The Role of Metabolomics in Assessing the Nutritional Intervention in Preterm Infant Feeding: A Scoping Review

Parenteral nutrition (PN) is the standard of care for preterm infants to bridge the nutritional gap before enteral nutrition (EN) is established. Current recommendations for PN are largely based on intrauterine nutrient accretion and breast milk constituents. Whether this estimation sufficiently meets the extrauterine metabolic needs of preterm infants remains unclear. This review examines the available evidence on metabolomic outcomes comparing both PN and EN in preterm infants. Only original articles reporting metabolomic outcomes in preterm infants receiving PN and EN were included. After the screening process, six original articles [China (n=1), Norway (n=1), Sweden (n=2), Mexico (n=1), and the USA (n=1)] were selected for this review. The studies examined the metabolomic profiles of 525 infants receiving PN and EN from their serum (n=2), urine (n=3), and dried blood spots (n=1) samples using 1H-NMR (n=4), GC-MS (n=1), UHPLC-MS/MS (n=1) as analytical platforms. Metabolites including glucose, amino acids and short-chain acylcarnitine were upregulated in the biofluids of PN-fed infants, suggesting an oversupply. In contrast, a diverse range of choline, amino acids and lipid metabolites essential for growth and development were enriched in the exclusively EN-fed infants. This scoping review summarised the significant metabolomic differences observed in preterm infants transitioning from parenteral to full enteral feeding. It enhances our understanding of how current nutritional formulations contribute to sufficiency, excess or lack of nutrient assimilation. Future collaborative research should aim to establish a database of age-related reference ranges for essential metabolites. This will aid in developing personalised nutrition tailored to the specific needs of preterm infants, potentially improving their long-term growth and development outcomes.