As of 2014, several clinical studies show that aspartame does not cause cancer, and it is only a health risk for people who suffer from phenylketonuria and are unable to metabolize phenylalanine, according to the American Cancer Society. Studies continue to analyze the possible side effects of aspartame.
Several lab studies performed on animals given extremely high daily doses of aspartame for their entire lives found that the animals never suffered an increased risk of developing cancer or any other form of illness, according to the American Cancer Society. The Food and Drug Administration and European Food Safety Authority analyzed lab results from two Italian studies that linked leukemia and lymphoma in rats to aspartame exposure and found the studies were unreliable. Data related to cancer occurrences in more than 500,000 people was studied by the National Cancer Institute, which found that people exposed to aspartame are not more likely to develop cancer than those who do not consume the ingredient.
Some people claim to experience adverse side effects, such as dizziness, indigestion, mood changes and headaches, after consuming aspartame. Serious diseases have also been linked to aspartame consumption, including diabetes, multiple sclerosis, attention deficit disorder, Alzheimer's disease and seizures. However, as of 2014, the American Cancer Society says there is no scientific evidence available to support the accuracy of these assertions.