The physiology of poverty: gut microbiome and pathways to child stunting

The causes of childhood stunting remain debated, with emerging evidence highlighting the complexity of poverty-related mechanisms. While nutrition, healthcare and sanitation have traditionally been viewed as the primary drivers of stunting, new research highlights the physiological mediators linking poverty to impaired growth. Chronic exposure to unsanitary environments may lead to environmental enteric dysfunction, a subclinical gut condition that may impair the development of the gut microbiome. Stunted children frequently exhibit an immature and dysbiotic gut microbiome, which is linked to higher levels of gut inflammation, reduced nutrient assimilation and increased susceptibility to infections. Here, we examine how poverty-related factors, including poor diet and hygiene, affect gut health and early neurodevelopment, with a particular focus on the gut-brain axis. Understanding this 'physiology of poverty' reveals that effective interventions must extend beyond food provision to integrate improvements in water, sanitation, hygiene (WASH) and microbiome support (e.g. via probiotics or prebiotics). A holistic strategy targeting environmental and biological factors in early life is critical to disrupting the intergenerational cycle of stunting and poverty. We identify key evidence gaps and stress the need for multidisciplinary, context-specific approaches to mitigate stunting's long-term association with health and human capital. This article is part of the theme issue 'Biological, biomedical and environmental drivers of stunting'.