Phenylalanine requirements of enterally fed term and preterm neonates

Hogewind-Schoonenboom, Jacomine E.; Zhu, Li; Lin, Zhenguo; Ackermans, Eveline C. A. M.; Mulders, Renske; Boekhorst, Bart te; Wijnen, Mandy; Bijnevelt, Lianne; Voortman, Gardi; Schierbeek, Henk; Huang, Lisi; Groof, Femke de; Vermes, András; Chen, Chao; Huang, Ying; Goudoever, Johannes B. van

doi:10.3945/ajcn.114.089664

Cited by 13 publications

(5 citation statements)

References 51 publications

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“…One determined phenylalanine requirements in the presence of excess tyrosine in adult males to be 9.1 mg • kg −1 • d −1 (14). The other determined the minimum phenylalanine requirements in enterally fed term and preterm neonates to be 58 mg • kg −1 • d −1 and 80 mg • kg −1 • d −1 , respectively (38). It will be beneficial to determine TAA requirements in healthy human pregnancy, which will help update the DRI recommendations, and to set recommendations in women with mPKU, because tyrosine is an indispensable amino acid in this population.…”

Section: Discussionmentioning

confidence: 99%

Dietary phenylalanine requirements during early and late gestation in healthy pregnant women

Ennis

Rasmussen

Lim

et al. 2020

The American Journal of Clinical Nutrition

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Background Phenylalanine is an indispensable amino acid and, via tyrosine, is the precursor for the neurotransmitters dopamine, norepinephrine, and epinephrine. Currently, dietary requirements for phenylalanine during pregnancy are unknown. Objectives This study's aim was to determine phenylalanine requirements (in the presence of excess tyrosine) during early and late gestation using direct amino acid oxidation (DAAO; with l-[1-13C]phenylalanine) and indicator amino acid oxidation (IAAO; with l-[1-13C]leucine). Methods Twenty-three healthy women (age: 30.4 ± 3.1 y, mean ± SD) were studied at a range of phenylalanine intakes (5.5–30.5 mg · kg−1 · d−1 in early and late pregnancy using DAAO, and 2.5–30.5 mg · kg−1 · d−1 in late pregnancy using IAAO) for a total of 76 study days. Test intakes were provided as 8 isocaloric and isonitrogenous meals with 1.5 g · kg−1 · d−1 protein and energy at 1.7 times the measured resting energy expenditure. Breath samples were analyzed on an isotope ratio mass spectrometer for 13C enrichment. Phenylalanine requirement was determined using a 2-phase linear regression crossover model to identify a breakpoint in 13CO2 production (representing the mean requirement) in response to phenylalanine intakes. Results Phenylalanine requirement during early pregnancy was determined to be 15 mg · kg−1 · d−1 (95% CI: 10.4, 19.9 mg · kg−1 · d−1); during late pregnancy, it was determined to be 21 mg · kg−1 · d−1 by DAAO (95% CI: 17.4, 24.7 mg · kg−1 · d−1) and IAAO (95% CI: 10.5, 32.2 mg · kg−1 · d−1). Conclusions Our results suggest a higher requirement (40%) for phenylalanine during late pregnancy than during early pregnancy. Moreover, the early pregnancy requirements are higher than the previous adult male requirement (9.1 mg · kg−1 · d−1; 95% CI: 4.6, 13.6 mg · kg−1 · d−1), although the 95% CIs overlap. Both DAAO and IAAO methods provided similar breakpoints in late pregnancy, showing that the DAAO method was appropriate even though low phenylalanine intakes could not be tested. These results have potential implications for gestation stage–specific dietary phenylalanine recommendations in future. This trial was registered at clinicaltrials.gov as NCT02669381.

