are not seen in toxicity studies to suggest aspartame can adversely affect neuronal function. As with methanol and aspartic acid, common foods in the typical diet, such as milk, meat, and fruits, will lead to ingestion of significantly higher amounts of phenylalanine than would be expected from aspartame consumption. Cancer Reviews have found no association between aspartame and cancer. This position is supported by multiple regulatory agencies like the FDA and EFSA as well as scientific bodies such as the National Cancer Institute. The EFSA, FDA, and US National Cancer Institute state that aspartame is safe for human consumption. Neurotoxicity symptoms Reviews found no evidence that low doses of aspartame would plausibly lead to neurotoxic effects. A review of studies on children did not show any significant findings for safety concerns with regard to neuropsychiatric conditions such as panic attacks, mood changes, hallucinations, attention deficit hyperactivity disorder (ADHD), or seizures by consuming aspartame. Water quality Aspartame passes through wastewater treatment plants mainly unchanged. Headaches Headaches are the most common symptom reported by consumers. While one small review noted aspartame is likely one of many dietary triggers of migraines, in a list that includes "cheese, chocolate, citrus fruits, hot dogs, monosodium glutamate, aspartame, fatty foods, ice cream, caffeine withdrawal, and alcoholic drinks, especially red wine and beer", other reviews have noted conflicting studies about headaches and other studies lack any evidence and references to support this claim. Mechanism of action The perceived sweetness of aspartame (and other sweet substances like acesulfame potassium) in humans is due to its binding of the heterodimer G protein-coupled receptor formed by the proteins TAS1R2 and TAS1R3. Aspartame is not recognized by rodents due to differences in the taste receptors. Metabolites Aspartame is rapidly hydrolyzed in the small intestine by digestive enzymes which break aspartame down into methanol, phenylalanine, aspartic acid, and further metabolites, such as formaldehyde and formic acid. Due to its rapid and complete metabolism, aspartame is not found in circulating blood, even following ingestion of high doses over 200 mg/kg. Aspartic acid Aspartic acid (aspartate) is one of the most common amino acids in the typical diet. As with methanol and phenylalanine, intake of aspartic acid from aspartame is less than would be expected from other dietary sources. At the 90th percentile of intake, aspartame provides only between 1% and 2% of the daily intake of aspartic acid. Methanol The methanol produced by