Distinct associations among human milk microbiota and minerals in relation to early infant growth: a longitudinal study

Currently there is a knowledge gap in relation to the interaction of milk components and their association with infant growth. Our aim was to analyze the associations between minerals and the milk microbiome and how they associate with infant growth in the Mam-Mayan indigenous population of Guatemala. In this longitudinal study, a total of 114 milk samples were collected from 57 mothers during early (5–46 days) and established (4–6 months) lactation. Concentrations of 12 milk minerals were analyzed. Infant growth was assessed according to the infant growth parameters [weight-for-age (WAZ) and head circumference-for-age (HCAZ) into ≥−1 SD and <−1 SD and length-for-age (LAZ) into ≥−2 SD and <−2 SD]. The milk microbiome diversity was obtained by 16S rRNA gene amplicon sequencing of the V5–V6 region. The milk microbiome diversity differed between infants with normal and impaired growth in weight and length during early lactation, but not in established lactation. In established lactation, milk microbiome diversity only differed between infants with normal and impaired head circumference. Some bacteria could be associated with normal growth, such as Luteococcus peritonei (for all growth parameters measured, that is WAZ, LAZ and HCAZ), Bifidobacterium longum, Lancefieldella parvula, Phascolarctobacterium, Rothia mucilaginosa, Streptococcus agalactiae and Streptococcus pneumoniae (only for the LAZ and HCAZ), Janthinobacterium lividum (only WAZ) and Lactobacillus johnsonii (only HCAZ parameter). Similarly, C. acnes could be associated with impaired growth as it was identified in infants with impaired WAZ and LAZ. Manganese and magnesium emerged as key minerals due to their high number of correlations with the milk microbiome in both normal and impaired growth. Namely, Cutibacterium acnes was differentially abundant (DA) in the mildly underweight and stunted infants and was negatively associated with manganese. On the other hand, in non-stunted and normal head circumference infants Phascolarctobacterium and Streptococcus agalactiae were positively associated with magnesium, and Streptococcus pneumoniae was positively associated with manganese. Milk microbial composition was associated with milk mineral concentrations, and both were associated with infant growth status. ClinicalTrials.gov ID NCT02755012 (http://Clinicaltrials.gov/study/NCT02755012). Retrospectively Registered 2016–04-26