Published online February 29, 2008
PEDIATRICS Vol. 121 No. 3 March 2008, pp. 655-656 (doi:10.1542/peds.2007-3786)

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LETTER TO THE EDITOR

Effects of Two Different Doses of Amino Acid Supplementation on Growth and Blood Amino Acid Levels in Premature Neonates Admitted to the Neonatal Intensive Care Unit: A Randomized, Controlled Trial

Iolanda Minoli, MD
Department of Perinatology
Macedonio Melloni Maternity Hospital
Milan, Italy

Niels C. Räihä, MD
Department of Pediatrics
University of Lund
Lund, Sweden

To the Editor.—

We read with great interest the article by Clark et al¹ on the effects of parenteral amino acid administration to premature infants at 2 different doses (2.5 g/kg per day and 3.5 g/kg per day). In their multicenter study the authors demonstrated that higher parenteral supplementation of amino acids in premature neonates admitted to the neonatal intensive care unit (NICU) does not improve growth and may be unsafe.

These results support our earlier publications on enteral nutrition, unfortunately neither mentioned nor referred to in the above mentioned article by Clark et al¹ Our studies showed that in low-birth weight infants high-protein formulas providing 4.5g/kg per day result in a higher concentration of amino acids than do either low-protein formulas (2.25g/kg per day) or pooled human milk (1.7g/kg per day). Low-birth weight infants have a limited capacity to metabolize a number of amino acids, especially the sulfur-containing amino acid methionine and the aromatic amino acids tyrosine and phenylalamine^2–4 and have a limited capacity for expansion of urea production for some time after birth.⁵ Moreover, our studies showed that formula-fed low-birth weight infants tend to have higher total serum proteins and to be slightly more acidotic than infants fed on human milk.⁶

We have also reported that formulas with "low" protein content were more suitable for the term infant than some current formulas which provide excessive protein intakes after the first months of life.^7,8

The recent article by Clark et al¹ agrees with the results of our earlier studies and emphasizes the concept that an excess of proteins both in term and preterm infants is not used by the infant and may be responsible for metabolic imbalance.

REFERENCES

1. Clark RH, Chace DH, Spitzer AR. The effects of two different doses of amino acid administration on growth and blood amino acids in premature neonates admitted to the NICU: a randomized, controlled trial. Pediatrics.2007; 120 (6):1286 –1296[Abstract/Free Full Text]
2. Rassin DK, Gaull GE, Heikonen K, et al. Milk protein quantity and quality in low-birth-weight infants. II. Effects on selected aliphatic amino acids in plasma and urine. Pediatrics.1977; 59 (3):407 –422[Abstract/Free Full Text]
3. Rassin DK, Gaull GE, Räiha NCR, et al. Milk protein quantity and quality in low-birth-weight infants. IV. Effects on tyrosine and phenylalamine in plasma and urine. J Pediatr.1977; 90 (3):356 –360[CrossRef][Web of Science][Medline]
4. Gaull GE, Rassin DK, Räihä NCR et al. Milk protein quantity and quality in low-birth-weight infants. III. Effects on sulfur amino acid in plasma and urine. J Pediatr.1977; 90 (3):348 –355[CrossRef][Web of Science][Medline]
5. Boehm G, Mueller DM, Beyreiss K, Räihä NCR. Evidence for functional immaturity of the ornithine-urea cycle in very-low-birth-weight infants. Biol Neonate.1988; 54 (3):121 –125[Medline]
6. Järvenpää A-L, Räihä NCR, Rassin DK, Gaull GE. Feeding the low-birth-weight infant: I Taurine and cholesterol supplementation of formula does not effect growth and metabolism. Pediatrics.1983; 71 (2):171 –178[Abstract/Free Full Text]
7. Räihä NCR, Minoli I, Moro G. Milk protein intake in the term infant. I. Metabolic responses and effects on growth. Acta Paediatr Scand.1986; 75 (6):881 –886[Medline]
8. Räihä NCR, Minoli I, Moro G, Bremer HJ. Milk protein intake in the term infant. II. Effects on plasma amino acid concentrations. Acta Paediatr Scand.1986; 75 (6):887 –892[Medline]

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PEDIATRICS (ISSN 1098-4275). ©2008 by the American Academy of Pediatrics

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This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Minoli, I. Articles by Räihä, N. C. Search for Related Content PubMed PubMed Citation Articles by Minoli, I. Articles by Räihä, N. C. Related Collections Premature & Newborn Social Bookmarking                         What's this?