Fecal Microbial Community Structure Is Stable over Time and Related to Variation in Macronutrient and Micronutrient Intakes in Lactating Women

Background: The fecal microbiota has been c'haracterized in some adult populations, but little is known about its community structure during lactation. Objectives: We characterized the maternal fecal microbiome during lactation-and explored possible mediating factors such as nutrition. Methods: Fecal samples were collected from 20 lactating women from 2 d to 6 mo postpartum, and bacterial taxa were characterized with the use of high-throughput sequencing. Bacterial community structure (at each taxonomic level) and relations between bacterial taxa and environmental and dietary variables were visualized and analyzed with the use of stacked bar charts, principal component analysis, and-multivariate analyses such as nonmetric multidimensional scaling and canonical correlation analysis. Results: Complex bacterial community structure was somewhat similar to those previously published for other adult populations (although there were some notable differences), and there were no clear associations with time postpartum or anthropometric or environmental variables. However, Spearman rank correlations suggested that increased intake of pantothenic acid, riboflavin, vitamin B-6,-and vitamin-B-12 were related to increased relative abundance of Prevotella (r= 0.45, 0.39, 0 34, and 0.24, respectively; P <= 0.01) and decreased relative abundance of Bacteroides (r = -0.55, -0.46, -0.32, and -0.35, respectively; P <= 0.011. Intakes of copper, magnesium, manganese, and mdlybdenum were positively associated with Firmicutes (r= 0.33, 0.38, 0.44, and 0.51, respectively; P <= 0.011 and negatively associated with Bacteroidetes (r = 0.38, 0.44, 0.48, -and 0.53, respectively; P <= 0.01). Overall,-data consistently suggest that increased consumption of a more nutrient- and calorie-rich-diet was positively associated with relative abundance of Firmicutes. Conclusions: The fecal microbiome of lactating women is relatively stable in the.postpartum period and somewhat similar -to that of other adult populations. Variation in dietary constituents may be related to that of relative abundance of individual bacterial taxa. Controlled dietary intervention Studies will be required to determine whether these associations are causal in nature.