Abstract
BACKGROUND: Modulation of behavior and physiology by dietary perturbations early in life can provide clues to the pathogenesis of adult diseases. We tested the hypothesis that a period of early protein supplementation modulates sympathetic nervous system activity demonstrated indirectly by an increase in active sleep state distribution in very low birth weight (VLBW) infants. METHODS: VLBW infants (n = 71) were randomized to a total parenteral nutritional regimen providing 18% of the energy intake as amino acids (AA) or a conventional regimen providing 12.5% to achieve targeted AA intakes of 4 g/kg/day (0.004 kcal/kg/day) and 3 g/kg/day (0.003 kcal/kg/day), respectively. Both groups were weaned to enteral feeding and advanced to provide similar AA intake of 4 g/kg/day (0.004 kcal/kg/day). Six-hour daytime, behavioral sleep studies were performed when the infants reached full enteral intake (165 ml/kg/day). RESULTS: Infants in the high protein group spent more time in active sleep (77.2 ± 10.5% vs. 70.7 ± 11.8%), p < 0.01 and less time in quiet sleep (12.9 ± 3.4% vs. 17.7 ± 7.0%, p < 0.01) as compared to the conventional group. No group differences were observed for indeterminate sleep, awake, or crying states. CONCLUSIONS: These results suggest that dietary intake may indirectly influence sympathetic nervous system activity. IMPACT: Infants randomized to an early, high protein nutritional regimen spent an increased percentage of time in active sleep, supporting the hypothesis that nutrition and behavior are interactive. Furthermore, sleep states are an indirect measure of sympathetic nervous system activity, suggesting that dietary intake may influence sympathetic nervous system activity. This study highlights the importance of considering the impact of nutrition during critical periods of development in order to further understand and improve the long-term outcomes of very low birth weight infants.