The infant gut microbiota at 12 ​months of age is associated with human milk exposure but not with maternal pre-pregnancy body mass index or infant BMI-for-age z-scores

Abstract

Background: As obesity rates continue to rise, it is increasingly important to understand factors that can influence body weight and growth, especially from an early age. The infant gut microbiota has broad effects on a variety of bodily processes, but its relation to infant growth is not yet fully characterized. Since the infant gut microbiota is closely related to breastfeeding practices and maternal health, understanding the relationship between these factors and infant growth may provide insight into the origins of childhood obesity. Objectives: Identify the relationship between human milk exposure, maternal pre-pregnancy body mass index (BMI), the infant gut microbiota, and 12-month-old BMI-for-age z-scores (12M BAZ) to identify key factors that shape infant growth. Methods: Two Michigan cohorts (ARCHGUT and BABYGUT) comprised of a total of 33 mother-infant dyads provided infant fecal samples at 12M. After DNA extraction, amplification, and sequencing of the V4 16S rRNA region using Illumina MiSeq v2 Chemistry, gut bacterial diversity metrics were analyzed in relation to human milk exposure, maternal pre-pregnancy BMI, and infant growth parameters. Results: Recent human milk exposure was inversely related to maternal pre-pregnancy BMI and most strongly associated with infant gut bacterial community membership and individual gut microbiota richness differences. Maternal pre-pregnancy BMI was not associated with the infant gut microbiota after adjusting for human milk exposure. However, maternal pre-pregnancy BMI was the only factor significantly associated with 12M BAZ. Conclusions: Human milk exposure is one of the central influences on the infant gut microbiota at 12M of age. However, the lack of association between the infant gut microbiota and 12M-old infant BAZ suggests that genetic, physiological, dietary, and other environmental factors may play a more direct role than the gut microbiota in determining infant BAZ at 12M.

Composition of Human Breast Milk Microbiota and Its Role in Children’s Health

“…Obesity is one of the most prevalent non-communicable diseases worldwide as well as in pediatric patients. Therefore, it is important to understand the potential causes to reduce the prevalence and associated morbidities [ 61 ]. In this regard, the mode of delivery, maternal health, antibiotic exposure, and breastfeeding are considered as factors that play a pivotal role in altering the infant gut microbiota and, subsequently, the probability of obesity onset in children [ 61 ].…”

“…Therefore, it is important to understand the potential causes to reduce the prevalence and associated morbidities [ 61 ]. In this regard, the mode of delivery, maternal health, antibiotic exposure, and breastfeeding are considered as factors that play a pivotal role in altering the infant gut microbiota and, subsequently, the probability of obesity onset in children [ 61 ]. It has been demonstrated that breastfed infants have a lower incidence and risk of obesity than formula-fed infants.…”

Fecal microbiota relationships with childhood obesity: A scoping comprehensive review

“…Taking together all the information available, breast milk has been considered as a probiotic food for infants 99 . Understanding, bacterial colonization patterns related to solid food intake will enable personalized nutrition to prevent obesity in childhood, 100 where maternal lactation until 12 months appears as more important than BMI of the mother/child 101 …”

Archive for Research in Child Health (ARCH) and Baby Gut: Study Protocol for a Remote, Prospective, Longitudinal Pregnancy and Birth Cohort to Address Microbiota Development and Child Health

“…Although maternal pre-pregnancy BMI was associated with significantly greater infant gut microbial diversity (Chao1, p = 0.01; Shannon, p = 0.04), a bivariate analysis revealed that human milk exposure was the likely driver of this observed association (Chao1, p = 0.03; Shannon, p = 0.07), and not maternal BMI (Chao1, p = 0.49; Shannon, p = 0.54). At 12 months of age, infant BMI-for-age z-scores were only significantly related to maternal pre-pregnancy BMI (p = 0.01), and not human milk exposure (p = 0.53) or the infant gut microbiota (Chao1, p = 0.95; Shannon, p = 0.10; Bray-Curtis, p = 0.90; Sorensen, p = 1) [23].…”