Aspartame: methanol and the public health

Aspartame (L-asparty-L-phenylalanine methyl ester), a new sweetener marketed under the trade name NutraSweet*, releases into the human bloodstream one molecule of methanol for each molecule of aspartame consumed. This new methanol source is being added to foods that have considerably reduce caloric content and, thus, may be consumed in large amounts. Generally, none of these foods could be considered dietary methanol sources prior to addition of aspartame. When diet sodas and soft drinks, sweetened with aspartame, are used to replace fluid loss during exercise and physical exertion in hot climates, the intake of methanol can exceed 250 mg/day or 32 times the Environmental Protection Agency's recommended limit of consumption for this cumulative toxin. There is extreme variation in the human response to acute methanol poisoning, the lowest recorded lethal oral dose being 100 mg/kg with one individual surviving a dose over ninety times this leve1 55. Humans, due perhaps to the loss of two enzymes during evolution, are more sensitive to methanol than any laboratory animal; even the monkey is not generally accepted as a suitable animal mode142. There are no human or mammalian studies to evaluate thepossible mutagenic, teratogenic, or carcinogeni