Fortification of human milk: evaluation of a novel fortification scheme and of a new fortifier.

Human milk fed to very-low-birth-weight infants must be fortified with protein, minerals, and vitamins. We tested a new fortification regimen in which the amount of fortifier was adjusted on the basis of frequent determinations of serum urea nitrogen (SUN). A newly formulated fortifier based on bovine milk proteins was employed either in the new fashion (regimen ADJ) or in the conventional fixed proportion (regimen FIX). Using the fixed proportion, the study also compared the new fortifier with a fortifier based on human milk protein (regimen HMP). Twelve infants were studied with each of the three regimens; nearly all completed 3 weeks of study. Protein intake was generally higher in ADJ than FIX; the difference was significant (p < 0.01) during week 2. Weight gain was somewhat (but not significantly) greater in regimen ADJ (32.3 g/d or 18.8 g/kg/d) than in regimen FIX (30.0 g/d or 18.3 g/kg/d). SUN was higher in ADJ than in FIX, and several other serum chemical values (calcium, phosphorus, potassium) tended to be higher, probably reflecting higher intakes of these nutrients with ADJ than with FIX. Plasma concentrations of several amino acids were higher in ADJ than FIX, but none, including threonine, were outside the physiological range. In comparing regimen FIX to regimen HMP, infants on FIX received similar intakes of protein and showed slightly but not significantly more rapid weight gain. Concentrations of SUN were lower with FIX, but other serum chemical values, including amino acids, were generally similar to HMP. We conclude that use of the new adjustable fortification regimen is feasible and safe and that it should be studied further. It produced the expected increases in nutrient intakes and growth. The new bovine milk-based fortifier appears to be equivalent to the human milk-based fortifier.

Growth, serum biochemistries, and amino acids of term infants fed formulas with amino acid and protein concentrations similar to human milk.

We tested the hypothesis that amino acid intake from infant formulas modified to be similar to human milk would result in indices of protein metabolism more like those in human milk-fed infants. Formula-fed infants received for 12 weeks one of three isocaloric formulations of a whey-adapted formula that differed in protein concentration: 11, 13, or 15 g/L. Infants consumed similar volumes of formula or human milk. Serum urea nitrogen concentrations reflected the protein content of the diets. Plasma indices of protein nutritional status were normal and did not differ among groups. Growth rates of all infants were normal and similar. Serum indicators of protein nutritional status varied with age, which made comparisons of formula-fed infants with human milk-fed infants difficult. Plasma concentrations of leucine and isoleucine at 4 weeks of age were higher in infants fed the formula containing 15 g protein/L when compared with those of infants fed the other two formulas or human milk. At 8 and 12 weeks of age, all formula-fed infants had plasma amino acid profiles that did not differ significantly from each other except for isoleucine, which was lower in the 11-g/L group. We found that providing formulas with an amino acid pattern similar to that of human milk did not produce a plasma amino acid pattern identical to that of the breast-fed infant. This observation suggests that other factors, such as the hormonal response to feeding, differing nutritional bioavailability of amino acids from human and bovine milk proteins, and the changing quantity and type of amino acids with advancing lactation, influence plasma amino acid concentrations.

Cord blood amino acid concentrations from neonates of 23-41 weeks gestational age.

Amino acid concentrations were measured in the cord blood serum from neonates following 23-41 weeks gestation. These values were then correlated with the gestational age of the newborns. A significant (p less than 0.05) correlation was observed with the concentrations of six amino acids, and five of these correlations were negative. The significance of these normative data are discussed and compared with currently available cord blood aminogram data.

Pregnancy outcome in North American women. I. Effects of diet, cigarette smoking, and psychological stress on maternal weight gain.

This study examined the roles of diet, cigarette smoking, and psychological stress in pregnancy weight gain. The 60 were selected by defined criteria to minimize variation in anthropometric, socioeconomic, and medical variables which also affect weight gain. To maximize variation in weight gain, subjects were also selected on the basis of low weight gain (less than or equal to 15 lb) and adequate weight gain (greater than 15 lb). Each weight gain group contained smokers and nonsmokers. Smokers consumed more calories than nonsmokers (2119 versus 1810 kcal/day, p less than 0.01). for nonsmokers, differences between the intakes of low weight gain (1617 kcal/day) and adequate weight gain (1905 kcal/day) women were significant (p less than 0.02) and calorie intake was correlated with weight gain (r=0.44 p, less than 0.02). Psychological stress negatively correlated with weight gain (r=0.37, p less than 0.01) but not with calorie intake. We conclude that low weight gain is associated with a lower food intake. In contrast, smoking and stress may cause low weight gain by reducing the utilization of calories for weight gain.

Pregnancy outcome in North American women. II. Effects of diet, cigarette smoking, stress, and weight gain on placentas, and on neonatal physical and behavioral characteristics.

This study evaulated the effects of diet, weight gain (low = LWG, less than or equal to 15 lb; adequate greater than 15 lb), smoking, and stress on the pregnancy outcomes of 60 women. LWG mothers, compared to adequate weight gain, had lower calorie intakes, shorter gestations (0.5 wk, Dubowitz) smaller placentas (345 +/- 65 versus 373 +/- 75 g), and infants with lower birth weight 2640 +/- 329 versus 3192 +/- 307 g), ponderal indices (2.37 versus 2.62), and growth rates. Mothers who smoked had increased calorie intake, but showed no alterations in gestational age of infants or placenta weights. Infants of smokers weighed less than those of nonsmokers (2875 +/- 522 versus 309 +/- 511 g), but had a normal ponderal index. LWG or smoking were associated with impaired motor performance, visual habituation and orientation, and reflexes. Smoking adversely affected auditory habituation and orientation, and autonomic regulation. LWG and smoking have significant, but separate, detrimental effects on pregnancy outcome.