Supplementation with human milk protein improves growth of small premature infants fed human milk. Supplementation of pooled human milk with casein hydrolysate: energy and nitrogen balance and weight gain composition in very low birth weight infants. Growth of very low birth weight infants on varying amounts of human milk protein.
We investigated the influence of human milk protein and medium-chain triglyceride supplementations of human milk feedings on the growth of very low birth weight infants during their first weeks of life. A group of 44 preterm infants with birth weights of less than 1,520 g and a mean gestational age of 30.3 weeks was randomly divided into four groups to receive plain human milk or human milk supplemented with human milk protein (0.9 g/dL), with medium-chain triglycerides (1 g/dL), or with both. The medium-chain triglyceride oil supplementation did not influence the growth of these infants. The infants given supplementary protein gained weight faster during weeks 4 to 6 than those without (18.5 +/- 0.7 v 15.1 +/- 0.6 g/kg/d; mean +/- SEM; P = .001). After 4 weeks of age the infants given supplementary protein had a mean weight gain equal to the mean intrauterine rate, in contrast to the infants of the other groups, who grew more slowly until age 6 weeks. Furthermore, we found a correlation between serum albumin concentration and weight gain during the seventh week of life (P = .018). The length growth velocity for the infants with protein supplementation was 0.99 +/- 0.06 cm/wk (mean +/- SEM) and for those without 0.83 +/- 0.05 cm/wk (P = .043). There was no difference in growth of head circumference between the groups. We conclude that human milk protein supplementation improves the growth of small premature infants fed human milk, and that the protein concentration of bank milk is insufficient for their adequate growth. Growth and nitrogen and energy balances were studied with a combined technique of nutrient balance and indirect calorimetry measurement in two groups of eight very low birth weight infants fed pooled pasteurized human milk (HM) or cow's milk casein hydrolysate supplemented HM (HM-Pr). There was no difference in the amount of energy absorbed (91 +/- 17 kcal/kg/day with HM-Pr versus 95 +/- 8 with HM-P) or in the growth rate. The infants fed HM-Pr had a higher nitrogen intake (602 +/- 80 versus 395 +/- 64 mg/kg/day; p less than 0.001), urinary nitrogen excretion (160 +/- 64 versus 78 +/- 16 mg/kg/day; p less than 0.005) and nitrogen retention (326 +/- 32 versus 252 +/- 48 mg/kg/day; p less than 0.01). They also had increased plasma concentrations of essential amino acids, urea nitrogen, and total protein without metabolic imbalance. Energy expenditure was higher (58 versus 49 kcal/kg/day; p less than 0.005) and energy storage lower (33 versus 47 kcal/kg/day; p less than 0.05) with HM-Pr. In percent of weight gain, protein and fat accretion represented 12 and 14% in HM-Pr group versus 10 and 27% in HM group. Very low birth weight infants fed casein hydrolysate supplemented pooled HM achieved a growth rate and a weight gain composition similar to the fetus. In a double-blind, randomized study, 28 healthy, growing very low birth wt, appropriate-for-gestational-age infants were fed human milk, preferably mother's own, fortified daily with human milk protein and/or human milk fat. The infants entered the study when they were stable on complete enteral intakes of 170 mL/kg/d (mean age = 19 d). The study lasted for a mean of 4 wk. Samples from all the milks were collected daily, and intakes of protein, fat, carbohydrates, energy, and electrolytes were calculated weekly during the whole study period. Protein intakes ranged from 1.7 to 3.9 g/kg/d, and energy intakes from 100 to 150 kcal/kg/d. Wt and length gain in the nonprotein-enriched groups were 15.6 +/- 2.7 g/kg/d (mean +/- SD) and 0.88 +/- 0.17 cm/wk; the corresponding figures for the protein-enriched groups were 20.2 +/- 2.1 g/kg/d and 1.24 +/- 0.14 cm/wk. There was a strong correlation between protein intake and growth in wt and length up to an intake of about 3 g/kg/d; more protein did not result in increased growth. The same was true for energy intake, with a maximal growth rate at an intake of about 120 kcal/kg/d. A protein intake of more than 3 g/kg/d resulted in a growth rate equal to or higher than the estimated intrauterine growth rate. Some infants fed mature banked human milk alone had a poor growth. Sodium intake was low, ranging from 1.5 to 2.6 mmol/kg/d. No correlation was found between sodium intake and growth rates.
Protein supplementation of human milk in relatively well preterm infants results in increases in short term weight gain, linear and head growth. Urea levels are increased, which may reflect adequate rather than excessive dietary protein intake. Further research should be directed towards the evaluation of specific levels of protein intake in preterm infants and the clinical effects of supplementation with protein, including long term growth and neurodevelopmental outcomes. This may best be done in the context of refinement of available multicomponent fortifier preparations.