Comparison of the B vitamin composition of milk from mothers of preterm and term babies.

Samples of milk were taken at intervals during lactation from 35 mothers of term and 26 mothers of preterm infants and assayed for 8 B complex vitamins. Both term and preterm milks varied widely in vitamin content between mothers. Mean concentrations of thiamin, vitamin B6, nicotinic acid, pantothenic acid, biotin, and folic acid increased progressively over several weeks after parturition but vitamin B12 concentrations declined generally and riboflavin values showed little change. Preterm milk was not richer in vitamins than term milk of the corresponding stage of lactation and it appeared that intake of B vitamins differed widely among preterm infants given their own mothers'' milk. These infants may have meagre body reserves and an increased need for vitamins, and breast milk whether from their own mother or from the milk bank may not meet their needs. There is a strong case for supplementing breast milk given to preterm babies with the B complex vitamins.     

The impact of gestational length on human milk selenium concentration and glutathione peroxidase activity

Longitudinal changes in selenium (Se) and protein concentrations and glutathione peroxidase (GSH-Px) activity of milk collected from healthy mothers of term (n = 12), preterm (n = 10), and very preterm (n = 12) infants were assessed. All infants were size appropriate for gestational age. Milk samples representative of colostrum (d 3), transitional (d 7), and mature milk (d 21 and 42) were assayed. The content of Se in the colostrum secreted by mothers of preterm infants was significantly greater than the Se content of milk secreted by the same mothers at d 21 and 42 of lactation. Mothers of term and very preterm infants, however, produced colostrum with significantly higher levels of Se than milk produced at d 7 (p less than 0.05), d 21 (p less than 0.01), or d 42 (p less than 0.001). Significant differences between the protein concentrations measured in early lactation and in late lactation were evident in all maternal groups. Protein content did not differ significantly among groups at anytime during lactation. An age-related difference was detected in milk GSH-Px activities of mature milk (d 21). Mature milk produced by mothers of very preterm infants on d 21 of lactation contained significantly greater enzyme activity (p less than 0.05) than milk produced by mothers of term infants at the same stage of lactation. Activity of GSH-Px in milk from mothers of very preterm and preterm infants paralleled previously noted changes in long-chain polyunsaturated fatty acid content in human milk with the progression of lactation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vitamin E in human milk from mothers of preterm and term infants

The content of vitamin E (alpha- and beta + gamma-tocopherol) was analyzed in 63 human milk samples obtained from 13 mothers of preterm infants ("preterm" milk) and in 59 milk samples obtained from nine mothers of full-term infants ("term" milk). The changing pattern of the alpha- and beta + gamma-tocopherol content during the course of lactation was identical for both groups. Total vitamin E, alpha- as well as beta + gamma-tocopherol, decreased during the first 2 weeks of lactation and remained constant thereafter. The ratio of alpha- to beta + gamma-tocopherol decreased from about 10:1 to 4:1. At days 3 and 36 of lactation, vitamin E contents (median values and ranges) expressed as milligrams alpha-tocopherol equivalent per 100 ml were 1.45 (0.64-6.4) and 0.29 (0.17-0.48), respectively, for preterm and 1.14 (0.63-4.21) and 0.28 (0.19-0.86), respectively, for term human milk. The vitamin E, alpha-tocopherol and beta + gamma-tocopherol content of preterm human milk did not differ significantly (p less than or equal to 0.05) from that of term human milk at each sampling day. Based on these findings we conclude that the increased requirement of prematures for vitamin E is not reflected in the vitamin E content of milk from mothers delivering preterm infants.     

Human milk: Relationship of fat content with gestational age

In order to assess the suitability of early human milk as a food for preterm infants, concentrations of fat were analyzed in milk samples representative of complete 24-h expressions, obtained serially over the first 30 days of lactation from 47 mothers delivering at term (FT) and 25 mothers delivering prematurely (PT).During the first postpartum month milk fat increased with progressing lactation both in FT and PT mothers' group. The increase was significant over the first 10 day period. During this stage the fat content was significantly higher in the milk from PT mothers than in FT mothers. A significant inverse correlation of fat content with gestational age was established.On the basis of these results, the higher energy intake obtained with PT milk suggests that it may be reasonable to prefer the use of mothers' own early milk than pooled milk as the more appropriate feeding for premature infants.     

