Effect of storage on breast milk antioxidant activity

How does bovine milk-based fortification alter the oxidant-antioxidant profile of breast milk in preterm infants?

OBJECTIVES

Fortification of breast milk (BM) is recommended to enhance protein, vitamin, and mineral content, supporting improved growth in preterm infants. However, the impact of fortification on the oxidant-antioxidant balance in BM has not been previously studied. This study aims to evaluate the effects of fortification with a bovine milk-based fortifier on the total antioxidant capacity (TAC) and total oxidant status (TOS) in preterm BM.

METHODS

In this prospective cohort study, transitional milk (TM) (6-10 days postpartum) and mature milk (MM) (>15 days postpartum) samples were collected from mothers of preterm infants receiving fortified BM. TAC and TOS were measured in BM samples before and after fortification. The oxidative stress index (OSI), defined as the TOS-to-TAC ratio, was used to assess oxidative stress levels.

RESULTS

Seventy-five BM samples from 59 preterm infants, with a mean gestational age of 31.4 ± 2.8 weeks, were analyzed. TAC levels were consistent between TM and MM of the preterm infants. TOS levels and OSI were lower in TM compared to MM (p = 0.019 and p = 0.033, respectively). Fortification led to increased TAC and TOS in both TM (p < 0.001 each) and MM (p < 0.001 each). The OSI was higher in fortified TM (p = 0.032) compared to unfortified TM, while OSI remained unchanged in fortified MM (p = 0.39).

CONCLUSIONS

Preterm TM exhibits a more favorable oxidant-antioxidant profile compared to MM. Fortification elevates both TAC and TOS in preterm BM. In MM, the oxidant-antioxidant balance is maintained post-fortification; however, in TM, the increase in TOS exceeds that of TAC, resulting in a higher OSI.

Feeding Expressed Breast Milk Alters the Microbial Network of Breast Milk and Increases Breast Milk Microbiome Diversity over Time

Breastfeeding supplies nutrition, immunity, and hormonal cues to infants. Feeding expressed breast milk may result in de-phased milk production and feeding times, which distort the real-time circadian cues carried by breast milk. We hypothesized that providing expressed breast milk alters the microbiotas of both breast milk and the infant's gut. To test this hypothesis, we analyzed the microbiota of serial breast milk and infant fecal samples obtained from 14 mother-infant dyads who were lactating, half of which were providing expressed breast milk. Infant fecal microbiota showed lower α-diversity than breast milk microbiota. Bacterial amplicon sequence variant sharing occurred between breast milk and infant feces with no feeding group differences. However, the age-dependent gain in breast milk α-diversity was only significant in the expressed breast milk group and not in the direct breastfeeding group, suggesting that decreased contact with the infant's mouth influences the milk microbiota. Trending lower connectivity was also noted with breast milk microbes in the direct breastfeeding group, consistent with regular perturbations of the developing baby's oral microbiota by latching on the breast. The results of this preliminary study urge further research to independently confirm the effects of providing expressed breast milk and their health significance.

Predictors of Direct Breastfeeding in Preterm Infants

Objective: Rates of mother's own milk (MOM) provision in the neonatal intensive care unit (NICU) vary widely, despite acceptance as the gold standard for nutrition in preterm infants. Direct breastfeeding (DBF) supports long-term provision of MOM, but factors that support DBF in preterm infants are unknown. The purpose of this study was to identify factors that predict DBF at oral feeding initiation and at NICU discharge. Methods: This was a retrospective cohort study of preterm infants born at ≤ 32 weeks who were receiving MOM at 32 weeks corrected gestational age (cohort 1) and at discharge to home (cohort 2). The primary outcomes were rates of DBF at oral feeding initiation (cohort 1) and at hospital discharge (cohort 2). We examined bivariate associations between infant characteristics, maternal sociodemographic factors, and hospital practices (e.g., lactation visit timing and frequency) with DBF outcomes and then built logistic regression models to determine the adjusted odds ratio and 95% confidence interval ([adjusted odds ratio [aOR] [95%CI]) for independent predictors of the DBF outcomes. Results: Sixty-four percent of eligible infants initiated DBF, and 51% were DBF at discharge. Sociodemographic, NICU, and lactation support factors were associated with both outcomes. Post hoc analysis showed that similar factors also influenced lactation support provision. Conclusions: Lactation support, NICU and sociodemographic variables influence DBF initiation and DBF at discharge. Interventions that optimize efficient use of available lactation support, address bias, and provide ample opportunity for DBF practice could improve rates.

The Effect of Breast Milk from Different Lactation Stages on in Vitro Wound Healing

Objective: Wound healing is a complex and dynamic process essential for restoring tissue integrity and homeostasis. It is thought that breast milk contributes positively to the wound healing process, thanks to the components it contains. The aim of this study is to compare the effects of breast milk on the wound healing process at different lactation stages and to evaluate the underlying mechanism(s). Materials and Methods: The effects of breast milk from different lactation stages (colostrum, transitional, and mature milk) on wound healing were determined by in vitro scratch assay in L929 fibroblast cells. 2,2-Diphenyl-1-picrylhydrazyl (DPPH), total oxidant, and antioxidant capacity were used to confirm antioxidant effects. The effect of breast milk on netrin-1 levels in L929 cells was elucidated by ELISA. Results: Breast milk at different lactation stages promoted wound healing. While the wound closure percentage was determined as 48.7% in the control group, this rate was determined to be the highest at 81.6% in the mature milk group (p:0.0002). The free radical scavenging capacity of colostrum, transitional, and mature milk with DPPH was determined as 49.69%, 60.64%, and 80.85%, respectively, depending on the lactation stages. Netrin-1 levels detected by ELISA were determined as 490.1 ± 6.5 pg/mL in the control group, while the lowest level was determined as 376.6 ± 4.5 pg/mL in mature milk (p:0.0003). Conclusions: Breast milk, especially mature milk, promoted wound healing on L929 cells by suppressing netrin-1 levels and scavenging free radicals.

Longitudinal analysis of carotenoid content in preterm human milk

To describe the variability in carotenoid content of human milk (HM) in mothers of very to extremely low birth weight preterm infants throughout lactation and to explore the relationship between lutein in HM and the occurrence of retinopathy of prematurity (ROP) in preterm infants. We recruited healthy mothers along with their preterm infants that were born at gestational age 24 + 2 to 29 + 6 weeks or with a birth weight under 1500 g and were exclusively breastfed HM. Each participant provided up to 7 HM samples (2-10 ml) on day 0-3 and once a week until 6 weeks. Additionally, when possible, a blood sample was collected from the infant at week 6. Concentrations of the major carotenoids (lutein, zeaxanthin, beta-carotene, and lycopene) in all HM and blood samples were assessed and compared. Thirty-nine mother-infant dyads were included and 184 HM samples and 21 plasma samples were provided. Mean lutein, zeaxanthin, beta-carotene, and lycopene concentration decreased as lactation progressed, being at their highest in colostrum samples (156.9 vs. 66.9 vs. 363.9 vs. 426.8 ng/ml, respectively). Lycopene (41%) and beta-carotene (36%) were the predominant carotenoids in colostrum and up to 2 weeks post-delivery. Inversely, the proportion of lutein and zeaxanthin increased with lactation duration to account for 45% of the carotenoids in mature HM. Lutein accounted for 58% of the carotenoids in infant plasma and only 28% in HM. Lutein content of transition and mature HM did not differ between mothers of ROP and non-ROP infants.Conclusion Carotenoid content of HM was dynamic and varied between mothers and as lactation progressed. Infant plasma displayed a distinct distribution of carotenoids from HM.

