The Role of Nutrition in Brain Development: The Golden Opportunity of the “First 1000 Days”

Among the factors that influence early brain development, three stand out has having particularly profound effects: reduction of toxic stress and inflammation, presence of strong social support and secure attachment, and provision of optimal nutrition3.

This article focuses on the latter by first describing the important features of brain development in late fetal and early postnatal life, discussing basic principles by which nutrients regulate brain development during that time period, and presenting the human and pre-clinical evidence that underscores the importance of sufficiency of several key nutrients early in life in ensuring optimal brain development.

Brain Development in Late Fetal and Early Postnatal Life

Policy makers have recently placed a great deal of emphasis on the “first 1000 days” and “0–3” (years) as golden opportunities to influence child outcome. The first 1000 days correspond roughly to the time from conception through 2 years of age. However, a closer examination of the trajectory of anatomical and functional brain development combined with clinical and epidemiological studies of neurodevelopmental outcome suggests a slightly broader window extending to three years.1,3 Nevertheless, the same basic principles of brain development discussed below continue to apply.

The brain is not a homogeneous organ. Rather, it is comprised of multiple anatomical regions and processes (eg, myelination), each with unique developmental trajectories1. Many of these regions have developmental trajectories that begin and accelerate in fetal life or shortly after birth.

• For example, myelination abruptly increases at 32 weeks gestation and is most active in the first 2 postnatal years1.
• The monoamine neurotransmitter systems involved in mediating reward, affect, and mood begin their development pre-natally4, continuing at a brisk pace until at least age 3 years.
• The hippocampus, which is crucial for mediating recognition and spatial memory begins its rapid growth phase at approximately 32 weeks gestation, continuing for at least the first 18 postnatal months1,5.
• Even the prefrontal cortex, which orchestrates more complex processing behaviors, such as attention and multi-tasking, has the onset of its growth spurt in the first 6 postnatal months1,5.

Keeping brain areas on developmental trajectory is critical not only for promoting behaviors served by the individual regions, but also more importantly, to ensure time-coordinated development of brain areas that are designed to work together as circuits that mediate complex behaviors6.

Early life events, including nutritional deficiencies and toxic stress, can have differential effects on developing brain regions and processes based on the timing, dose, and duration of those events7. The importance of timing in particular should be underscored.8 

As noted, the timing of peak rates of development of the hippocampus and prefrontal cortex differ. The timing of an adverse environmental event that, for example, affects neuronal dendritic arborization will determine whether the hippocampus or the prefrontal cortex sustains greater damage and compromise of functional integrity. The earlier the insult, the more likely the hippocampus will be affected more than the prefrontal cortex. In a brain circuit that requires balanced hippocampal and prefrontal input (eg, the ventral tegmental area loop), such imbalance can result in significant behavioral pathology, such as schizophrenia6,9.

Neuroscientists and psychologists use terms such as “critical period” and “sensitive period” to describe time epochs of opportunity and vulnerability.

Critical periods are typically conceptualized as early-life epochs when alterations to brain structure or function by an environmental factor (eg, nutrition) result in irreversible long-term consequences10.

Sensitive periods imply an epoch when the brain (or brain region) is more vulnerable to environmental factors, including nutrient deficiencies, but when the effect is not necessarily deterministic10,11. The term “sensitive period” can also be used in a positive manner to describe times when the brain may be particularly receptive to positive nutritional or social stimulation.

Both concepts rely on the observation that the young, rapidly developing brain is more vulnerable than the older brain, but also retains a greater degree of plasticity (eg, recoverability). Over time, the distinction between critical and sensitive periods has become blurred as more research emerges. Although the distinction may become less meaningful, either concept emphasizes the need for pediatricians to focus on making sure the child is receiving adequate nutrition to promote normal brain development in a timely fashion12–14.

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