The effects of breast milk storage and freezing procedure on interleukine-10 levels and total antioxidant activity

The effects of freezing and thawing on mature human milk's contains: A systematic review

OBJECTIVE

To conduct a systematic review on the effects of freezing and thawing mature human milk at -18 to -20°C for different periods of time on the macronutrients, micronutrients and bioactive content of milk.

DESIGN

Before starting the research, the study protocol was recorded in the 'PROSPERO' database. Eleven databases were searched, and eight studies were included in this review. The articles were published between January 2010 and June 2020.

MEASUREMENTS AND FINDINGS

Total protein content increased when milk was frozen for 2 days, but this decreased significantly when milk was frozen for >1 week. Total carbohydrate content also increased when milk was frozen for 2 days, and no significant change was observed when milk was frozen for >1 week. Energy content decreased when milk was frozen for >8 weeks. Total fat content decreased as the freezing period of milk increased, and total free fatty acid content increased. Thirty days of freezing led to a non-significant decrease in the vitamin E content of milk. Freezing did not lead to changes in immunological factors in human milk, but decreases in glutathione peroxidase, antioxidant capacity and lactoferrin were observed.

KEY CONCLUSIONS

In order to maintain the nutritional and immunological properties of human milk after freezing and thawing, families, especially mothers, should be informed about the effects of storing milk this way. After expressing milk, it is recommended that the date should be written on the freezer bag, so that milk is frozen for a shorter period of time before use.

The Role of Glycosaminoglycans in Protection from Neonatal Necrotizing Enterocolitis: A Narrative Review

Necrotizing enterocolitis, a potentially fatal intestinal inflammatory disorder affecting primarily premature infants, is a significant cause of morbidity and mortality in neonates. While the etiology of the disease is, as yet, unknown, a number of risk factors for the development of necrotizing enterocolitis have been identified. One such risk factor, formula feeding, has been shown to contribute to both increased incidence and severity of the disease. The protective influences afforded by breastfeeding are likely attributable to the unique composition of human milk, an extremely potent, biologically active fluid. This review brings together knowledge on the pathogenesis of necrotizing enterocolitis and current thinking on the instrumental role of one of the more prominent classes of bioactive components in human breast milk, glycosaminoglycans.

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.

Availability of Donor Milk for Very Preterm Infants Decreased the Risk of Necrotizing Enterocolitis without Adversely Impacting Growth or Rates of Breastfeeding

Human milk contains non-nutritional factors that promote intestinal maturation and protect against infectious and inflammatory conditions. In the Neonatal Intensive Care Unit (NICU) setting, donor milk (DM) is recommended when availability of own mother's milk (OMM) is not enough. Our aim was to compare the incidence of necrotizing enterocolitis (NEC) and late-onset sepsis (LOS) in very preterm infants (VPI) after the introduction of DM. Growth and breastfeeding rates were examined as secondary outcomes. Single center, observational and retrospective cohort study comparing 227 VPI admitted to our neonatal unit before (Group 1, n = 99) and after (Group 2, n = 128) DM introduction. Enteral nutrition was started earlier after DM availability (2.6 ± 1.1 vs. 2.1 ± 1 days, p = 0.001). Incidence of NEC decreased in group 2 (9.1% vs. 3.4%, p = 0.055), especially in those born between 28 and 32 weeks (5.4 vs. 0.0%, p = 0.044). Surgical NEC was also less frequent. Suffering NEC was 4 times more likely in group 1 (multivariate analysis). Availability of DM did not impact breastfeeding rates or preterm growth. Our findings support the protective role of DM against NEC, particularly in non-extreme VPI, a group less frequently included in clinical guidelines and research studies on the use of DM.

Impact of human milk on the transcriptomic response of fetal intestinal epithelial cells reveals expression changes of immune-related genes

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment.

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment. The protective role of human milk is well known although the mechanisms behind it still need to be uncovered. This study aimed to characterize the impact of human milk in the immature intestine of newborns by analyzing the global transcriptomic response of the FHs 74 int cell line (ATCC CCL-241). The expression of intestinal keratins and other genes with a well-annotated intestinal or epithelial function validated FHs 74 int derived from the fetal small intestine as a model of the intestinal epithelium of newborns. Cells exposed to skimmed human milk showed seventeen differentially expressed genes, most of them up-regulated, including four chemokine genes (CXCL1, CXCL2, CXCL3 and CXCL10) and other immune-related genes. qRT-PCR and ELISA analysis confirmed the microarray data and indicated a different pattern of expression upon milk exposure in FHs 74 int as compared to the adult tumorigenic Caco-2 cell line. The evaluation of the functional significance of these transcriptomic changes reveals that human milk exposure may contribute to the regulation of the inflammatory response in the intestine during the perinatal period, which is characterized by the immaturity of the immune system and a pro-inflammatory phenotype.

