a dipeptide composed of phenylalanine and aspartic
acid linked by a methyl ester bond, is not absorbed, and is
completely hydrolysed in the intestine to yield the two
constituent amino acids and free methanol. Opponents of
aspartame suggest that the phenylalanine and methanol so
released are dangerous. In particular, they assert that
methanol can be converted to formaldehyde and then to formic
acid, and thus cause metabolic acidosis and neurotoxicity.
Although a 330 ml can of aspartame-sweetened soft drink will
yield about 20 mg methanol, an equivalent volume of fruit
juice produces 40 mg methanol, and an alcoholic beverage about
60-100 mg. The yield of phenylalanine is about 100 mg for a
can of diet soft drink, compared with 300 mg for an egg, 500
mg for a glass of milk, and 900 mg for a large hamburger (1).
Thus, the amount of phenylalanine or methanol ingested from
consumption of aspartame is trivial, compared with other
dietary sources. Clinical studies have shown no evidence of
toxic effects and no increase in plasma concentrations of
methanol, formic acid, or phenylalanine with daily consumption
of 50 mg/kg aspartame (equivalent to 17 cans of diet soft
drink daily for a 70 kg adult) (1, 2).
The anti aspartame campaign purports to offer an explanation
for illnesses that are prominent in the public eye. By
targeting a manufactured chemical agent, and combining this
with pseudo-science and selective reporting, the campaign
makes complex issues deceptively simple. Sensational web site
names (eg, aspartamekills.com) grab the browser's attention
and this misinformation is also widely disseminated via chat
groups and chain e-mail.
People consult the internet about medical issues for various
reasons and many users regard online sources as being
authoritative and valid. The medical profession has a role in
teaching our patients to be discriminating consumers of the
information offered there.
Anthony Zehetner, Mark McLean
Department of Endocrinology, Westmead Hospital,
Sydney NSW 2145, Australia
3 July 1999
- Aspartame. In: Gelman C R, Rumack B H, Hess A J, eds. DRUGDEX® System.Englewood, Colorado: MICROMEDEX, 1998. Edition expires 1999.
- Anon. ADA position statement: use of noncaloric sweeteners. Diabetes Care 1991.