Milk protein quality in mothers delivering prematurely: implications for infants in the intensive care unit nursery setting

Because reports comparing the nitrogen content of breast milk from mothers delivering prematurely and at term have conflicted, the present study sought to compare these milks during the first month of lactation with respect to total protein and the distribution of protein among individual protein species and amino acids. No significant differences in total protein concentration were established. However, immunoglobulin comprised a greater proportion of protein in preterm milk than in term milk. The major component of the milk casein fraction, beta-casein, was present in similar proportions in early term and preterm milk, yet increased with time in term milk but not preterm milk. Lactoferrin and lactalbumin were similar in both milks. Differences in amino acid composition were found for serine, arginine, and tyrosine. With respect to protein composition, preterm milk and term milk thus differ during the first month of lactation, and the different patterns of change in individual components suggest that factors other than milk volume contribute to protein content.     

Consequences of the composition of breast milk for the nutrition of underweight newborn infants. II. Lipids and lactose

The concentrations of fat, lactose and protein were measured in the 24 hour pooled breast milk of 37 mothers delivering preterm (PTM) and of 19 mothers delivering term (TM) from the second to the eighth postnatal day and in addition in the PTM from the third week of lactation. During the 4th week of life the nitrogen retention, the fat absorption rate as well as the energy balance were estimated in 21 very low birth weight infants appropriate for gestational age fed either native PTM (n = 11) or by heating procedures sterilized PTM (n = 10). The concentrations of fat and lactose increase within in the first week of lactation. The concentrations of fat are higher in the PTM during the first 3 days of lactation which results in a higher energy density of PTM during the first days of lactation. At the end of the first week of lactation there are no differences in the energy density between PTM and TM. The fat absorption rate was significantly lower in the infants fed sterilized PTM than in the infants fed native PTM (70.5 +/- 8.4 vs 86.3 +/- 7.4 p.c.). Thus, an energy intake of (70.5 to 8.4 vs 86.3 +/- 7.4 p.c.). Thus, an energy intake of 120-130 kcal/kg.d or an energy absorption of more than 100 kcal/kg.d; respectively, is possible by feeding native PTM as well as TM when feeding volumes of more than 180 ml/kg.d are tolerated. When sterilized breast milk is used or the feeding volume is below 160 ml/kg.d an energy supplementation of the milk is necessary.(ABSTRACT TRUNCATED AT 250 WORDS)     

Carnitine concentrations in the milk of different species and infant formulas

Carnitine concentrations were measured in the milk of sheep, cows, goats, and horses, in human milk of term and preterm infants and in European infant formulas. There were significant species' differences in carnitine milk content. Acylcarnitine concentrations ranged from 13 to 47% of total carnitine. This may be related to differences in maternal and/or mammary gland metabolism. The concentration of long-chain acylcarnitine in milk was under 1% in all investigated species. In cow's milk, there was a decrease in acylcarnitine concentration during the first 2 months of lactation. In human milk, carnitine concentrations did not change during the 1st month postpartum, but maternal plasma carnitine concentrations increased and plasma concentrations of acylcarnitine were always lower than those in simultaneously sampled milk. Milk carnitine concentrations in mothers of premature infants were not different from those in mothers of term infants. European formulas based on cow's milk contained somewhat more carnitine than human milk. However, very low carnitine concentrations were found in soy-based or protein hydrolysate formulas. This may lead to nutritional carnitine deficiency in infants receiving these formulas without carnitine supplementation.     

Increased epidermal growth factor levels in human milk of mothers with extremely premature infants

