The Human Microbiome and Child Growth – First 1000 Days and Beyond

Delayed or immature assembly of the gut microbiota underlies severe acute malnutrition in children.

The gut microbiota affects the somatotropic axis through regulation of IGF-1 and growth hormone production, thereby affecting growth.

There is emerging knowledge of the influence of prenatal microbial communities on fetal and postnatal growth.

The gut microbiota plays an influential role in inflammation and enteropathy, which may be linked to growth faltering.

The first 1000 days provides a window of opportunity for modulating the microbiota through interventions such as diet, antibiotics, probiotics, prebiotics, or fecal microbiota transplantation to promote healthy growth and development.

The assembly of microbial communities within the gastrointestinal tract during early life plays a critical role in immune, endocrine, metabolic, and other host developmental pathways. Environmental insults during this period, such as food insecurity and infections, can disrupt this optimal microbial succession, which may contribute to lifelong and intergenerational deficits in growth and development. Here, we review the human microbiome in the first 1000 days – referring to the period from conception to 2 years of age – and using a developmental model, we examine the role of early microbial succession in growth and development. We propose that an ‘undernourished’ microbiome is intergenerational, thereby perpetuating growth impairments into successive generations. We also identify and discuss the intertwining host–microbe–environment interactions occurring prenatally and during early infancy, which may impair the trajectories of healthy growth and development, and explore their potential as novel microbial targets for intervention.