A Study on Microbial and Macronutrient Composition of Breast Milk Varies with Lactation Duration

Anju Dhar,Madhavi Dhobale,Urmila Deshmukh,Vinit Warthe,Yagnesh Thakar

doi:10.9734/jpri/2021/v33i44a32583

Abstract

Complementary feeding and continuation of breast feeding is directed and advised by the national and international child health agencies. Breast milk, a complex biological fluid, shows changes in its cellular, microbial and nutrient composition as lactation progresses. In a cross-sectional study, hospital-based pilot project showed the composition of microbial and macronutrients and compared their differences before and after first six months of lactation. Staphylococcus aureus was the predominant bacterium found in breast milk, and 45% (15/33) of samples within first six months and only 13% (3/22) from those more than six months of lactation showed any bacterial growth (p=0.013). The protein content was less in breast milk samples after six months compared to those within six months of lactation (mean difference, 95% CI: 0.33 (0.10, 0.55) gm/dL, p=0.005). After controlling the lactation period, bacterial culture positivity in breast milk was associated directly with the breast milk protein content. Our pilot study observations indicate the need to study microbial and nutrient changes in breast milk as lactation advances, in a longitudinal study with larger sample size, and investigate its associations with maternal factors, infant growth, establishment of infant gut microbiota and possible role in environmental enteric dysfunction.

Highlights

Breast milk is the only source of nutrition to the new born baby for the first six months of its life
Breast milk samples from 18 (33%) lactating women showed some bacterial growth, whereas 37 (67%) samples did not show any microbial growth. Out of these 18 samples who tested positive for bacterial growth were further isolated and identified the organisms as Staphylococcus aureus in 14 samples, Kleibseilla oxytoca in 3 samples [9], and both the bacteria, Staphylococcus and Kleibseilla in one sample Similar study suggests that as the infant microbiome establishes in the initial weeks after birth, human milk may show changes in the cellular composition
Our study showed that even after controlling the lactation duration, frequency of positive bacterial growth was associated with the protein content of breast milk [14]

Summary

Introduction

Breast milk is the only source of nutrition to the new born baby for the first six months of its life. Strong epidemiological evidence shows the advantages of breast milk for infants morbidity, including decreased risk of atopic dermatitis, asthma, necrotizing enter colitis, gastroenteritis and respiratory tract infections, obesity and type 2 diabetes [1]. Breast milk includes a variety of physiologically active components like lipids, oligosaccharides, immunological micro RNAs, hormones and cellular components. The breastfeeding skin for mothers, the mouth of her child, and some transfers from the maternal gastrointestinal system are known to cause the breast milk micro biome (entero-mammary path). The breast milk bacteria are believed to influence health of the mammary glands, colonizing infants gut, and maturation of gut immune system. Infants gut microbiota is shown to influence morbidity outcomes such as gut and respiratory tract infections, asthma, metabolic syndrome and inflammatory bowel disease [3]

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