Maternal milk is the major source of nutrients and growth-promoting substances in the first weeks of life for the majority of neonates. Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) are trophic peptides present in human milk with significant healing effects on injured gastrointestinal mucosa. Decreasing gestational age of neonates is associated with higher risk of developing gastrointestinal disorders, and human milk provides better protection against these diseases compared with formula. The aim of this study was to evaluate the concentrations of EGF and TGF-alpha in human milk collected from mothers with infants born: extremely preterm, preterm, and full term. Milk samples were collected at the end of first, second, and fourth week postpartum from each mother of infants born in one of the three gestational age groups: extremely preterm (23-27 wk, n = 16), preterm (32-36 wk, n = 16), and full term (38-42 wk, n = 15). Milk concentrations of EGF and TGF-alpha were quantified with a homologous RIA in the milk aqueous fraction. Concentrations of EGF in human milk from the extremely preterm group (23-27 wk) were significantly higher compared with values from the preterm and full-term groups throughout the first month of lactation. A similar pattern was observed with human milk TGF-alpha; however, milk TGF-alpha levels were lower than EGF. In conclusion, we have found higher concentrations of EGF and TGF-alpha in human milk of mothers with extremely preterm babies. These data may indicate the potential importance of milk-borne EGF and TGF-alpha for the development of extremely premature infants.     

Protein, lactose and fat concentration of breast milk of mothers of term and premature neonates

The protein, lactose and fat concentrations in the milk of seven mothers giving birth at term and six mothers giving birth prematurely were determined. Samples were obtained during the first 31 days of lactation. The protein, lactose and fat concentrations of preterm milk were found to be similar to those of fullterm milk over this period. For both term and preterm groups, protein concentration decreased with increasing age, while lactose concentration increased. Fat concentration did not show a consistent pattern of change in the preterm group, but tended to increase with advancing age in the term group.     

Protein, lactose and fat concentration of breast milk of mothers of term and premature neonates

The protein, lactose and fat concentrations in the milk of seven mothers giving birth at term and six mothers giving birth prematurely were determined. Samples were obtained during the first 31 days of lactation. The protein, lactose and fat concentrations of preterm milk were found to be similar to those of fullterm milk over this period. For both term and preterm groups, protein concentration decreased with increasing age, while lactose concentration increased. Fat concentration did not show a consistent pattern of change in the preterm group, but tended to increase with advancing age in the term group.     

Epidermal growth factor in human milk: daily production and diurnal variation during early lactation in mothers delivering at term and at premature gestation

Epidermal growth factor is a polypeptide that stimulates proliferation and differentiation of a variety of cell types, including the developing intestinal epithelium; it is the agent in human milk that induces mitosis in human fibroblast culture. We systematically evaluated the EGF content of milk from 20 women delivering prematurely and from 11 women delivering at term. In preterm mothers, the concentration of EGF was 70 +/- 5 ng/ml (mean +/- SEM), with no significant change during seven weeks of lactation. EGF concentration in milk of term mothers was 68 +/- 19 ng/ml (mean +/- SEM). No diurnal variation in the concentration was found. Total EGF content was closely correlated with the volume of milk expressed, suggesting a passive transport from the circulation. These observations confirm that a substantial amount of EGF is present in human milk and that EGF concentrations are not affected by duration of gestation, time of day, or duration of lactation.     

Leptin determination in colostrum and early human milk from mothers of preterm and term infants

Background

Leptin is involved in the regulation of food intake and energy expenditure and is therefore important for growth and brain development. Analytical methods used for leptin measurement in human milk differ widely in the literature and yield varying results.

Aims

To compare different preparation methods for the analysis of leptin in human milk and to investigate the leptin levels in colostrum and mature human milk from mothers of preterm or term infants.

Methods

Mothers delivering a preterm (n = 37) or a term infant (n = 40) were recruited for a prospective study and were ask to collect breast milk on the 3rd and 28th day of lactation. Leptin, protein and fat concentrations were analysed. Clinical data of mother and child were recorded prospectively.

Results

Skim milk was most appropriate for leptin analysis. Human milk leptin concentrations did not differ between preterm and term human milk. In term milk, leptin concentration on day 28 was lower than on day 3 (p < 0.05). Milk leptin levels on the 3rd and 28th day were positively correlated with mothers' body mass index, but not with fat content in milk.

Conclusion

Skim milk was the most stabile preparation for leptin analysis. Preterm and term human milk contain leptin in equal concentrations. Human milk leptin depends on mothers' body mass index.     

Low breast milk phosphorus concentration in familial hypophosphatemia

We report breast milk mineral concentrations in a mother with familial hypophosphatemia that was untreated due to poor compliance with medical advice. Milk phosphorus content was extremely low despite normal maternal serum phosphorus concentrations. Milk calcium concentrations were only modestly decreased so that the ratio of calcium to phosphorus was greatly elevated. It appears that mothers with this disorder who breast feed should have their milk mineral content carefully monitored during lactation. If milk mineral content is abnormal despite maternal therapy with phosphorus and vitamin D, infants may require supplementation of mineral intake.     

