title: Repeated ingestion of aspartame-sweetened beverage: effect on plasma amino acid concentrations in individuals heterozygous for phenylketonuria.
abstract: It has been suggested that excessive use of aspartame (APM) (N-L-alpha-aspartyl-L-phenylalanine methyl ester) might grossly elevate plasma aspartate and phenylalanine concentrations in individuals heterozygous for phenylketonuria (PKUH). In study 1 six adult PKUH (three males; three females) ingested three successive 12-oz servings of beverage at 2-h intervals. The study was carried out in two parts in a randomized crossover design. In one arm the beverage was not sweetened. In the other the beverage provided 10 mg APM/kg body weight per serving. The addition of APM to the beverage did not significantly increase plasma aspartate concentration but did increase plasma phenylalanine levels 2.3 to 4.1 mumol/dL above baseline values 30 to 45 min after each dose. The high mean plasma phenylalanine level after repeated APM dosing (13.9 +/- 2.15 mumol/dL) was slightly, but not significantly, above the normal postprandial range for PKUH (12.6 +/- 2.11 mumol/dL). In study 2 six different adult PKUH ingested beverage providing 30 mg APM/kg body weight as a single bolus. The high mean plasma phenylalanine concentration and the phenylalanine to large neutral amino acid ratio were significantly higher when APM was ingested as a single bolus than when ingested as a divided dose.
authors.affiliation: Department of Pediatrics, University of Iowa College of Medicine, Iowa City.
authors.forename: L D
authors.initials: LD
authors.lastname: Stegink
authors.forename: L J
authors.initials: LJ
authors.lastname: Filer
authors.forename: G L
authors.initials: GL
authors.lastname: Baker
authors.forename: E F
authors.initials: EF
authors.lastname: Bell
authors.forename: E E
authors.initials: EE
authors.lastname: Ziegler
authors.forename: M C
authors.initials: MC
authors.lastname: Brummel
authors.forename: W L
authors.initials: WL
authors.lastname: Krause
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000097:blood*; D001218:Aspartame / Q000008:administration & dosage* / Q000009:adverse effects; D001628:Beverages / Q000009:adverse effects; D001692:Biological Transport; D004151:Dipeptides / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D010649:Phenylalanine / Q000097:blood; D010661:Phenylketonurias / Q000097:blood / Q000235:genetics*; D011897:Random Allocation
chemical_list: D000596:Amino Acids; D004151:Dipeptides; D010649:Phenylalanine; D001218:Aspartame