Microbiota Composition of Breast Milk from Women of Different Ethnicity from the Manawatu—Wanganui Region of New Zealand

Abstract

Human breastmilk components, the microbiota and immune modulatory proteins have vital roles in infant gut and immune development. In a population of breastfeeding women (n = 78) of different ethnicities (Asian, Māori and Pacific Island, New Zealand European) and their infants living in the Manawatu–Wanganui region of New Zealand, we examined the microbiota and immune modulatory proteins in the breast milk, and the fecal microbiota of mothers and infants. Breast milk and fecal samples were collected over a one-week period during the six to eight weeks postpartum. Breast milk microbiota differed between the ethnic groups. However, these differences had no influence on the infant’s gut microbiota composition. Based on the body mass index (BMI) classifications, the mother’s breast milk and fecal microbiota compositions were similar between normal, overweight and obese individuals, and their infant’s fecal microbiota composition also did not differ. The relative abundance of bacteria belonging to the Bacteroidetes phylum was higher in feces of infants born through vaginal delivery. However, the bacterial abundance of this phylum in the mother’s breast milk or feces was similar between women who delivered vaginally or by cesarean section. Several immune modulatory proteins including cytokines, growth factors, and immunoglobulin differed between the BMI and ethnicity groups. Transforming growth factor beta 1 and 2 (TGFβ1, TGFβ2) were present in higher concentrations in the milk from overweight mothers compared to those of normal weight. The TGFβ1 and soluble cluster of differentiation 14 (sCD14) concentrations were significantly higher in the breast milk from Māori and Pacific Island women compared with women from Asian and NZ European ethnicities. This study explores the relationship between ethnicity, body mass index, mode of baby delivery and the microbiota of infants and their mothers and their potential impact on infant health.

The human milk microbiome aligns with lactation stage and not birth mode

“…Our study revealed no impact of maternal BMI on milk microbiome diversity. This finding was also reported across several other studies 16 , 33 , 62 . However, Cabrera-Rubio et al reported that maternal BMI and weight gain during pregnancy had an impact on bacterial composition and diversity in breast milk, with high BMI associated with a decrease in diversity.…”

Breastfeeding Practices Influence the Breast Milk Microbiota Depending on Pre-Gestational Maternal BMI and Weight Gain over Pregnancy

“…Indeed, recent evidence has shown breastfeeding practices and milk collection methods would influence breast milk microbiota composition [ 9 ]. Results regarding the potential impact of maternal body mass index (BMI) and weight gain over pregnancy on breast milk microbiota are also still contradictory [ 13 , 14 , 15 , 16 ]. Similarly, while other studies found differences in milk microbiota according to lactation period [ 13 , 17 ] and feeding method [ 9 ], others reported a stable composition over time [ 18 ].…”

Best Practices for Human Milk Collection for COVID-19 Research

“…50 There are similar findings for human milk. 51,52 Although findings are somewhat mixed, [53][54][55] there is substantial evidence that some soluble factors and characteristics (e.g., antioxidant capacity) in milk can be influenced by refrigeration and freezing, whereas others (e.g., human milk oligosaccharides) are extraordinarily stable. [56][57][58] It has been shown that prolonged storage at 4°C reduces the infectious titer of hepatitis C and Zika virus that has been spiked into milk.…”