According to both the U.S. Food and Drug Administration (FDA) and the European Commission's Scientific Committee on Food state that some minor health effects are possible in high doses. Despite this research, a number of urban myths still exist regarding the side effects of aspartame.
According to the "Journal of Nutritional Biochemistry," 10 percent of aspartame is broken down into methanol in the intestines. Methanol does have the possibility of disrupting physiological processes in the human body; however, the amount is too small to cause damage.
Fifty percent of aspartame is broken down into an amino acid within the body. The phenylalanine created has been shown to cause seizures and changes in neurotransmitter levels in the brain. Again, the levels of consumption must be very high to create this effect.
The average diet beverage drinker in the United States consumes 200mg aspartame per day, according to the National Cancer Institute. To surpass the 3,750 mg limit put forth by the FDA, a consumer would have to drink 21 cans of diet soda.
According to the Institute of Food Technologists, a number of consumers describe aspartame as containing an unpleasant aftertaste. Some people feel it has no flavor, while others compare it to water.