Aspartame Causes Cancer in Rats
Copyright 2005 Daily News Central
Rats given varying doses of aspartame -- the second most widely
used artificial sweetener in the world -- experienced a
statistically significant increase in the incidence of malignant
tumors, lymphomas and leukemias in a study slated for
publication in Environmental Health Perspectives.
The study's authors are calling for an "urgent re-evaluation" of
the current guidelines for consumption of this compound.
"Our study has shown that aspartame is a multipotential
carcinogenic compound whose carcinogenic effects are also
evident at a daily dose of 20 milligrams per kilogram (mg/kg) of
body weight," the authors write, "notably less than the current
acceptable daily intake for humans." Currently, the acceptable
daily intake for humans is set at 50 mg/kg in the United States
and 40 mg/kg in Europe.
More Than 200 Million People
Aspartame is found in more than 6,000 products, including
carbonated and powdered soft drinks, hot chocolate, chewing gum,
candy, desserts, yogurt and tabletop sweeteners, as well as some
pharmaceutical products like vitamins and sugar-free cough drops.
More than 200 million people worldwide consume the sweetener. It
has been used for more than 30 years, having first been approved
by the Food and Drug Administration (FDA) in 1974.
Earlier research on the carcinogenicity of aspartame performed
by its producers has been negative.
In the latest study, investigators administered aspartame to
rats by adding it to a standard diet. They began studying the
rats at eight weeks of age and continued until the spontaneous
death of each rat. This study followed more animals over a
longer period than did earlier research.
Treatment groups received feed that contained concentrations of
aspartame at dosages simulating human daily intakes of 5,000,
2,500, 500, 100, 20 and 4 mg/kg body weight. Groups consisted of
100 males and 100 females at each of the three highest dosages,
and 150 males and 150 females at all lower dosages, as well as
controls.
The experiment ended after the death of the last animal at 159
weeks. At spontaneous death, each animal underwent examination
for microscopic changes in all organs and tissues, a process
different from the aspartame studies conducted 30 years ago and
one that was designed to allow aspartame to fully express any
carcinogenic potential.
Extensive Evidence of Malignancies
The treated animals showed extensive evidence of malignant
cancers, including lymphomas, leukemias and tumors at multiple
organ sites in both males and females.
The increase in lymphomas and leukemias may be related to one of
the metabolites in aspartame -- namely methanol -- which is
metabolized in both rats and humans to formaldehyde, the authors
speculate. Both methanol and formaldehyde have shown links to
lymphomas and leukemias in other long-term experiments.
"In our opinion, previous studies did not comply with today's
basic requirements for testing the carcinogenic potential of a
physical or chemical agent, in particular concerning the number
of rodents for each experimental group (40-86, compared to
100-150 in the current study) and the termination of previous
studies at only 110 weeks of age of the animals," the authors
conclude.