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Section: Discussionmentioning

confidence: 99%

Dietary phenylalanine requirements during early and late gestation in healthy pregnant women

Ennis

Rasmussen

Lim

et al. 2020

The American Journal of Clinical Nutrition

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“…Animal-based food production generally has a bigger climate impact than plant-based From the introduction of the first infant formula onwards, milk protein and its processes have been optimized to provide the most optimal amino acid profiles in infant formula. However, based on requirement studies [45][46][47][48][49][50], there is still no intact protein to provide the right composition of essential amino acids. Therefore, the addition of free amino acids is unavoidable, which has its disadvantages.…”

Section: Plant Protein-based Infant Formulamentioning

confidence: 99%

Low-Protein Infant Formula and Obesity Risk

Kouwenhoven

Muts²,

Finken³

et al. 2022

Nutrients

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Infant formulas have been designed to mimic human milk for infants who cannot be breastfed. The overall goal is to establish similar functional outcomes to assure optimal growth, development, maturation of the immune system, and programming of the metabolic system. However, after decades of improving infant formula, growth patterns and body composition development are still different in formula-fed infants compared to breastfed infants, which could contribute to an increased risk of obesity among formula-fed infants. It has been hypothesized that the lower protein concentration of breast milk compared to infant formula influences infants’ growth and body composition. Thus, several trials in formula-fed infants with different protein intake levels have been performed to test this hypothesis. In this review, we discuss the current evidence on low-protein infant formula and obesity risk, including future perspectives and implications.

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“…To date, the amino acids provided by infant formula have been roughly based on the average amino acid content in human milk (15). In a series of studies, we used the indirect amino acid oxidation (IAAO) technique to assess infant amino acid requirements and showed that infant formulas are likely to provide an excess and unbalanced amount of essential amino acids (16)(17)(18)(19)(20)(21). Based on these outcomes, a modified infant formula was developed with an optimized amino acid composition that facilitated a protein content reduction of 20%.…”

Section: Introductionmentioning

confidence: 99%

A modified low-protein infant formula supports adequate growth in healthy, term infants: a randomized, double-blind, equivalence trial

Kouwenhoven

Antl

Finken

et al. 2020

The American Journal of Clinical Nutrition

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Background A high protein intake in early life is associated with a risk of obesity later in life. The essential amino acid requirements of formula-fed infants have been reassessed recently, enabling a reduction in total protein content and thus in protein intake. Objectives We aimed to assess the safety of an infant formula with a modified amino acid profile and a modified low-protein (mLP) content in healthy term-born infants. Outcomes were compared with a specifically designed control (CTRL) infant formula. Methods In this double-blind, randomized controlled equivalence trial, infants received either mLP (1.7 g protein/100 kcal; n = 90) or CTRL formula (2.1 g protein/100 kcal; n = 88) from enrollment (age ≤ 45 d) to 6 mo of age. A breastfed group served as a reference (n = 67). Anthropometry and body composition were determined at baseline, 17 wk (including safety blood parameters), and 6 mo of age. The primary outcome was daily weight gain from enrollment up until the age of 17 wk (at an equivalence margin of ±3.0 g/d). Results Weight gain from baseline (mean ± SD age: 31 ± 9 d) up to the age of 17 wk was equivalent between the mLP and CTRL formula groups (27.9 and 28.8 g/d, respectively; difference: −0.86 g/d; 90% CI: −2.36, 0.63 g/d). No differences in other growth parameters, body composition, or in adverse events were observed. Urea was significantly lower in the mLP formula group than in the CTRL formula group (−0.74 mmol/L; 95% CI: −0.97, −0.51 mmol/L; P < 0.001). Growth rates, fat mass, fat-free mass, and several essential amino acids were significantly higher in both formula groups than in the breastfed reference group. Conclusions Feeding an infant formula with a modified amino acid profile and a lower protein content from an average age of 1 mo until the age of 6 mo is safe and supports an adequate growth, similar to that of infants consuming CTRL formula. This trial was registered at www.trialregister.nl as Trial NL4677.

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Phenylalanine requirements of enterally fed term and preterm neonates

Cited by 13 publications

References 51 publications

Dietary phenylalanine requirements during early and late gestation in healthy pregnant women

Dietary phenylalanine requirements during early and late gestation in healthy pregnant women

Low-Protein Infant Formula and Obesity Risk

A modified low-protein infant formula supports adequate growth in healthy, term infants: a randomized, double-blind, equivalence trial

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