Concentrations and total daily output of micronutrients in breast milk of mothers delivering preterm: a longitudinal study

The number of preterm infants fed their own mother's milk appears to be increasing as a result of information suggesting certain benefits over milk from human milk banks or proprietary formulas. It is also apparent that the nutritional requirements of term and preterm infants differ. Thus, the finding of various deficiencies in small preterm infants indicates that studies which examine the nutrient content of milk from mothers who deliver prematurely are important to aid in suggesting appropriate supplementation. In order to provide appropriate recommendations, nutrient content must be assayed during the period of exclusive milk feedings. Accordingly, the concentrations and total daily output of breast milk zinc and copper, and vitamins A, C, and E, were examined in a group of 13 mothers delivering at or before 32 weeks gestation. Collections of a total 24-h output were obtained every 7 days for the first 7 weeks after delivery. Concentrations of all micronutrients were similar to those reported previously during the first 5 weeks of lactation. Most striking, however, was the progressive decline in total output as well as concentration of zinc. After the first 2 weeks of lactation, levels of copper and vitamins A, C, and E were not affected by the duration of lactation. There was substantial variation between mothers in daily output of all the micronutrients. The low output of these micronutrients suggests that some attempt should be made at monitoring the mineral and vitamin status of small preterm infants fed exclusively human milk for the first 3 months of life.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anti-endotoxin antibodies in human milk: correlation with infection of the newborn

A longitudinal study was performed to investigate the content of human colostrum and milk of antibodies against endotoxins of Escherichia coli, Pseudomonas aeruginosa and Salmonella minnesota during the first 6 mo of lactation. The influence of the gestational age of the newborn and the prevalence of a systemic infection in the child on maternal antibody production were observed. Colostrum of mothers of term infants who had shown signs of systemic infection contained higher antibody concentrations compared to colostrum of mothers of healthy newborns. After the first week post partum, no difference in the milk's antibody content could be observed between these two groups. Antibody titres rose from 2 wk to 6 mo post partum (p < 0.001). Milk of mothers of preterm infants with signs of systemic infection contained higher antibody titres than milk of mothers of preterm infants without infection throughout the observation period. This difference reached statistical significance 3 wk after delivery (p < 0.05). The corrected endotoxin antibody levels against all tested antigens in milk of mothers of preterm infants with infection 6 mo post partum were 6+/-3.5 times as high as 2 wk post partum. CONCLUSIONS: Breast milk contains anti-endotoxin antibodies. The particularly high levels of antiendotoxin antibodies in cases of neonatal infection may present a special maternal protection for premature infants.     

Cellular composition including lymphocyte subsets in preterm and full term human colostrum and milk.

The cellular composition of colostrum (within 72 hours post partum) and mature milk samples (5th-7th day post partum) from 20 mothers delivering preterm babies and 20 mothers delivering full term babies was examined. Lymphocyte subsets including T cells, B cells, T4 and T8 cells were quantitated by indirect immunoperoxidase staining using specific monoclonal antibodies. The mean total cell count in preterm colostrum (9,338/mm3) was significantly higher than in full term colostrum (5,594/mm3). Similarly, counts for macrophages, neutrophils and lymphocytes were significantly higher in preterm colostrum and milk as compared to full term colostrum and milk. B and T lymphocytes including T4 and T8 cells were identified in both preterm and full term breast milk. The absolute count of T, B, T4 and T8 cells was significantly higher in preterm colostrum compared to term colostrum, though the relative percentage distribution of lymphocyte subsets showed no significant difference between the two groups. T and B cells constituted about 74% and 26% of total lymphocytes, respectively in preterm as well as full term colostrum and about 69% and 31% in preterm and full term milk. The mean T4/T8 ratio was higher in preterm colostrum than term colostrum, being 1.82 and 1.60 respectively. However, this difference was not significant statistically and did not change statistically in the milk sample.     

