Bacterial Diversity of Breast Milk in Healthy Spanish Women: Evolution from Birth to Five Years Postpartum.

Laura Sanjulián,Alexandre Lamas,Patricia Regal,Alberto Cepeda,Rocío Barreiro,Cristina A. Fente

doi:10.3390/nu13072414

Laura Sanjulián, Alexandre Lamas + Show 4 more

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https://doi.org/10.3390/nu13072414

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Journal: Nutrients	Publication Date: Jul 14, 2021
Citations: 10	License type: CC BY 4.0

Affiliation: University of Santiago de Compostela

Abstract

The objective of this work was to characterize the microbiota of breast milk in healthy Spanish mothers and to investigate the effects of lactation time on its diversity. A total of ninety-nine human milk samples were collected from healthy Spanish women and were assessed by means of next-generation sequencing of 16S rRNA amplicons and by qPCR. Firmicutes was the most abundant phylum, followed by Bacteroidetes, Actinobacteria, and Proteobacteria. Accordingly, Streptococcus was the most abundant genus. Lactation time showed a strong influence in milk microbiota, positively correlating with Actinobacteria and Bacteroidetes, while Firmicutes was relatively constant over lactation. 16S rRNA amplicon sequencing showed that the highest alpha-diversity was found in samples of prolonged lactation, along with wider differences between individuals. As for milk nutrients, calcium, magnesium, and selenium levels were potentially associated with Streptococcus and Staphylococcus abundance. Additionally, Proteobacteria was positively correlated with docosahexaenoic acid (DHA) levels in breast milk, and Staphylococcus with conjugated linoleic acid. Conversely, Streptococcus and trans-palmitoleic acid showed a negative association. Other factors such as maternal body mass index or diet also showed an influence on the structure of these microbial communities. Overall, human milk in Spanish mothers appeared to be a complex niche shaped by host factors and by its own nutrients, increasing in diversity over time.

Highlights

IntroductionIts composition is highly complex and variable over time, showing different profiles adapted to the newborn requirements, health status, growth, and development
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Ninety-nine samples of breast milk from healthy Spanish mothers were analysed, demonstrating that the microbiota of this fluid is influenced by time, becoming more diverse and more distinctive of the individual as lactation progresses in time

Summary

Introduction

Its composition is highly complex and variable over time, showing different profiles adapted to the newborn requirements, health status, growth, and development For these reasons, the WHO recommends exclusive on-demand breastfeeding during the first 6 months of life and advises that it should continue for up to two years of age or beyond in combination with complementary foods. Breastfeeding grants protection against diarrhoea, necrotising enterocolitis, respiratory infections, and atopic dermatitis, and decreases the risk of non-communicable diseases, including type 2 diabetes mellitus, overweight, and obesity, and it is closely related to low rates of infant mortality [1,2,3]. This extraordinary maternal fluid contains a wide range of essential nutrients and different bioactive components such as proteins, oligosaccharides, minerals, lipids, vitamins, immune factors, microRNAs, and hormones, which altogether explain its important health benefits for the infant [4,5,6]

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