In this study, researchers characterized the gut microbiota of breastfeeding mothers after collecting fecal samples from 2 days to 6 months postpartum. They found that the women’s gut bacterial communities were similar to those found in other adults; the gut communities were also relatively stable over the postpartum period.

Researchers also found associations between dietary components and the relative abundances of certain bacterial taxa: Increased Prevotella and decreased Bacteroides were associated with higher intakes of pantothenic acid, riboflavin, vitamin B6, and vitamin B12 in this group of women, while increased Firmicutes and decreased Bacteroidetes were correlated with higher intakes of copper, magnesium, manganese, and molybdenum.

Results showed that, overall, a diet higher in nutrients and calories was associated with more Firmicutes in the gut. Causality remains unclear, however, and scientists know little about the relationship between women’s health and the relative abundances of different bacteria.


Carrothers JM, et al. (2015) Fecal Microbial Community Structure Is Stable over Time and Related to Variation in Macronutrient and Micronutrient Intakes in Lactating Women. Journal of Nutrition doi: 10.3945/​jn.115.211110