The Effects of Different Storage Conditions on Leukocytes in Human Breast Milk

Objectives

Breast milk is the best baby food because it contains various nutrients and important factors for the baby's immune system, including leukocytes. This study aimed to determine the effects on morphology, number of cells and breast milk leukocytes count of various ways of storing breast milk based on different temperatures and storage durations.

Methods

This study was conducted at the Biochemistry Laboratory, Integrated Laboratory and the Histology Laboratory, Universitas Indonesia, Jakarta, Indonesia from September 2022 to February 2023. Transitional breast milk samples from 7 breastfeeding mothers were utilised in the study. A total of 50 mL was divided into 4 tubes of 12.5 mL each and treated based on temperature, storage time and method of thawing frozen breast milk based on the Centers for Disease Control and Prevention's (CDC) recommendations for breast milk storage. The breast milk cells were isolated to calculate the cell number and leukocyte population. Subsequently, the breast milk cells were stained with haematoxylin and eosin to analyse the number and morphology of leukocytes.

Results

The findings showed a significant decrease in the breast milk's total number and population and changes in the morphology of breast milk leukocytes after storage.

Conclusion

This study indicates that CDC storage recommendations do not affect the quantity of the CD45+ leukocyte population; however, there is a decrease in the total number of leukocytes and alterations in their microscopic morphology. Thus, additional research is recommended to determine whether these modifications influence the function of the breast milk cells.

The impact on colostrum oxidative stress, cytokines, and immune cells composition after SARS-CoV-2 infection during pregnancy

Background

Limited data are available regarding the differences between immunological, biochemical, and cellular contents of human colostrum following maternal infection during pregnancy with coronavirus 2 disease (COVID-19).

Objective

To investigate whether maternal COVID-19 infection may affect immunological, biochemical, and cellular contents of human colostrum.

Methods

Using a case-control study design, we collected colostrum from 14 lactating women with a previous diagnosis of COVID-19 during pregnancy and 12 without a clear diagnosis during September 2020 to May 2021. Colostrum samples were analysed for some enzymes and non-enzymatic oxidative stress markers (SOD, CAT, GPx, MDA, GSH, GSSG, H2O2, MPO) and for IL-1β, IL-6, tumour necrosis factor (TNF)-α, protein induced by interferon gamma (IP)-10, IL-8, IFN-λ1, IL12p70, IFN-α2, IFN-λ2/3, granulocyte macrophage colony stimulating factor (GM-CSF), IFN-β, IL-10 and IFN-γ, along with IgA and IgG for the SARS-CoV-2 S protein. We perform immunophenotyping to assess the frequency of different cell types in the colostrum.

Results

Colostrum from the COVID-19 symptomatic group in pregnancy contained reduced levels of H2O2, IFN-α2, and GM-CSF. This group had higher levels of GSH, and both NK cell subtypes CD3-CD56brightCD16-CD27+IFN-γ+ and CD3-CD56dimCD16+CD27- were also increased.

Conclusion

The present results reinforce the protective role of colostrum even in the case of mild SARS-Cov-2 infection, in addition to demonstrating how adaptive the composition of colostrum is after infections. It also supports the recommendation to encourage lactating women to continue breastfeeding after COVID-19 illness.

The Influence of Time and Temperature on Human Milk Storage Antioxidant Properties, Oxidative Stress, and Total Protein

BACKGROUND

Human milk is an essential source of nutrition for an infant's health. When breastfeeding working mothers or students, for example, are unable to breastfeed, storing their milk is recommended. Therefore, it is crucial to know the storage conditions to ensure their antioxidant capacity and avoid oxidative damage.

RESEARCH AIM

To evaluate the stability of the antioxidant and pro-oxidant profiles and the amount of total protein in fresh human milk after different storage times (1, 2, 7, 14, and 21 days) and temperatures (4 ºC and -20 ºC).

METHODS

This was a prospective, longitudinal, and observational study with milk samples grouped according to age for comparisons, which included 20 lactating women. The antioxidant activity was evaluated using the colorimetric methods of free radical scavenging 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid and the decrease of ferric ion. Oxidative stress was determined by the lipid peroxidation product formation through malondialdehyde concentration, and the total protein content was assessed by the Bradford method.

RESULTS

The antioxidant profile of human milk was maintained with minimal losses until the 14^th day when stored at 4 ºC and -20 ºC. The evolution of malondialdehyde concentration over storage revealed significant changes only 21 days after human milk storage at 4 ºC. There was no change in the value of total protein content.

CONCLUSIONS

To sum up, there is no difference in the storage of human milk at a temperature of 4 °C or -20 °C over 14 days. Therefore, the lactating woman may choose the most convenient way of storage.

Methodological approaches for studying the human milk microbiome

Human milk contains a low-biomass, low-diversity microbiome, consisting largely of bacteria. This community is of great research interest in the context of infant health and maternal and mammary health. However, this sample type presents many unique methodological challenges. In particular, there are numerous technical considerations relating to sample collection and storage, DNA extraction and sequencing, viability, and contamination. Failure to properly address these challenges may lead to distortion of bacterial DNA profiles generated from human milk samples, ultimately leading to spurious conclusions. Here, these technical challenges are discussed, and various methodological approaches used to address them are analyzed. Data were collected from studies in which a breadth of methodological approaches were used, and recommendations for robust and reproducible analysis of the human milk microbiome are proposed. Such methods will ensure high-quality data are produced in this field, ultimately supporting better research outcomes for mothers and infants.

Effect of Cold Storage on the Viable and Total Bacterial Populations in Human Milk

Expression and cold storage of human milk is a common practice. Current guidelines for cold storage of expressed milk do not take into account the impact on the milk microbiome. Here, we investigated the impact of cold storage on viable bacterial populations in human milk. Freshly expressed milk samples (n = 10) were collected and analysed immediately, stored at 4 °C for four days, −20 °C for 2.25 months and 6 months, and −80 °C for 6 months. Samples were analysed using propidium monoazide (PMA; a cell viability dye) coupled with full-length 16S rRNA gene. An aliquot of each sample was additionally analysed without PMA to assess the impact of cold storage on the total DNA profile of human milk. Cold storage significantly altered the composition of both the viable microbiome and total bacterial DNA profile, with differences in the relative abundance of several OTUs observed across each storage condition. However, cold storage did not affect the richness nor diversity of the samples (PERMANOVA all p > 0.2). Storage of human milk under typical and recommended conditions results in alterations to the profile of viable bacteria, with potential implications for infant gut colonisation and infant health.

