Review Paper Links Brain-Gut-Sleep Development in First 1,000 Days

By Allison Proffitt

May 7, 2026 | A new paper published in Nutrients outlines the connected development of the brain, gut, and sleep in the first 1,000 days of life—from conception to the second birthday. The review highlights a growing body of research linking maternal nutrition and health status during pregnancy directly to infant development, underscoring the need to better support women before, during, and after pregnancy.

The peer-reviewed paper (DOI: 10.3390/nu18030445), written by authors associated with SmartyPants Vitamins, University of Arizona, Icahn School of Medicine at Mount Sinai, reviews the literature for the nutrients critical to development of the brain and gut in the first 1,000 days of life and links that development to infant sleep. The authors flag gaps in our understanding of this window and highlight how we can better understand how early-life nutritional interventions can optimize neurodevelopmental outcomes

“Parents often hear that the first 1,000 days matter, but this research helps explain why,” said Devyani Chaturvedi, Senior Nutrition Scientist at SmartyPants Vitamins and first author on the paper. “This review helps explain why nutrition doesn’t just influence one aspect of development—it simultaneously affects brain growth, gut microbiome development, and sleep architecture. These systems interact continuously to shape lifelong health.”

Sleep Insights

The authors found that early development does not happen in silos: brain, gut, and sleep develop as interconnected systems, with sleep an active biological process that interacts with brain growth and gut health, not just a result. Sleep helps shape cognitive, language, and behavioral development early in life and is important to both pregnant mothers and their infants.

Pregnancy increases the body’s need for sleep, but common discomforts and pregnancy-related sleep disorders can make those extra hours hard to come by. The impacts of lost sleep are systemic.

“Sleep loss dysregulates the hypothalamic–pituitary–adrenal axis, elevating cortisol while diminishing melatonin, which is essential for reproductive hormone regulation and neurodevelopmental signaling. These neuroendocrine and microbial changes disrupt metabolic hormones such as ghrelin and leptin, impairing appetite control and insulin sensitivity, and collectively increase the risk of adverse pregnancy outcomes,” the authors write.

For children, sleep appears to be both influenced by and an influencer of the gut microbiome. “Disruptions in early microbial development have been associated with alterations in sleep–wake cycles, circadian rhythm consolidation, and behavioral outcomes,” the authors write. “Given that both sleep and gut health are critical during the early days, understanding their interplay may offer new insights into strategies for optimizing neurodevelopmental outcomes through microbiome-targeted interventions.”

Brain Development

The first 1,000 days are a known window of explosive brain grown. During this time, the brain displays remarkable plasticity, allowing for significant modification and refinement of synaptic connections. Various mechanisms can shape neural development and ultimately neurodevelopmental outcomes and we know that nutrition impacts these outcomes, particularly folic acid.

Gut Health

The infant gut microbiome develops rapidly during the first two years of life and plays a central role in neural signaling, immune system development, and sleep regulation, linking nutrition to both brain function and sleep patterns. It’s impacted by everything from maternal diet to mode of delivery to nutrition and antibiotic use in the first two years after birth and the impact of gut microbiome on the nervous system (both central and enteric) has been demonstrated in several rodent studies.

Nutrition

The authors argue that nutrition during the first 1000 days of life is the easiest way to impact the development of these interconnected systems.

“By treating nutrition as a shared resource for brain, gut, and sleep development, there are significant gains to be made in improving child health that may even extend into adulthood,” the authors contend. There is solid evidence for some nutrients and early-life outcomes, for example, DHA, Choline, and others. But the authors plead for further research including standardized recommendations for nutrients like omega-3 beyond six months of age and for biomarkers to detect early deficiencies of choline & vitamin B12.

“Understanding the science behind early development helps us better support families and healthcare providers,” added Chaturvedi in the same press release. “Investing in this research allows us to contribute to a deeper understanding of maternal and early-life health, ensuring our approach remains evidence-driven and clinically relevant.”