Three New Studies on Human Milk

Title: Glycerol Monolaurate Contributes to the Antimicrobial and Anti-inflammatory Activity of Human Milk.

In: Scientific Reports 2019 Oct 10;9(1):14550. doi: 10.1038/s41598-019-51130-y.

Authors: Schlievert PM, Kilgore SH, Seo KS, Leung DYM.

Abstract: "Human milk has antimicrobial compounds and immunomodulatory activities. We investigated glycerol monolaurate (GML) in human milk versus bovine milk and infant formula for antimicrobial and anti-inflammatory activities. Human milk contained approximately 3000 µg/ml of GML, compared to 150 μg/ml in bovine milk and none in infant formula. For bacteria tested (Staphylococcus aureus, Bacillus subtilis, Clostridium perfringens, Escherichia coli), except Enterococcus faecalis, human milk was more antimicrobial than bovine milk and formula. The Enterococcus faecalis strain, which was not inhibited, produced reutericyclin, which is an analogue of GML and functions as a growth stimulant in bacteria that produce it. Removal of GML and other lipophilic molecules from human milk by ethanol extraction resulted in a loss of antibacterial activity, which was restored by re-addition of GML. GML addition caused bovine milk to become antimicrobial. Human milk but not bovine milk or formula inhibited superantigen and bacterial-induced IL-8 production by model human epithelial cells. GML may contribute beneficially to human milk compared to bovine milk or infant formula."

Full text: https://www.nature.com/articles/s41598-019-51130-y

Title: Human Milk Retains Important Immunologic Properties After Defatting.

In: JPEN Journal of Parenteral and Enteral Nutrition 2019 Oct 9. doi: 10.1002/jpen.1722. [Epub ahead of print]

Authors:: Jackson BA, Gregg BE, Tutor SD, Bermick JR, Stanley KP.

Abstract:

"Background: In neonatal chylothorax, thoracic lymphatic drainage is ineffective. The resultant effusions often require drainage, leading to a loss of immune components. Affected infants can be managed with formula or defatted human milk feedings low in long-chain triglycerides to decrease lymph production. We hypothesized that there is no significant difference in the immunological profile or antibacterial effect of full-fat and defatted human milk.”

"Methods: Milk from lactating mothers was divided into 1 aliquot that was defatted via centrifugation with the full-fat aliquot as control. Macronutrient content was analyzed with mid-infrared spectroscopy. Flow cytometry was used to measure immune cell populations. Lactoferrin, lysozyme, immunoglobulin (Ig)A, and IgG values were determined using enzyme-linked immunosorbent assay. The antibacterial properties were determined by inoculating paired full-fat and defatted milk samples with Escherichia coli or Streptococcus pneumoniae bacteria and performing colony counts."

"Results: Compared with full-fat milk, defatted milk demonstrated decreased total energy and fat and increased carbohydrate concentrations. Defatted milk demonstrated a significant decrease in all immune cell populations. There was no difference in IgA, IgG, lysozyme, or lactoferrin concentrations. Both aliquots demonstrated equivalent growth inhibition of E. coli and S. pneumoniae."

"Conclusions: Unexpectedly, defatted human milk contained significantly less leukocytes than full-fat milk. IgA, IgG, lysozyme, and lactoferrin concentrations were preserved. The ability of defatted milk to inhibit bacterial growth was unaffected, suggesting that the antibacterial benefits of human milk remain after the defatting process. Further investigation regarding the clinical effect of leukocyte loss in defatted milk is warranted."

Abstract only: https://onlinelibrary.wiley.com/doi/abs/10.1002/jpen.1722

Title: Comparison of Oxidative Status of Human Milk, Human Milk Fortifiers and Preterm Infant Formulas.

In: Foods 2019 Oct 8;8(10). pii: E458. doi: 10.3390/foods8100458.

Authors: Pozzo L, Cirrincione S, Russo R, Karamać M, Amarowicz R, Coscia A, Antoniazzi S, Cavallarin L, Giribaldi M.

Abstract: "Preterm and low birth weight infants require specific nutrition to overcome the accumulated growth deficit, and to prevent morbidities related to postnatal growth failure. In order to guarantee an adequate nutrient-intake, mother's own milk, when available, or donor human milk, are usually fortified with additional nutrients, in particular proteins. Fortification with processed ingredients may result in additional intake in oxidative compounds, deriving from extensive heat treatments, that are applied during processing. The aim of the present work was to compare the in vitro antioxidant activity and oxidative compound content conveyed by different preterm infant foods and fortifiers, namely raw and pasteurized human milk, two different preterm infant formulas, three bovine milk-based fortifiers and two experimental donkey milk-based fortifiers. Univariate and multivariate statistical analyses revealed significant differences between the different products. The use of human milk minimizes the intake of dietary oxidative compound in comparison to infant formulas, irrespective of pasteurization or fortification, especially as far as malondialdehyde content is concerned. The addition of fortifiers to human milk increases its antioxidant capacity, and the choice of the protein source (hydrolysed vs. whole proteins) differently impacted the resulting total antioxidant capacity of the diet."

Full text: https://www.mdpi.com/2304-8158/8/10/458