Effect of Purple Corn Anthocyanin on Antioxidant Activity, Volatile Compound and Sensory Property in Milk During Storage and Light Prevention

The aim of this study was to observe the effect of purple corn anthocyanin on the light-induced antioxidant activity, free radicals, volatile compounds, color parameters, and sensory properties of milk during storage. There were four groups: (1) negative control, no addition of anthocyanins + exposure to fluorescent light (NC); (2) positive control 1, no addition of anthocyanins + protected from fluorescent light (PC1); (3) positive control 2, the addition of 0.3% (w/v) anthocyanins + exposure to fluorescent light (PC2); and (4) the addition of 0.3% anthocyanins + protected from fluorescent light (AC). The results indicated that the concentration of antioxidant activity parameters in the NC group decreased during the entire storage period, whereas antioxidant activity parameters were unchanged except for the glutathione peroxidase (GSH-Px) in the AC group. Moreover, the NC group showed lower levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and higher levels of superoxide anion and hydrogen peroxide than the other groups after 1 d of storage period. The extent of malondialdehyde accumulation and lipid peroxidation in the control groups were greater than that of the AC group. Twenty-two volatile compounds were determined in milk, which consisted of eight alcohols, three ketones, five aldehydes, two esters, and four hydrocarbons by headspace gas chromatography mass spectrometer analysis. Specifically, individual aldehydes, esters and hydrocarbons in the AC group remained at relatively stable values during storage relative to the other three groups. Stronger positive correlations were detected between several antioxidant activities (superoxide dismutase, GSH-Px) and DPPH scavenging activity as well as total ketones in milk. Adding of anthocyanin did not impact on the color values of L^*, a^* and b^* in light-protected milk during the entire storage period. Some sensory evaluation parameters (flat, garlic/onion/weedy, oxidized-light, oxidized-metal, rancid) in AC group were significantly higher than that of the control group at the end of the period. In conclusion, the current study revealed that the addition of purple corn anthocyanin pigment to light-protected milk had the potential to prevent lipid oxidation, enhance antioxidant activity, maintain volatile compounds and increase the sensory scores.

Prolonged refrigeration does not alter isoprostanes concentration in human milk

BACKGROUND

The Academy of Breastfeeding Medicine published a clinical protocol for Human Milk storage, recommending refrigeration at a temperature of 4 °C up to 4 d as the optimal conditions for the safety and bactericidal capacity of Human Milk. However, few studies were conducted to evaluate the change in milk composition during this type of refrigeration storage.

AIM

To elucidate some uncertainties regarding the Human Milk composition and prolonged cold storage, we have investigated the effects of storage at 4 °C up to 96 h on an important category of oxidative stress markers: the Isoprostanes (F2-isoprostanes, F4-neuroprostanes and F3-isoprostanes).

MATERIAL AND METHOD

The experiment was repeated 3 times to ensure reproducibility of the results. We enrolled 3 donating healthy mothers for each time (total: 9 mothers). Milk was collected with standard extraction methods. Immediately after collection, each Human Milk sample from each mother was pooled and then divided into 5 aliquots. One aliquot (0 h) was immediately frozen at -80 °C until the analysis. The other aliquots (24 h, 48 h, 72 h, 96 h) were stored in a refrigerator at 4 °C respectively for 24, 48, 72 and 96 h, then immediately frozen at -80 °C until the analysis. Milk samples were then used to determine concentration of Isoprostanes in Liquid Chromatography - Mass Spectrometry and Liquid Chromatography - Tandem Mass Spectrometry.

RESULTS

Isoprostanes were detectable in all Human Milk samples. There was no significant trend of the concentration of the tested analytes over time.

DISCUSSION AND CONCLUSION

This study provides evidence of the presence in human milk of all the tested isoprostanes: in particular, F2-isoprostanes, F4-neuroprostanes and F3-isoprostanes. Refrigeration and storage of fresh Human Milk in controlled conditions for 96 h did not significantly affect its bioactivity and nutritional quality related with these biomarkers.

Human Milk for the Term Newborn

Human milk provides optimal nutrition for term newborns, but the prevalence of its use is below target, and risks have been identified. Infants of black mothers as well as term newborns admitted to the neonatal intensive care unit are at risk for not receiving human milk. To improve human milk intake, multiple individual-level interventions have been shown to be effective, but some popular system-level interventions are ineffective or harmful. Expressed milk and donor milk may be less beneficial than direct breastfeeding. Nuanced public policies can help support lactation while promoting individual choice and equity.

Association between expressed breast milk feeding and breastfeeding duration in Hong Kong mothers

BACKGROUND

Expressed breast milk feeding has increased substantially in the past two decades. Once used primarily for preterm infants, feeding expressed breast milk is now more common in mothers giving birth to healthy term infants. However, the effect of expressed breast milk feeding on breastfeeding duration is unclear.

OBJECTIVES

To assess the association between breast milk expression practices and breastfeeding duration in women giving birth to healthy infants.

METHODS

From 2017 to 2018, we recruited 821 new mothers from two public hospitals in Hong Kong. Participants were followed up at 1.5, 3, and 6 months postpartum or until they stopped breastfeeding. The proportion, type, and mode of all milk feeding were assessed at each follow-up.

RESULTS

At 1.5 months postpartum, 47.9%, 37.7%, and 14.4% of participants were feeding by direct breastfeeding only, mixed-mode feeding, and expressed breast milk only, respectively. Participants feeding expressed breast milk only were more likely to be supplementing with infant formula. When compared with participants who provided only direct breastfeeding, participants who gave only expressed breast milk at 1.5 months had 57% lower odds of breastfeeding continuation at three months postpartum. After stratification by infant formula supplementation, expressed breast milk feeding only at 1.5 months was associated with an increased risk of breastfeeding cessation in participants supplementing with infant formula (adjusted hazard ratio [aHR] = 1.86, 95% CI = 1.17-2.95).

CONCLUSION

In the first six months postpartum, giving only expressed breast milk is associated with early breastfeeding cessation, especially in participants who are also supplementing with infant formula.

Is the Antioxidant Capacity of Stored Human Milk Preserved?

Background: In the neonatal intensive care unit (NICU) expressed mothers' milk usually is stored frozen until used. We found that when human milk was stored at -20°C for up to 9 months there were reduced bacterial counts and pH, increased free fatty acids, but unchanged immune proteins. Antioxidant protection is an important benefit of human milk. Few studies have evaluated long-term effects of cold storage on the antioxidant capacity of human milk. We hypothesized that the antioxidant capacity of human milk is affected adversely by long-term storage at -20°C. Objective: To study the impact of long-term cold storage on the oxidative capacity of human milk and the biological impact of these changes on macromolecular constituents of human milk. Methods: Freshly expressed milk was obtained from mothers in the NICU, stored at -20°C for 6 months, and compared with the baseline. Paired samples were analyzed for glutathione, hydrogen peroxide (H₂O₂), 8-isoprostane, catalase, and superoxide dismutase. Results: There was no change in H₂O₂ concentration between baseline and 6 months. Significant reductions from baseline in both catalase and superoxide dismutase concentrations and activities, total glutathione, oxidized glutathione, reduced glutathione, and the ratio of reduced to oxidized glutathione were observed (p < 0.05). There was a significant increase in 8-isoprostane concentrations (p < 0.001). Conclusion: These data indicate significant changes in antioxidant capacity of human milk, including oxidation of macromolecules, after storage at -20°C for 6 months. The clinical implication of these findings may explain the nonuniform protection against oxidant disease in preterm infants fed human milk.

Is Lactoferrin Supplementation Beneficial for All Preterm Infants?

OBJECTIVE

 Human milk (HM) has antibacterial properties due to the presence of immune-modulators, including lactoferrin (LF). This study will determine effect(s) of HM maturation, fortification, and storage conditions on LF levels and its antibacterial properties.

STUDY DESIGN

 HM samples (n = 30) were obtained from preterm and term mothers. The LF levels were analyzed by ELISA, and the antibacterial activity was measured after inoculation with Escherichia coli.

