The Interaction between Diet and Neurobehavior in Very Low Birth Weight Infants

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 grams/kilogram/day (0.004 kilocalories/kilogram/day) and 3 grams/kilogram/day (0.003 kilocalories/kilogram/day) respectively. Both groups were weaned to enteral feeding and advanced to provide similar AA intake of 4 grams/kilogram/day (0.004 kilocalories/kilogram/day). Six-hour daytime, behavioral sleep studies were performed when the infants reached full enteral intake (165 milliliters/kilogram/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.