Sodium and Growth in Preterm Infants: A Review

AIM: This article is intended to review the relationship between sodium homeostasis and growth, outline reasons why preterm infants may become sodium deficient, and share data from our group and others regarding the potential benefits of dietary sodium supplementation. BACKGROUND: Despite tremendous efforts over the past 20 years to optimize neonatal nutrition, postnatal growth failure in preterm infants remains a significant problem. Compelling associations have been identified between in-hospital growth failure and cardiometabolic and neurodevelopmental disorders, heightening the need to further identify the optimal nutritional needs of preterm infants. RESULTS: The impact of sodium deficiency may have on somatic growth is poorly studied and reported upon within the human literature. In contrast, animal studies dating back almost 100 years highlight the nutritional importance of dietary sodium. Sodium homeostasis during early postnatal life is understudied and underappreciated by neonatologists. CONCLUSION: Insufficient sodium intake during early life is likely a critical yet underappreciated contributor to growth failure. Total body sodium depletion may be an important risk factor driving complications of premature birth. CLINICAL SIGNIFICANCE: Increased awareness of sodium homeostasis in preterm infants may improve outcomes in this population. Sodium intake recommendations are provided based on the interpretation of currently available literature.