RESULTS

 The highest level of LF in preterm HM was observed in the first week of lactation. However, storage of preterm HM at 4°C decreased LF levels significantly. Both LF levels and antibacterial activity in preterm HM was lower compared with term HM, but significantly higher than donor HM even after HM-based fortification. LF supplementation of donor HM improved its antibacterial activity.

CONCLUSION

 Preterm infants fed donor HM, formula, or stored HM at 4°C may benefits from LF supplementation to improve HM antibacterial properties.

KEY POINTS

· Milk LF levels vary with storage and maturity.. · Donor milk is deficient in LF even after adding HM-based fortification.. · Donor HM and formula fed infants may benefit from LF..

Effect of microorganisms on the fingerprint of the volatile compounds in pine nut (Pinus koraiensis) peptide powder during storage

Pine nut (Pinus koraiensis) peptide (PNP) powder possesses promising bioactivities. However, the powder may have the quality problem of becoming sticky and smelly. Therefore, the volatile compounds' fingerprint of PNP powder was established by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The essential spoilage microorganisms were confirmed by 16S rDNA amplicon sequencing. The antioxidant activity, which presents PNP powder's quality, decreased during storage with the highest value of (1.88 ± 0.18) × 10¹⁴ at day 30. Fifty-nine significantly changed signals were detected; eight compounds were considered as volatile marker compounds. Besides, Firmicutes and Cyanobacteria were the essential spoilage microorganisms in PNP powder at the phylum level. Significantly, unidentified_Chloroplast, which belongs to Cyanobacteria, had a positive correlation with volatile marker compounds. The results proved that microorganisms indeed affect volatile compounds of PNP powder and induced off-flavor, including hexanal, which can be used as the detection indicator for the quality control of PNP powder. PRACTICAL APPLICATIONS: In the present study, we controlled the influence of moisture migration on PNP powder and investigated microorganisms' effects on volatile compounds of PNP powder. HS-GC-IMS could be used to establish fingerprints of volatile compounds in PNP powder. 16S rDNA amplicon sequencing method could be used to screen the dominant spoilage bacteria in PNP powder and established essential spoilage microorganisms of PNP powder. This work provides a reference for category identification of PNP powder, which was infected by spoilage bacteria or not, and stored at day 0 or 30 days. Hexanal can be considered as the volatile marker compound generated from microorganisms. It helps to realize the controllability of PNP powder storage and prolongs the shelf life of PNP powder.

Evaluation of Total Antioxidant Capacity and Total Oxidant Status of Preterm and Term Breast Milk during the Course of Lactation and within a Nursing Session

OBJECTIVE

Breast milk (BM) contains antioxidant molecules which may offer protection against oxidative stress (OS). We aim to investigate oxidant-antioxidant balance in preterm BM during the course of lactation and within a nursing session.

STUDY DESIGN

Total antioxidant capacity (TAC) and total oxidant status (TOS) were measured in colostrum, transitional, and mature BM samples of preterm infants born earlier than 34th week of pregnancy and healthy term infants. Oxidative stress index (OSI) was calculated. Foremilk and hindmilk samples were collected separately.

RESULTS

In colostrum and transitional milk, TAC (p < 0.001 and p = 0.001, respectively) and TOS (p = 0.005 and p < 0.001, respectively) were lower in preterm BM compared with term BM. OSI was also lower in preterm BM, but it was statistically significant only in transitional milk (p < 0.001). TAC was highest in colostrum and decreased through the course of lactation. However, the decrease in TAC was not statistically significant in preterm BM. Lowest values of TOS and OSI were observed in colostrum. In transitional term BM, hindmilk had a better oxidant-antioxidant profile as indicated by lower TOS and OSI.

CONCLUSION

Oxidant-antioxidant balance is preserved in BM in every stage of lactation. Preterm BM has lower OSI which may offer benefits to preterm newborn against OS.

Study of the phenolic compound profile and antioxidant activity of human milk from Spanish women at different stages of lactation: A comparison with infant formulas

Human milk (HM) has been proven to have important and essential antioxidant properties to counteract infant susceptibility to oxidative stress. Phenolic compounds are secondary metabolites which come from plants and are potent natural antioxidants. The ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method used in the present study allowed the quantification of 26 phenolic compounds (ten hydroxybenzoic acids, seven hydroxycinnamic acids, four flavonoids, three hydroxybenzaldehydes and two other polyphenols) in HM samples at different stages of lactation (colostrum, transitional milk and mature milk) and infant formulas (IF). Many of the phenolic compounds identified have been reported to be present in HM for the first time. The total phenolic compound content (TPC) was quantified using the Folin assay and the antioxidant activity (AC) was evaluated with the DPPH, ABTS and FRAP assays. Significant differences were evidenced between HM and IF. HM from mothers with an adherence to a Mediterranean diet contained twice as many individual phenolic compounds as infant formulas, with a higher proportion of hydroxybenzoic acids. Conversely, IF showed a higher proportion of hydroxycinnamic acids. Overall, the antioxidant activity of HM showed small variations during lactation.

Best Practices for Human Milk Collection for COVID-19 Research

In addition to providing life-giving nutrients and other substances to the breastfed infant, human milk can also represent a vehicle of pathogen transfer. As such, when an infectious disease outbreak, epidemic, or pandemic occurs-particularly when it is associated with a novel pathogen-the question will naturally arise as to whether the pathogen can be transmitted through breastfeeding. Until high-quality data are generated to answer this question, abandonment of breastfeeding due to uncertainty can result. The COVID-19 pandemic, which was in full swing at the time this document was written, is an excellent example of this scenario. During these times of uncertainty, it is critical for investigators conducting research to assess the possible transmission of pathogens through milk, whether by transfer through the mammary gland or contamination from respiratory droplets, skin, breast pumps, and milk containers, and/or close contact between mother and infant. To promote the most rigorous science, it is critical to outline optimal methods for milk collection, handling, storage, and analysis in these situations, and investigators should openly share their methods in published materials. Otherwise, the risks of inconsistent test results from preanalytical and analytical variation, false positives, and false negatives are unacceptably high and the ability to provide public health guidance poor. In this study, we provide "best practices" for collecting human milk samples for COVID-19 research with the intention that this will also be a useful guide for future pandemics.

Delays in processing and storage of pig seminal plasma alters levels of contained antioxidants

Seminal plasma (SP) antioxidants are considered biomarkers of sperm function and fertility for AI-boars. The current protocol for their measurement implies the SP was harvested immediately after ejaculation and prompt stored at -80 °C until analysis. Such protocol may be impractical for AI-centers. This study evaluated how SP levels of antioxidants were influenced by delays in (1) SP-harvesting (0 [control], 2 or 24 h at 17 °C after ejaculate collection), in (2) SP-freezing (0 [control] or 24 h at 17 °C after SP-harvesting) or (3) the temperature of storage (-80 °C [control] or - 20 °C). The SP-antioxidants evaluated were: glutathione peroxidase [GPx], superoxide dismutase [SOD], paraoxonase-1 [PON-1], trolox equivalent antioxidant capacity [TEAC] and oxidative stress index [OSI]. A total of 120 aliquots from 10 entire ejaculates were handled in three trials. They were centrifuged (1500 g, 10 min) for harvesting SP and antioxidants were measured with an Automatic Chemistry Analyzer. A 24 h-delay in harvesting the SP led to an increase (p˂0.001) in TEAC and SOD SP-levels, and a decrease (p˂0.05) of OSI and PON-1. Similarly, a 24 h-delay to freeze the SP increased (p˂0.01) TEAC values and decreased (p˂0.01) PON-1 and GPx activity levels. Finally, storing the SP at -20 °C decreased (p˂0.001) SP-levels of TEAC, PON-1 and GPx, and increased (p˂0.01) OSI values. Strong positive relationships (p˂0.001) were found between antioxidant SP-levels in processed samples and their respective controls. In sum, handling and SP storage influence antioxidant measurements in AI-boars. Reliable levels of SP-antioxidants can only be warranted if a strict protocol for harvesting and SP storage is followed.

