[Frontiers in Bioscience S3, 428-444, January 1, 2011]

Maternal amino acid supplementation for intrauterine growth restriction

Laura D Brown1, Alice S Green2, Sean W Limesand2, Paul J Rozance1

1Department of Pediatrics, University of Colorado Denver; Aurora, CO, 2Department of Animal Sciences, University of Arizona; Tucson, AZ

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Amino acid transfer and metabolism
4. Intrauterine growth restriction
5. Protein supplementation to prevent or treat intrauterine growth restriction
6. Postulated mechanisms to explain fetal outcomes from increased protein intake
6.1. Placental transfer of amino acids to the fetus
6.2. Mismatch of increased amino acids with persistently low fetal anabolic hormone concentrations
6.3. Increased oxidative metabolism of extra amino acids
7. Growth promoting effects of specific amino acids
7.1. Arginine
7.2. Taurine
7.3. Leucine
8. Concluding remarks and future directions for amino acid supplementation
9. Acknowledgements
10. References

1. ABSTRACT

Maternal dietary protein supplementation to improve fetal growth has been considered as an option to prevent or treat intrauterine growth restriction. However, in contrast to balanced dietary supplementation, adverse perinatal outcomes in pregnant women who received high amounts of dietary protein supplementation have been observed. The responsible mechanisms for these adverse outcomes are unknown. This review will discuss relevant human and animal data to provide the background necessary for the development of explanatory hypotheses and ultimately for the development therapeutic interventions during pregnancy to improve fetal growth. Relevant aspects of fetal amino acid metabolism during normal pregnancy and those pregnancies affected by IUGR will be discussed. In addition, data from animal experiments which have attempted to determine mechanisms to explain the adverse responses identified in the human trials will be presented. Finally, we will suggest new avenues for investigation into how amino acid supplementation might be used safely to treat and/or prevent IUGR.