Dietary Aromatic Amino Acid Requirements During Early and Late Gestation in Healthy Pregnant Women.
J Nutr
; 150(12): 3224-3230, 2020 12 10.
Article
en En
| MEDLINE
| ID: mdl-33188409
ABSTRACT
BACKGROUND:
Phenylalanine and tyrosine (referred to as total aromatic amino acids; TAAs) are essential for protein synthesis, and are precursors for important catecholamines. Current estimated average requirement (EAR) recommendations for TAA during pregnancy are 36 mg·kg-1·d-1, and has not been experimentally determined.OBJECTIVES:
The aim was to determine TAA requirements (dietary phenylalanine in the absence of tyrosine) during early and late gestation using the indicator amino acid oxidation (IAAO, with L-[1-13C]leucine) technique.METHODS:
Nineteen healthy pregnant women (age 22-38 y) were studied at a range of phenylalanine intakes (5 to 100 mg·kg-1·d-1) in early (13-19 wk) and/or late (33-39 wk) pregnancy for a total of 51 study days. Graded test intakes were provided as 8 hourly isonitrogenous and isocaloric meals. Breath samples were collected for 13C enrichment analysis on an isotope ratio mass spectrometer. A plasma sample was collected and analyzed for phenylalanine and tyrosine concentrations on an amino acid analyzer. The TAA requirement in early and late pregnancy was calculated using 2-phase linear regression crossover analysis that identified breakpoints in 13CO2 production (the requirement) in response to phenylalanine intakes.RESULTS:
TAA requirement during early pregnancy was 44 mg·kg-1·d-1 (95% CI 28.3, 58.8) and during late pregnancy was 50 mg·kg-1·d-1 (95% CI 36.1, 63.1). In early and late pregnancy, plasma phenylalanine and tyrosine concentrations rose linearly in response to graded phenylalanine intakes.CONCLUSIONS:
Our results suggest that the current EAR of 36 mg·kg-1·d-1 for TAAs is underestimated. When compared with results previously determined in nonpregnant adults, early pregnancy requirements were similar (43 compared with 44 mg·kg-1·d-1, respectively). During late pregnancy, a 14% higher TAA requirement was observed when compared with early pregnancy. The results from this study have potential implications for creating gestation stage-specific TAA recommendations.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fenilalanina
/
Tirosina
/
Aminoácidos Aromáticos
/
Mujeres Embarazadas
/
Necesidades Nutricionales
Límite:
Adult
/
Female
/
Humans
/
Pregnancy
Idioma:
En
Revista:
J Nutr
Año:
2020
Tipo del documento:
Article
País de afiliación:
Canadá