Pituitary Glycoprotein Hormones in Human Milk before and after Pasteurization or Refrigeration

Our aims were to investigate the presence of pituitary glycoprotein hormones in preterm and donor milk, and to examine the effects of Holder pasteurization and refrigeration on the levels of these hormones. We measured follicle-stimulating hormone (FSH), luteinizing hormone (LH), and thyroid-stimulating hormone (TSH) in milk samples from mothers who delivered prematurely (n = 27) and in samples of mothers who delivered at term and donated milk to the Mother's Milk Bank of Iowa (n = 30). The gonadotropins and TSH were present in similar amounts within human milk produced for preterm and term infants. FSH increased 21% after refrigeration (p < 0.05), while LH declined by 39% (p < 0.05). Holder pasteurization decreased LH by 24% (p < 0.05) and increased TSH by 17% (p < 0.05). Holder pasteurization followed by refrigeration resulted in a 21% increase in FSH and a 41% decrease in LH (both p < 0.05), resulting in more than a 3-fold increase in donor milk FSH:LH ratios (p < 0.05 versus fresh donor milk). Despite structural similarities, the gonadotropins are differentially impacted by Holder pasteurization and refrigeration, and this results in marked alterations in the relative amount of FSH and LH that may be administered to preterm infants, potentially swinging hormonal balance towards ovarian hyperstimulation in females and hypogonadism in males.

Hygienic-sanitary quality and effect of freezing time and temperature on total antioxidant capacity of human milk

Abstract Knowledge of the hygienic-sanitary quality of raw human milk helps to establish the best storage conditions for the preservation of its nutritional and functional components. Therefore, this study aimed to evaluate the hygienic-sanitary quality of human milk extracted at the mothers’ homes, and to analyze the effect of freezing time and temperature on the milk’s total antioxidant capacity. Milk of five mothers was evaluated individually for Staphylococcus aureus, total aerobic mesophilic counts, mold and yeasts, total and thermotolerant coliforms. The milk pool was stored at -8 °C, -18 °C and -40 °C for 2, 4, 8 and 15 days and analyzed for the total antioxidant capacity by the 2,2-diphenyl-1-picrylhydrazyl free radical and 2,2-azino 3-ethylbenzothiazoline-6-sulfonic acid scavenging methods. The microbiological analyses of the raw human milk samples indicated counts of all the studied microorganisms above the safe limits. Related to the effect of freezing time and temperature on total antioxidant capacity, it was concluded that, regardless of the freezing temperature, a significant reduction occurred on total antioxidant capacity over time and that the lower the storage temperature, the greater its total antioxidant activity.

Differences in Current Procedures for Handling of Expressed Mother's Milk in Danish Neonatal Care Units

BACKGROUND

Mother's own milk (MOM) is preferred when feeding preterm infants. When expressed mother's milk is stored and handled, there is a risk of bacterial contamination, decreased immunological activity, and less nutritional potential.

PURPOSE

The aim of this study was to investigate current routines when handling MOM in Danish neonatal intensive care units (NICUs).

METHODS

A survey was sent to all 17 NICUs in Denmark in which current practices regarding human milk handling, storage, and preparation were evaluated. Furthermore, one question sought to establish when mother's milk was believed to be colostrum. Respondents of the survey were neonatal nurses.

RESULTS

All 17 units responded to the survey. Only 5 of 17 units answered that human colostrum was defined as milk from the first week after birth. Refrigerator storage time varied between 24 and 72 hours. In 6 of 17 units, parents were in charge of mixing milk and fortifier. Heating of human milk was done by using microwave ovens in 4 of 17 of the units.

IMPLICATIONS FOR PRACTICE

This national survey established that there is significant variability in the way mother's milk is handled. Some of the procedures performed may affect the quality of the milk. It is important to implement evidence-based practice regarding storage and handling of expressed mother's milk to ensure that the quality of the milk is the best possible alternative for all preterm infants.

IMPLICATIONS FOR RESEARCH

Prospective studies are needed to examine the association between handling of human milk and changes in composition and nutritional potential of the milk.

The effects of storage conditions on long-chain polyunsaturated fatty acids, lipid mediators, and antioxidants in donor human milk - A review

Donor human milk (DHM) is the recommended alternative, if maternal milk is unavailable. However, current human milk banking practices may negatively affect the nutritional quality of DHM. This review summarises the effects of these practices on polyunsaturated fatty acids, lipid mediators and antioxidants of human milk. Overall, there is considerable variation in the reported effects, and further research is needed, particularly with lipid mediators and antioxidants. However, to preserve nutritional quality, DHM should be protected from light exposure and storage at 4 °C minimised, to prevent decreases in vitamin C and endocannabinoids and increases in free fatty acids and lipid peroxidation products. Storage at -20 °C prior to pasteurisation should also be minimised, to prevent free fatty increases and total fat and endocannabinoid decreases. Storage ≤-70 °C is preferable wherever possible, although post-pasteurisation storage at -20 °C for three months appears safe for free fatty acids, lipid peroxidation products, and total fat content.

Changes to breast milk fatty acid composition during storage, handling and processing: A systematic review

This review evaluated the effect of various storage and handling conditions on the fat composition of expressed breast milk (EBM). Three databases PubMed, Embase and Scopus were searched in April 2019 with words from the three key components: human milk, handling process (i.e. storage and/or pasteurization), and fatty acid composition. The comparisons were EBM subjected to handling processes versus fresh EBM or versus EBM subjected to another handling processes. Both intervention and observational studies were included, and the outcomes measured included total fat and lipid classes of the EBM. We included 42 studies (43 reports), 41 of which were assessed to be of good quality. Relative changes to the fat composition of EBM subjected to handling processes were calculated based on the data provided in the included studies, and the results were synthesized narratively. The total fat content and total fatty acid composition of EBM was not generally influenced by storage and handling process, with most changes less than 10%, which is likely a result of methodological variation. A reduction in EBM triglyceride concentration and concomitant increase in free fatty acid concentration were seen after exposing to various conditions, probably due to endogenous lipase.

