ABSTRACT
Toxicology is based on the premise that all compounds are toxic at some dose. Salt, water, sugar, and even a mother’s love produce deleterious effects when given in inappropriate amounts. Since aspartame is a methyl ester, its metabolism releases methanol to the circulation. Ingestion of large doses of methanol is associated with adverse effects in sensitive species. Thus the potential toxicity of aspartame due to its methanol content must be considered. Plasma phenylalanine levels increase after ingestion of meals containing protein, with postprandial plasma phenylalanine levels reaching 12 µmol/dl, or about 2 mg%. A total of 8 subjects heterozygous for phenylketonuria and 12 normal subjects were studied after aspartame administration at a dose of 34 mg/kg body weight. Plasma tyrosine levels in normal subjects were higher 60 minutes after aspartame loading in normal subjects than in heterozygotes. In normal subjects, plasma tyrosine levels remained significantly elevated over base-line levels from 15 minutes to 7 hours.
