Aspartame-sweetened beverage: effect on plasma amino acid concentrations in normal adults and adults heterozygous for phenylketonuria.
Twelve normal subjects ingested either unsweetened beverage (n = 6) or beverage providing 4 mg/kg body weight as aspartame (APM) (n = 6). Neither beverage had any significant effect on plasma aspartate or phenylalanine concentrations. After this study, eight normal and six obligate phenylketonuric (PKU) heterozygous adults each ingested a 354-mL (12-oz) beverage serving on two occasions in a randomized cross-over design. On one occasion the beverage was not sweetened; on the other occasion, the beverage provided 10 mg APM/kg body weight. Plasma amino acid concentrations were measured throughout the 2-h study period. The addition of 10 mg APM/kg body weight to the beverage had no significant effect on plasma aspartate concentration. APM ingestion increased plasma phenylalanine levels of normal subjects from a mean +/- SD baseline value of 5.09 +/- 0.82 mumol/dL to a high mean value of 6.73 +/- 0.75 mumol/dL. In PKU heterozygous subjects the plasma phenylalanine level increased from a mean +/- SD of 9.04 +/- 1.71 to a high mean value of 12.1 +/- 2.08 mumol/dL. The data indicate ready metabolism of the aspartate and phenylalanine portion of APM when administered at levels likely to be ingested by individuals who drink diet beverages.
D000328:Adult; D000596:Amino Acids / Q000097:blood*; D001216:Asparagine / Q000097:blood; D001218:Aspartame / Q000008:administration & dosage / Q000494:pharmacology*; D001224:Aspartic Acid / Q000097:blood; D001628:Beverages; D001692:Biological Transport; D004151:Dipeptides / Q000494:pharmacology*; D005260:Female; D005971:Glutamates / Q000097:blood; D018698:Glutamic Acid; D005973:Glutamine / Q000097:blood; D006579:Heterozygote; D006801:Humans; D007700:Kinetics; D008297:Male; D010649:Phenylalanine / Q000097:blood; D010661:Phenylketonurias / Q000097:blood* / Q000235:genetics; D014443:Tyrosine / Q000097:blood
D000596:Amino Acids; D004151:Dipeptides; D005971:Glutamates; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D014443:Tyrosine; D010649:Phenylalanine; D001216:Asparagine; D001218:Aspartame