Many claims state that aspartame consumption leads to headaches, indigestion, diabetes, Alzheimer's disease, multiple sclerosis, dizziness and mood disorders, but as of 2014, the American Cancer Society states there is no scientific evidence available to support the validity of these assertions. Aspartame does not pose a threat to the health of people unless they suffer with phenylketonuria. The U.S. Food and Drug Administration considers aspartame to be safe.
People born with phenylketonuria are unable to break down phenylalanine, which is an amino acid found in aspartame. It is necessary for these patients to strictly limit their exposure to the compound to avoid any risk of developing brain malfunctions. Many international scientific studies assess the effects of heavy aspartame dosage in lab animals to test for tumor growth and other related health complications, but the American Cancer Society states none of these studies indicate the substance is unsafe for human consumption.
The U.S. Food and Drug Administration and the European Food Safety Authority both disagree with the results of two Italian studies that suggest leukemias and lymphomas in lab rats are exacerbated by high levels of exposure to aspartame, notes the American Cancer Society. Data sets from human studies also do not show sufficient evidence that aspartame increases the risk of developing lymphomas, leukemias or brain tumors.