Effects of various dietary amino acid preparations for phenylketonuric patients on the metabolic profiles along with postprandial insulin and ghrelin responses.
OBJECTIVE
We investigated the metabolic profiles along with insulin and ghrelin responses following ingestion of various amino acid (AA) substitutes commonly used in the treatment of phenylketonuria to study the effects of added macronutrients.


METHODS
Twenty healthy and 6 phenylketonuric adults ingested AA mixtures with or without carbohydrates and fat (Anamix, Easiphen, or p-am 3; 0.35 g AA/kg body weight); milk powder shakes were used for control purposes. Serum AA, glucose, urea, insulin, and ghrelin were measured over 5 h.


RESULTS
Peak AA concentrations were achieved at around 60 min postprandially for supplemented AA powders and control shakes, significantly later than for pure AA. Of interest, the mean Phe/Tyr ratio declined by 40-50% in phenylketonuric patients following intake of Easiphen, Anamix, or p-am 3. The insulin peaks, up to 500% as compared with baseline, occurred at 30 min and were approximately 100% higher after intake of AA plus macronutrients. Glucose and urea remained constant. Ghrelin showed a nadir at 60 min, followed by a rise leading to a 30% increase of initial concentrations for pure AA as compared with more constant levels for preparations with macronutrients.


CONCLUSIONS
An oral AA bolus together with macronutrients retards hyperaminoacidemia, displays a higher insulin secretion, normoglycemia, and more stable ghrelin concentrations, whereas the pure AA tested here exerted weaker anabolic effects.
Weigel
C
C
Children and Youth Hospital, University of Erlangen-Nurnberg, Erlangen, Germany.
Rauh
M
M
Kiener
C
C
Rascher
W
W
Knerr
I
I
D000284:Administration, Oral; D000328:Adult; D000596:Amino Acids / Q000493:pharmacokinetics*; D019540:Area Under Curve; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004041:Dietary Fats / Q000494:pharmacology*; D005260:Female; D054439:Ghrelin; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008297:Male; D036361:Peptide Hormones / Q000378:metabolism*; D010661:Phenylketonurias / Q000178:diet therapy / Q000378:metabolism*; D019518:Postprandial Period; D014508:Urea / Q000097:blood
D000596:Amino Acids; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones; D014508:Urea