Breast milk dominant phyla and probiotic bacteria population in obese lactating women: a case-control study

Abstract Background The main purpose was to determine amount of dominant phyla, Bifidobacteria and Lactobacillus in breast milk of obese mothers versus normal at 3rd of lactation in Iranian population. Methods Eighty health women at the third month of lactation, without any chronic, and gastrointestinal disorders were included and categorized base on body mass index (BMI) to two groups as obese (BMI ≥ 30 kg/m2) and normal (18.5 < BMI < 24.9). Bacterial DNA was extracted and qPCR of the 16S region was performed after human milk donation in sterile conditions. A linear regressions model was used to determine the baseline parameters on the population. Results Bifidobacteria population was significantly higher in normal group than obese mothers. Current BMI showed a significant effect on the Actinobacteria population in milk. Bacteroidetes and Firmicutes population were significantly lower in mother’s milk with cesarean delivery (p = 0.04). Pre-pregnancy obesity was associated with lower Firmicutes and Lactobacillus population in maternal milk (p = 0.04 and p = 0.01). A significant association was observed between the infant height with Actinobacteria and Bifidobacteria population of milk (p = 0.008 and p = 0.04). Conclusions Current and pre-pregnancy obesity are associated with lower beneficial phylum and probiotic bacteria in breast milk. Both of them are associated with infant’s height.