Review concludes that specific recommendations are needed to harmonise the provision of fresh mother's milk to their preterm infants

AIM

There are no specific recommendations for using a mother's fresh milk for her preterm infant. We reviewed the available evidence on its collection, storage and administration.

METHODS

The working group of the French Neonatal Society on fresh human milk use in preterm infants searched the MEDLINE database and Cochrane Library up to June 2017 for papers published in English or French. They specifically analysed 282 papers providing information on prospective, retrospective and clinical studies and examined guidelines from various countries.

RESULTS

The review concluded that fresh mother's own milk should be favoured in accordance with the latest recommendations. However, it must be carried out under stringent conditions so that the expected benefits are not offset by risks related to different practices. The working group has summarised the best conditions for feeding preterm infants with human milk, balancing high nutritional and immunological quality with adequate virological and bacteriological safety. Professionals must provide parents with the necessary conditions to establish breastfeeding, together with specific and strong support.

CONCLUSION

Based on their review, the working group has made specific recommendations for using fresh mother's own milk under careful conditions, so that the expected benefits are not offset by risks related to practices.

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.

Mothers' Consumption of Soy Drink But Not Black Tea Increases the Flavonoid Content of Term Breast Milk: A Pilot Randomized, Controlled Intervention Study

OBJECTIVE

We performed a pilot RCT to prove the hypothesis that a controlled ingestion of polyphenol-rich beverages (soy drink, decaffeinated black tea) in nutritive dosages by nursing women has an effect on the composition (flavonoid concentration, total antioxidant capacity) of breast milk.

METHODS

Healthy nursing women were supplemented with either 250 mL of a soy drink (12 mg isoflavones; n = 18), 300 mL decaffeinated black tea (67 mg catechins; n = 18), or 300 mL water (n = 8, control) for 6 days. Milk samples were collected before, during, and after intervention. Flavonoid content (isoflavones/catechins, HPLC) and total antioxidant capacity of milk and test drinks in milk specimens were assessed.

RESULTS

Isoflavone content (genistein and daidzein) in breast milk increased up to 12 nmol/L after soy drink consumption; the major flavonoids constituents of black tea (catechin, epicatechin, and respective conjugates) could not be detected in milk samples. With both interventions, the total antioxidant capacity of breast milk was not affected.

CONCLUSIONS

Mothers' daily consumption of a soy drink considerably increases isoflavone content of breast milk resulting in an estimated daily exposure of 9.6 nmol isoflavones in a 4-month-old suckling infant. Luminal flavanol uptake from black tea consumed by the nursing mother may be too low to affect flavanol concentrations in breast milk.

The Effect of Freeze-Drying on the Nutrient, Polyphenol, and Oxidant Levels of Breast Milk

OBJECTIVES

Human milk banks need to extend the suitability of milk for breastfeeding, and for this technological advances are required. Our aim was to establish the capacity of freeze-drying to conserve milk properties without further oxidative deterioration.

METHODS

One hundred sixteen healthy women participated from the city of Cordoba (Argentina). Proteins, glucose, triglycerides, polyphenols, and markers (nitrites, superoxide anion, hydroperoxides, lipoperoxides, and γ-glutamyl transpeptidase) were measured in their fresh milk. Samples were then separated for three treatments as follows: freezing and conservation for 6 months at -80°C (F: positive control); freeze-drying for 24 hours at ≤-70°C and ≤1.33 Pa and conservation for 6 months at 4°C (FD: treatment of interest); and freeze-drying for 24 hours at ≤-70°C and ≤1.33 Pa and conservation for 6 months at -80°C (FD+F). Next, analyses were repeated and compared by ANOVA and Tukey tests.

RESULTS

Fresh milk showed these values per L as follows: proteins: 12.62 ± 2.51 g, glucose: 4.44 ± 0.25 g, triglycerides: 34.26 ± 0.59 g, polyphenols: 53.27 ± 8.67 mg, nitrites: 62.40 ± 19.09 mg, superoxide: 3,721.02 ± 198.80 OD, hydroperoxides: 7,343.76 ± 294.53 OD, lipoperoxides: 7,349.72 ± 398.72 OD, and γ-glutamyl transpeptidase: 4.66 ± 0.55 IU. Glucose was decreased after F treatment (p < 0.05), all variables were conserved by FD and were not improved by the FD + F combination.

CONCLUSIONS

Freeze-drying achieved suitable conservation and may improve bank functioning, by protecting nutritional properties, polyphenol-related functionality, and oxidative integrity of human milk through a 1-day treatment with easy maintenance.

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.