Amino Acid Contents of Infant Formulas

Alegrı́a, Amparo; Barberá, Reyes; Farré, R.; Lagarda, Marı́a Jesús; López, Juan C.

doi:10.1006/jfca.1999.0818

Cited by 13 publications

(9 citation statements)

References 12 publications

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“…Interestingly, this is also the first study that measured free tryptophan in multiple random samples of popular infant formulas in North America. Previous reports of free amino acids in infant formulas evaluated 1 random sample in each of 8 different brands in North America (Ventura et al, 2012) and 1 sample per 18 different brands available in Spain (Alegria et al, 1999); however their results, from a non-statistical perspective, have a similar rank of effect (amongst extensively hydrolyzed, partially hydrolyzed and non-hydrolyzed formulas) to our statistically supported observations. L-Tryptophan has been helpful with mild insomnia and decreasing latency to fall asleep, but has not been investigated for sleeping difficulties specifically in postpartum.…”

Section: Discussionsupporting

confidence: 83%

No effect of oral l-tryptophan or alpha-lactalbumin on total tryptophan levels in breast milk

Dowlati

Ravindran

Maheux

et al. 2015

European Neuropsychopharmacology

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Section: Discussionsupporting

confidence: 83%

No effect of oral l-tryptophan or alpha-lactalbumin on total tryptophan levels in breast milk

Dowlati

Ravindran

Maheux

et al. 2015

European Neuropsychopharmacology

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“…The determined mean phenylalaninerequirement estimates are approximately twice as low as the contents of term and preterm formulae currently on the market (55). Both estimates are part of a large project determining the requirement of all essential amino acid of term and preterm neonates.…”

Section: Discussionmentioning

confidence: 93%

“…The application of this ratio to our phenylalanine-requirement estimates results in a tyrosine requirement of 39 and 53 mg/kg per day for term and preterm infants, respectively. In currently available formulae, approximately twice that amount is provided (55). Therefore, we speculate that, in future formulae, the tyrosine content can also be lowered.…”

Section: Discussionmentioning

confidence: 99%

Phenylalanine requirements of enterally fed term and preterm neonates

Hogewind-Schoonenboom¹,

Zhu²,

Lin³

et al. 2015

The American Journal of Clinical Nutrition

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Background: Phenylalanine, which is an essential aromatic amino acid, is either used for protein synthesis or irreversibly hydroxylated to tyrosine. The provision of optimal amounts of dietary phenylalanine is not only important for growth and development but might also influence catecholamine synthesis and release rates. The current recommended aromatic amino acid requirement for infants aged 0-6 mo is based on the amino acid content of human milk. Objective: We quantified the requirements for phenylalanine in the presence of excess tyrosine (166 or 177 mg/kg per day for term and preterm infants, respectively) for term and preterm neonates by using the indicator amino acid oxidation method with L-[1-13 C]lysine 2HCl as an indicator. Hence, we determined the minimum obligatory phenylalanine requirement. Design: Fully enterally fed term and preterm infants received randomly graded amounts of phenylalanine (5-177 mg/kg per day) as part of an elemental formula. Data are expressed as means 6 SDs. Results: Twenty term (birth weight: 3.19 6 0.34 kg; gestational age: 38.9 6 1 wk) and 16 preterm (birth weight: 1.75 6 0.17 kg; gestational age: 32.5 6 0.6 wk) Asian infants participated at a postnatal age of 17 6 8 d. In total, 44 studies were performed. The minimum obligatory phenylalanine requirement was 58 mg/kg per day (95% CI: 38-78 mg/kg per day) and 80 mg/kg per day (95% CI: 40-119 mg/kg per day) for term and preterm infants, respectively. Conclusion: The determined mean phenylalanine-requirement estimates are lower than the contents of term and preterm formulas currently on the market. This trial was registered at www. trialregister.nl as NTR1610.

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“…Ion exchange chromatography (IEC) with fluorescence detection was also employed to determine TRP in pure proteins and feedstuffs [20], but IEC needed post-column derivatization with o-phthalaldehyde (OPA), thus resulting in further time-and chemical-consuming steps. The determination of tryptophan in infant formula by high performance liquid chromatography (HPLC) with UV detection (λ = 254 nm) needed a derivatization step, with phenylisothiocyanate (PITC), in addition to the protein hydrolysis prior to the HPLC analysis [21,22]. Derivatization was necessary due to the poor absorbance of TRP in the UV spectral region, but this could result in a time-and chemicals-consuming procedure.…”

Section: Introductionmentioning

confidence: 99%

Rapid Determination of Total Tryptophan in Yoghurt by Ultra High Performance Liquid Chromatography with Fluorescence Detection

Ritota

Manzi

2020

Molecules

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Tryptophan (TRP) is an essential amino acid which cannot be synthesized by humans and animals, but has to be supplied by exogenous sources, notably through the diet. The bulk of dietary TRP flows into the synthesis of body’s proteins, but the TRP metabolism also involves several biochemical reactions (i.e., serotonin and kynurenine pathways). Defects in the TRP transport mechanism or catabolism are related to a large number of clinical abnormalities. Therefore, dietary TRP intake is necessary not only for the body’s growth but also for most of the body’s metabolic functions. Among protein-based foods, milk proteins provide a relatively high amount of TRP. In this paper, a rapid chromatographic method for TRP determination in yoghurt, by ultra high performance liquid chromatography on a reversed-phase column with fluorescence detection (280 nm Ex; 360 nm Em), is provided. A linear gradient elution of acetonitrile in water allowed TRP analysis in 8.0 min. The limit of detection and limit of quantification of the method were 0.011 ng/µL and 0.029 ng/µL, respectively, using 5-methyl L-tryptophan as the internal standard. The analytical method was successfully applied to commercial yoghurts from different animal species, and the TRP values ranged between 35.19 and 121.97 mg/100 g (goat and cow Greek type yoghurt, respectively).

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Amino Acid Contents of Infant Formulas

Cited by 13 publications

References 12 publications

No effect of oral l-tryptophan or alpha-lactalbumin on total tryptophan levels in breast milk

No effect of oral l-tryptophan or alpha-lactalbumin on total tryptophan levels in breast milk

Phenylalanine requirements of enterally fed term and preterm neonates

Rapid Determination of Total Tryptophan in Yoghurt by Ultra High Performance Liquid Chromatography with Fluorescence Detection

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