Mother's Own Milk and Bronchopulmonary Dysplasia: A Systematic Review and Meta-Analysis

Background: Bronchopulmonary dysplasia (BPD) is the most common complication of very preterm birth and can lead to lifelong health consequences. Optimal nutrition is a cornerstone in the prevention and treatment of BPD. In very preterm infants, mother's own milk (MOM) feeding is associated with lower risks of necrotizing enterocolitis, retinopathy of prematurity, and sepsis. Although several studies have shown that MOM may protect against BPD, a systematic analysis of the evidence has not been performed to date. Methods: A comprehensive literature search was conducted using PubMed/MEDLINE and EMBASE, from their inception to 1 December 2017. Longitudinal studies comparing the incidence of BPD in preterm infants fed with exclusive MOM, MOM supplemented with preterm formula (PF), and/or exclusively fed with PF were selected. A random-effects model was used to calculate the Mantel Haenszel risk ratio (RR) and 95% confidence interval (CI). Results: Fifteen studies met the inclusion criteria (4,984 infants, 1,416 BPD cases). Use of exclusive MOM feedings was associated with a significant reduction in the risk of BPD (RR 0.74, 95% CI 0.57-0.96, 5 studies). In contrast, meta-analysis could not demonstrate a significant effect on BPD risk when infants fed with more than 50% MOM were compared with infants fed with <50% MOM (RR 0.98, 95% CI 0.77-1.23, 10 studies) or when infants fed with MOM supplemented with PF were compared with infants fed with exclusive PF (RR 1.00, 95% CI 0.78-1.27, 6 studies). Meta-regression showed that differences in gestational age were a significant confounder of the effect of MOM. Conclusion: To our knowledge, this is the first systematic review and meta-analysis that specifically evaluates the role of MOM on BPD. Our data indicate that MOM may reduce the incidence of BPD when used as an exclusive diet, but this result needs to be interpreted with caution. We did not find the same difference in analyses with other dosages of MOM. Further studies adequately powered to detect changes in BPD rates and that adjust for confounders are needed to confirm the beneficial effects of MOM on BPD.

Total antioxidant status in fresh and stored human milk from mothers of term and preterm neonates

BACKGROUND

Antioxidant defense of the body is assured by both endogenous and exogenous factors comprising several enzymes, vitamins, protein components and derivates and oligoelements. Breast milk has been proven to have important and essential antioxidant composition to prevent and protect against diseases in infancy. The objective of this study was to determine the total antioxidant status (TAS) of human milk and to evaluate the differences between premature milk and term milk at different moments of lactation (colostrum, transitional milk and mature milk). A second objective was to evaluate how TAS varies whether the human milk is refrigerated or frozen.

METHODS

Pumped human milk samples of the third, seven and 30th day were collected from women who had term deliveries (30 cases) and preterm deliveries (60 cases). Samples were refrigerated (+4 °C) or frozen in domestic conditions (-20 °C) for various durations and TAS was determined using the ABTS® technique with Randox® reagents and compared for the two groups.

RESULTS

Higher values were found in term versus preterm fresh milk at 30 days of lactation. A slight reduction in TAS was found after 72 h of refrigeration, while 1 week freezing produced significant decrease of total antioxidants. Freezing for 12 weeks reduced more than 50% of TAS in fresh milk.

CONCLUSION

Breastfeeding provides the optimal antioxidant for neonates, regardless of gestational age. Fresh milk has the higher antioxidant power. When it is not available, refrigerated milk for 24 h is better than for 72 h and preferable than frozen milk. Freezing human milk for 3 months in household conditions markedly diminishes TAS.

Donor Human Milk: Effects of Storage and Heat Treatment on Oxidative Stress Markers

Mother's own milk is the first choice for the feeding and nutrition of preterm and term newborns. When mother's own milk is unavailable or in short supply donor human milk (DM) could represent a solution. Heat treatment and cold storage are common practices in Human Milk Banks (HMBs). Currently, Holder pasteurization process is the recommended heat treatment in all international guidelines. This method is thought to lead to a good compromise between the microbiological safety and nutritional/biological quality of DM. Moreover, storage of refrigerated milk is a common practice in HMBs and in NICUs. Depending on the length and on the type of storage, human milk may lose some important nutritional and functional properties. The available data on oxidative stress markers confirm that pasteurization and refrigeration affected this important elements to variable degrees, even though it is rather difficult to quantify the level of deterioration. Nonetheless, clinical practice demonstrates that many beneficial properties of human milk are preserved, even after cold storage and heat treatment. Future studies should be focused on the evaluation of new pasteurization techniques, in order to achieve a better compromise between biological quality and safety of DM.

Infant feeding patterns and eczema in children in the first 6 years of life

BACKGROUND

Modes of infant feeding such as direct and indirect breastfeeding, and formula feeding, and their combinations may play a role in child health.

OBJECTIVE

The aim was to investigate which feeding patterns in the first 6 months pose risks of eczema/skin allergy in children up to 6 years compared to direct breastfeeding for at least 3 months.

METHODS

The Infant Feeding Practices Study II in the United States and its 6-year follow-up provided data on feeding modes in infancy and doctor's diagnosed eczema/skin allergy in the first 6 years of life (1387 infants), based on parental reports. Different feeding patterns were identified. Log-linear models were used to estimate prevalence ratios (PRs) of feeding patterns for doctor's diagnosed eczema/skin allergy in the first 6 years of life, adjusting for confounders.

RESULTS

Compared to "direct breastfeeding for at least 3 months" (DBF3m), the combination of "direct feeding at the breast (DBF), pumping and feeding breast milk (BM), and formula (FF) in the first months" (DBF/BM/FF) showed a statistically significant higher risk of eczema/skin allergy in the first 6 years of life (PR = 1.46), adjusting for confounders. DBF combined with BM for the first 3 months followed by mixed feeding also had an increased risk (PR = 1.26), although not statistically significant. Formula feeding introduced since birth had no effect on eczema. Among the confounders, paternal eczema and race/ethnicity (Hispanic vs White) were associated with a higher risk of eczema/skin allergy.

CONCLUSIONS & CLINICAL RELEVANCE

Mixed infant feeding may carry a higher risk of eczema/skin allergy compared to direct feeding at the breast. The recent epidemic of pumping and feeding in the United States and the use of mixed infant feeding modes requires additional studies to provide appropriate and renewed assessments of the risks of feeding modes for the future development of allergies.

The consequence of phototherapy exposure on oxidative stress status of expressed human milk

OBJECTIVE

There exists evidence that phototherapy can disturb the oxidant/antioxidant balance in favor of oxidants. If phototherapy is continued during tube feeding in preterms, expressed human milk is subjected to phototherapy lights for about 20 min per feeding. We aimed to investigate the effects of phototherapy lights on oxidative/antioxidative status of expressed human milk.

STUDY DESIGN

Milk samples of 50 healthy mothers were grouped as control and phototherapy and exposed to 20 min of day-light and phototherapy light, respectively. Total antioxidant capacity (mmol-Trolox equiv/L) and total oxidant status (mmol-H₂O₂/L) in expressed human milk samples were measured.

RESULTS

Levels of antioxidant capacity of the expressed human milks in the phototherapy group were lower than those of the control group [mmol-Trolox equiv/L; median (interquartile-range): 1.30 (0.89-1.65) and 1.77 (1.51-2.06), p: < .001]. Levels of oxidant status were similar in both groups.

CONCLUSION

We demonstrated that phototherapy decreased antioxidant capacity of expressed human milk without any alteration in oxidative status. We think that this observation is important for the care of very low birth weighted infants who have limited antioxidant capacity and are vulnerable to oxidative stress. It may be advisable either to turn off the phototherapy or cover the tube and syringe to preserve antioxidant capacity of human milk during simultaneous tube feeding and phototherapy treatment.

