Some effects of nutrition on growth and metabolism in the newborn infant
The literature of the history of feeding the low birth weight infant and parenteral nutrition in the newborn was reviewed. Ultra micro methods for the measurement of glucose, lactate, pyruvate, acetoacetate, 3-hydroxybutyrate, alanine and glycerol were described which make measurement of these substances using capillary blood samples possible, and permit longitudinal study of infants with nutritional problems. A study of test weighing in newborn infants demonstrated the inaccuracy of test weighing as a procedure for the determination of feed intake and the importance of the development of accurate baby scales for the measurement of body weight in low birth weight infants. No clear advantage for either continuous jejunal or intermittent gastric feeding was demonstrated in the first 3 weeks of life in a study of these enteral feeding methods in infants of 1.5 kg. or less at birth. If nasojejunal feeding was continued, a slower rate of growth ensued than that of infants fed gastrically. The significance and possible explanations for these observations was discussed. Metabolic studies of low birth weight infants fed continuously by the transpyloric or nasogastric route showed no differences in metabolic profile. Considerable fluctuations of the levels of hormones and metabolites took place despite the continuous infusion of milk. Continuous enteral feeding did not abolish hormone and metabolite fluctuations thought to be of significance in promoting optimal growth. A study of two alternative regimens of total parenteral nutrition in infants with surgical gastrointestinal problems showed that there were greater fluctuations in metabolite levels in infants receiving nutrients sequentially than in infants to whom the nutrients were given continously. Intrahepatic cholestasis occurred more frequently in infants on the sequential (intermittent) regimen but weight gain-was similar with the two regimens. The significance of these findings in relation to the current literature was discussed and conclusions drawn.