Aspartame Issues and Concerns


The artificial sweetener aspartame (Nutrasweet) is a dipeptide composed of two amino acids, aspartic acid and phenylalanine. Amino acids are the building blocks of proteins.

Aspartame is metabolized (broken down) in the body to approximately 50% phenylalanine, 40% aspartic acid, and 10% methanol. The resulting levels of methanol are not significant. The FDA set the Acceptable Daily Intake (ADI) for asparatame at 50 mg/kg . For 99% of the population, daily consumption is less than 35 mg/kg.


In 1996, a study was published suggesting that aspartame may be the causative factor in an increase in the incidence of brain tumors in the US from 1984 to 1985. Asparatame was reased into the market in 1981. However, this temporal (time-related) association does not prove a cause-and-effect relationship. Other studies, using various animal species, have not shown any effect of aspartame on brain tumor development. Also in 1997, the association between aspartame consuption and the development of brain tumors in children was investigaed by other scientists. This study also could find no evidence of an association betwen aspartame consumption and brain tumor development. Therefore, there is no conclusive evidence that aspartame is associated with brain tumor development.


Because phenylalanine is the primary metabolite of aspartame, concern for phenylketonuria (PKU) patients prompted the warning label seen on diet soft drinks.

Anecdotal reports have implicated aspartame in behavioral problems in children. Studies in children to evaluate the possibility of a contribution of aspartame to behavioral disorders such as attention deficit disorder found no effect. There have been claims of aspartame inducing seizures, with a particular focus on airline pilots. However, studies on adults and children have found no association between aspartame and seizure activity. Also, at least one controlled study found no relationship between aspartame and allergic hypersensitivity.

The only ill effect that has been established through a controlled study was an increase in headaches among a group who self-reported headaches after ingestion of aspartame. This study gave aspartame at 30 mg/kg/day. For a 70-kg person (about 154 pounds), this would translate to 2100 mgs of aspartame a day. At 180 mg of aspartame per can of pop (Nutrasweet Corp), that would be the equivalent of drinking about 12 cans of diet pop a day. Indeed, most studies of aspartame use levels of 30 to 75 mg/kg/day, or up to the equivalent of 30 cans of pop a day.

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Prepared Summer 1997 by Bernadene Magnuson, Ph.D.
University of Idaho, Dept. of Food Science and Toxicology - EXTOXNET FAQ Team.