Human milk expression as a sole or ancillary strategy for infant feeding: a qualitative study

In the United States, a significant proportion of human milk (HM) is now fed to infants from bottles. This mode of infant feeding is rarely measured or described in research studies or monitored by national surveillance systems. Consequently, little is known about expressed-HM feeding as an infant feeding strategy. Our objective was to understand how mothers use HM expression and expressed-HM feeding as a sole strategy or in combination with at-the-breast feeding to feed HM to their infants. We conducted semi-structured interviews with 41 mothers with experience of HM expression and infants under three years of age. Data were analysed using a grounded theory approach for sub-themes related to the pre-selected major themes of maternal HM production and infant HM consumption. Within the major theme of maternal HM production, sub-themes related to maternal over-production of HM. Many mothers produced more HM than their infant was consuming and stored it in the freezer. This enabled some infants to consume HM weeks or months after it was expressed. Within the major theme of infant HM consumption, the most salient sub-theme related to HM-feeding strategies. Four basic HM-feeding strategies emerged, ranging from predominant at-the-breast feeding to exclusive expressed-HM feeding. The HM-feeding strategies and trajectories highlighted by this study are complex, and most mothers fed HM both at-the-breast and from a bottle-information that is not collected by the current national breastfeeding survey questions. To understand health outcomes associated with expressed-HM feeding, new terminology may be needed.

Antioxidative Activity of Colostrum and Human Milk: Effects of Pasteurization and Storage

OBJECTIVES

Milk banks collect, pasteurize, and freeze/store human milk. The processing may alter redox properties of milk, but the effects have not been fully examined.

METHODS

We collected 10 mature milk and 10 colostrum samples and applied a battery of biochemical assays and electron paramagnetic resonance spectroscopy to inspect changes that milk undergoes with pasteurization and 30 days storage at -20°C.

RESULTS

Pasteurization and storage of raw milk did not affect total nonenzymatic antioxidative capacity, but specific components and features were altered. Urate radical and ascorbyl radical emerge as products of exposure of milk to hydroxyl radical-generating system. Processing shifted the load of antioxidative activity from ascorbate to urate and lowered the capacity of milk to diminish hydroxyl radical. Pasteurization caused a significant drop in the activity of 2 major antioxidative enzymes-superoxide dismutase and glutathione peroxidase, whereas freezing/storage of raw milk affected only superoxide dismutase. Colostrum showed drastically higher total nonenzymatic antioxidative capacity, hydroxyl radical scavenging ability, and glutathione reductase activity compared with mature milk.

CONCLUSIONS

Pasteurization and storage affect nonenzymatic and enzymatic antioxidative agents in human milk. It appears that nonenzymatic antioxidative systems in colostrum and milk are different. The effects of processing may be partially compensated by fortification/spiking with ascorbate before use.

Comparison of lactoferrin activity in fresh and stored human milk

OBJECTIVE

Lactoferrin (Lf), the dominant protein in human milk (HM), has been shown to have anti-inflammatory and anti-microbial activity in the neonatal gut. Previous studies indicate that freezing significantly decreases the concentration of Lf in HM. The objective of our study was to compare the activity of Lf in fresh and frozen HM over time.

STUDY DESIGN

HM samples were examined fresh and after storage at -20 °C for 3 and 6 months. Lf concentration was determined by enzyme-linked immunoassay, and the activity was measured by examination of nitric oxide (NO) production and tumor necrosis factor-α secretion from rat macrophages exposed to HM samples.

RESULT

After 3 and 6 months at -20 °C, the average decrease in Lf concentrations was 55% and 65%, respectively. The bioactivity of Lf also decreased significantly over 6 months.

CONCLUSION

Freezing HM for 3 or more months significantly decreases Lf levels and activity. Periodically providing fresh HM may benefit vulnerable preterm neonates.

An Evaluation of Oxidative Status in Serum and Breast Milk of Mothers Giving Birth Prematurely and at Full-Term

Background:

Burning fat and carbohydrates to provide energy in biological systems causes the formation of free oxygen species.

Objectives:

This study aimed to evaluate the oxidative status of serum and breast milk of mothers giving birth prematurely and at full-term.

Materials and Methods:

The study comprised 50 mothers who gave birth at full-term at more than 38 weeks and 43 mothers who gave birth pre-term at below 32 weeks. On the postnatal 5th day, samples of the mother’s milk and serum were taken and stored at -80°C until the study day. On the study day, the total oxidant and total antioxidant levels were measured using the Erel method and the oxidative stress index (OSI) was calculated.

Results:

While the total oxidant level and total antioxidant level values of the milk of the premature birth mothers were found to be significantly high compared to those of the full-term birth mothers (P = 0.001), no statistically significant difference was found in the oxidative stress index values (P > 0.05). No statistically significant difference was found in the total oxidant level and oxidative stress index values of the serum of the premature birth mothers compared to those of the full-term birth mothers, while the total antioxidant level was found to be significantly low (P = 0.04).

Conclusions:

The oxidants and antioxidants in the milk of mothers giving birth prematurely were found to be significantly higher than those of full-term birth mothers. This can be evaluated as the milk of the premature birth mothers providing increased antioxidant defense to protect the infant.

Vitamins, fatty acids, and antioxidant capacity stability during storage of freeze-dried human milk

Although freezing is the most common method used to preserve human milk, nutritional and immunological components may be lost during storage. Freeze-drying could increase the shelf life of human milk, while preserving its original characteristics. Seventy-two samples of freeze-dried human milk were stored for different periods of time, up to a maximum of 3 months, at 4 °C or 40 °C. Vitamin C, tocopherols, antioxidant capacity, and fatty acids composition were analyzed. A new HILIC-UHPLC method improving vitamin C determination was also validated. Ascorbic acid and total vitamin C concentrations significantly decreased at both temperatures, while antioxidant capacity only decreased at 40 °C. Fatty acids composition and both γ-tocopherol and δ-tocopherol contents remained unaltered. The stability after storage of freeze-dried milk was higher than that reported for frozen or fresh milk indicating that freeze-drying is a promising option to improve the preservation of human milk in banks.

Storage at -80°C preserves the antioxidant capacity of preterm human milk

BACKGROUND AND OBJECTIVE

It is essential to establish optimum parameters for maintaining the quality of stored milk until the moment of consumption with minimal deterioration of its properties. The aim of the study was to evaluate total antioxidant capacity (TAC) and total oxidation status (TOS) of fresh and freeze-stored samples (at -80°C) of preterm human milk (HM).

METHODS

Samples of colostrum were collected from 98 healthy women within the first 4 days after delivery. The total milk volume collected (6 ml) was divided in two aliquot parts: 3 ml for the fresh analysis which was done immediately after the extraction and 3 ml for storage under freezing conditions at -80°C for three months. The antioxidant status and oxidative stress of the fresh and stored breast milk were assessed via determination of TAC and TOS levels.

RESULTS

The mean gestational age and the birth weight of the infants were 31.26 ± 2.93 weeks and 1620 ± 581.91 g; respectively. There were no significant correlations between maternal age, route of delivery and milk oxidative stress. There was no significant difference between the levels of TAC, TOS and the oxidative stress index in fresh and freeze-stored samples of colostrum in preterm HM (p > 0.05).

CONCLUSION

Freeze storage of preterm HM at -80°C for three months preserves the antioxidant capacity without changing oxidative status of HM, which could be noteworthy for the preterm infant nutrition.