Consequences of the composition of human milk for the nutrition of low-birth-weight neonates. III. Sodium and potassium

The concentrations of sodium and potassium were studied in the 24 hour pooled human milk of 37 mothers delivered preterm (PTM) and of 19 mothers delivered at term (TM) from the second to the eighth postnatal day and in addition in the PTM during the third week of lactation. During the 4th week of life the sodium balance was estimated in 31 very low birth weight infants fed a human milk formula enriched with NaCl (n = 11) or NaH2PO4 (n = 11) and in 9 infants fed the same formula without supplementary sodium. The concentrations of sodium decrease significantly during the first week of lactation. The values are significantly higher in PTM than in TM during the first 3 days but decrease in both milks to values between 1 and 2 mmol/100 ml. The concentrations of potassium increase up to the 4th day of lactation and fall to approximately 1.5 mmol/100 ml at the end of the first week of lactation. There are no differences between PTM and TM. In all three balance groups the sodium balance are positive. But only in the infants fed a sodium-supplemented human milk formula the weight gain was adequate according to the protein and caloric intakes. No signs of a pathological sodium retention could be observed during the balance period. The data suggest that a sodium intake of more than 2.5 mmol/kg/day is necessary for optimal growth. Thus, the phosphorus supplementation should be done generally as 1 mmol NaH2PO4/100 ml human milk in very low birth weight infants.     

Long‐chain polyunsaturated fatty acids decline rapidly in milk from mothers delivering extremely preterm indicating the need for supplementation

Aim

Our aim was to perform an in‐depth analysis of the composition of fatty acids in milk from mothers delivering extremely preterm babies. We investigated longitudinal changes in milk fatty acid profiles and the relationship between several types of fatty acids, including omega‐3 and omega‐6.

Methods

Milk samples were collected at three stages of lactation from 78 mothers who delivered at less than 28 weeks of pregnancy at the Sahlgrenska University Hospital, Gothenburg, Sweden, from April 2013 to September 2015. Fatty acid composition was analysed by gas chromatography–mass spectrometry.

Results

A reduction in long‐chain polyunsaturated fatty acids (LCPUFAs) was observed during the lactation period. The concentrations of arachidonic acid and docosahexaenoic acid declined from medians of 0.34 to 0.22 mol% and 0.29 to 0.15 mol%, respectively, between postnatal day 7 and a postmenstrual age of 40 weeks. Strong correlations were found between the intermediates of several classes of fatty acids, including omega‐3, omega‐6 and omega‐9.

Conclusion

A rapid reduction in LCPUFA content in the mother's milk during the lactation period emphasises the importance of fatty acid supplementation to infants born extremely preterm, at least during the period corresponding to the third trimester, when rapid development of the brain and adipose tissue requires high levels of LCPUFAs.     

Concentrations of IL-10 in preterm human milk and in milk from mothers of infants with necrotizing enterocolitis

BACKGROUND: Despite the protective effects of human milk against necrotizing enterocolitis, the incidence is highest in the extremely premature infant, and only minimally decreased with feeding human milk. This suggests that certain protective agents may be lower in milk from mothers delivering extremely premature infants. The anti-inflammatory cytokine IL-10 was one possibility. AIM: We hypothesized that low concentrations of IL-10 in preterm milk contribute to the development of necrotizing enterocolitis in extremely premature infants. METHODS: IL-10 in human milk collected at weeks 1, 2, and 4 postpartum was measured by ELISA in mothers of infants born extremely premature at 23-27 wk gestation (group EP), premature at 32-36 wk gestation (group P), and term at 38-42 wk gestation (group T). Single milk samples were collected from a separate group of mothers whose infants developed necrotizing enterocolitis. RESULTS: There were no significant differences in concentrations of milk IL-10 among groups EP, P, or T. Concentrations of IL-10 declined as lactation progressed (p < 0.001). IL-10 in milk was frequently undetected in all groups, but even more so in the milk of the group of women whose infants had necrotizing enterocolitis (86%) than in groups EP (40%) and P (27%) (p < 0.01). CONCLUSION: IL-10 was present in preterm milk from most women, and the concentrations in preterm and term milk were not significantly different. A paucity of IL-10 in human milk was found in certain mothers in each group, especially in those whose infants developed necrotizing enterocolitis.