Is variation in total antioxidant capacity of human milk associated with levels of bio-active proteins?

OBJECTIVE

As the antioxidant properties of human milk may be beneficial for very preterm-born infants, it is important to identify the association between total antioxidant capacity (TAC) and bio-active proteins.

STUDY DESIGN

Breast milk was prospectively collected (four times) on postpartum days 6 to 8, 13 to 15, 20 to 22 and 27 to 29 from 15 mothers who had delivered between 24 and 31 weeks of gestation. Skimmed milk was assayed to measure TAC and bio-active proteins (lysozyme, lactoferrin, leptin and adiponectin). The association between TAC and levels of bio-active proteins during the first month of lactation was analyzed in a regression model.

RESULT

Coefficient of determinations (R(2)) revealed an overall effect of bio-active proteins on breast milk TAC (R(2)=0.635+/-0.102, P<0.0001). Breast milk leptin, lysozyme and lactoferrin levels were identified as independent factors that significantly predict the concentration of TAC.

CONCLUSION

The identified enhancement of the antioxidant capacity of human milk by bio-active proteins that are lacking in commercial formula supports consideration of breast milk as ideal nutrition for preterm-born neonates.

Effect of Holder pasteurization and frozen storage on macronutrients and energy content of breast milk

OBJECTIVES

The aim of this study was to explore the effect of Holder pasteurization and frozen storage at -20°C after pasteurization on fat, total nitrogen, lactose, and energy content of breast milk. Both procedures are routinely practiced in human milk banks.

METHODS

A total of 34 samples of frozen breast milk, donated by 28 women, were collected. Once thawed, an aliquot of each sample was analyzed before pasteurization; the remaining milk was pasteurized (Holder method) and split into 8 aliquots. One aliquot was analyzed after pasteurization and the remainder frozen at -20°C and analyzed 30, 60, 90, 120, and 180 days later. For every aliquot, fat, total nitrogen, lactose, and energy content were determined using the device human Milk Analyzer.

RESULTS

We observed a significant reduction in fat (3.5%; -0.17 (-0.29; -0.04) g/dL) and energy content (2.8%; -2.03 (-3.60; -0.46) g/dL) after pasteurization. A significant decrease over time was observed for fat, lactose and energy content. No significant changes were observed for nitrogen content. Mean differences between day 0 postpasteurization and day 180 were -0.13 (-0.21; -0.06) g/dL for fat, -0.08 (-0.13; -0.03) g/dL for lactose, and -1.55 (-2.38; -0.71) kcal/dL for energy content. The relative decreases were 2.8%, 1.7%, and 2.2%, respectively. Overall (postpasteurization + frozen storage), a 6.2% and 5% decrease were observed for fat and energy, respectively.

CONCLUSIONS

Holder pasteurization decreased fat and energy content of human milk. Frozen storage at -20°C of pasteurized milk significantly reduced fat, lactose, and energy content of human milk.

Resonance Raman spectroscopy and the preterm infant carotenoid status

OBJECTIVE

The aim of the study was to validate the noninvasive resonance Raman spectroscopy (RRS) method in infants in comparison with the high-performance liquid chromatography (HPLC) method, and to evaluate the carotenoid status in preterm infants fed with mother's milk or formula.

METHODS

In the first phase of the study, resonance Raman measurements were made on male term infants' skin and correlated with tissue harvested at the time of circumcision. Each baby's foreskin was weighed, enzymatically digested, and the total carotenoids were extracted and quantitated by the HPLC. Next, to evaluate the carotenoid status of preterm infants (BW <1500 g), the skin and serum carotenoids in infants fed with either human milk or preterm formula were studied from the start of feedings and every 2 weeks until hospital discharge. Skin carotenoids were measured by RRS and the serum total carotenoids by HPLC.

RESULTS

Foreskin carotenoid levels measured by RRS correlated with HPLC measurements of total serum carotenoids (R = 0.52, P < 0.01, n = 16). Forty preterm infants were studied for their carotenoid status. Thirty-two infants were fed mother's milk, whereas 8 were fed a preterm infant formula that was not enriched with carotenoids. The gestation and birth weight of the 2 feeding groups were similar. The infants fed human milk had a higher serum total carotenoid concentration and skin Raman counts than formula-fed infants. The skin Raman counts and total serum carotenoid correlated (R = 0.44, P = 0.01). The human milk-fed infants' serum total carotenoid concentrations and Raman values did not change during the study period; however, the formula-fed group's total serum and skin carotenoid decreased significantly during the study.

CONCLUSIONS

RRS of infant's skin reliably assesses total carotenoid status noninvasively. Human milk-fed preterm infants have higher serum and skin carotenoids than formula-fed infants suggesting that formula-fed infants may benefit from carotenoid supplementation.

Effect of prolonged refrigeration on the lipid profile, lipase activity, and oxidative status of human milk

OBJECTIVE

The study was aimed at evaluating the effect of prolonged refrigeration of fresh human milk (HM) on its fatty acid profile, free fatty acid content, lipase activities, and oxidative status.

METHODS

HM from mothers of preterm newborns was collected, pooled, and placed in the neonatal intensive care unit (NICU) refrigerator. Pooled milk was aliquoted and analyzed within 3 hours of collection, and after 24, 48, 72, and 96 hours of storage. The milk samples were analyzed for pH, total and free fatty acid profile, lipase activity at room temperature and at 4°C, lipase activity at room temperature in presence of sodium cholate (bile salt-dependent lipase), total antioxidant capacity, thiobarbituric acid reactive species, malondialdehyde, and conjugated diene concentration. The experiment was replicated in 3 independent trials.

RESULTS

Prolonged refrigeration did not affect the fatty acid composition of breast milk, and preserved both its overall oxidative status and the activity of HM lipolytic enzymes. In particular, bile salt-dependent lipase activity, long-chain polyunsaturated fatty acids, and medium-chain saturated fatty acid concentrations were unaffected for up to 96 hours of refrigerated storage.

CONCLUSIONS

Prolonged refrigeration of fresh HM for 96 hours maintained its overall lipid composition. The limited lipolysis during storage should be ascribed to the activity of lipoprotein lipase, responsible for the decrease in pH. Our study demonstrates that infants who receive expressed milk stored for up to 96 hours receive essentially the same supply of fatty acids and active lipases as do infants fed directly at the breast.

Biological determinants linking infant weight gain and child obesity: current knowledge and future directions

Childhood obesity rates have reached epidemic proportions. Excessive weight gain in infancy is associated with persistence of elevated weight status and later obesity. In this review, we make the case that weight gain in the first 6 mo is especially predictive of later obesity risk due to the metabolic programming that can occur early postpartum. The current state of knowledge regarding the biological determinants of excess infant weight gain is reviewed, with particular focus on infant feeding choice. Potential mechanisms by which different feeding approaches may program the metabolic profile of the infant, causing the link between early weight gain and later obesity are proposed. These mechanisms are likely highly complex and involve synergistic interactions between endocrine effects and factors that alter the inflammatory and oxidative stress status of the infant. Gaps in current knowledge are highlighted. These include a lack of data describing 1) what type of infant body fat distribution may impart risk and 2) how maternal metabolic dysfunction (obesity and/or diabetes) may affect milk composition and exert downstream effects on infant metabolism. Improved understanding and management of these early postnatal determinants of childhood obesity may have great impact on reducing its prevalence.