Nutrition during pregnancy and infancy is crucial for normal brain development, as it supports neurodevelopmental processes such as neuron proliferation, myelination, and synapse formation. However, the long-term impact of early nutrient deficiencies on cognitive and socioemotional development is complex and influenced by factors such as the child's environment, the timing and severity of the deficiency, and the possibility of recovery. Severe acute malnutrition, chronic undernutrition, iron deficiency, and iodine deficiency are known to impair brain development. While strategies like salt iodization and micronutrient powders have shown promise, their direct impact on brain development remains unclear. Other interventions, such as iron and essential fatty acid supplementation, require further research. Environmental stimulation, timing of nutrient deprivation, and the degree of deficiency all play roles in determining the extent of cognitive deficits. For example, children with low socioeconomic status and poor environmental stimulation may be more vulnerable to the effects of undernutrition. Conversely, enriched environments can mitigate some of these effects. The timing of nutrient deprivation is also critical, as certain neurodevelopmental processes occur during specific periods of gestation and infancy. For instance, myelination of the brainstem auditory pathway is crucial in the third trimester and early infancy, and supplementation with docosahexaenoic acid (DHA) during this period may improve myelination. The possibility of recovery from early undernutrition is also important. Some studies suggest that improved nutrition, enhanced sensory and social interactions, and enriched environments can help recover cognitive abilities. However, the effectiveness of these interventions varies, and long-term follow-up studies are needed to determine their impact. Additionally, the selection of assessment tools and the age of assessment can influence the detection of nutritional effects. For example, cognitive deficits may not be apparent immediately but may manifest later in life. Human studies from low- and middle-income countries show mixed results, with some indicating that early undernutrition is associated with lower IQ, cognitive function, and school achievement. However, the effects can be mitigated through interventions such as food and protein/energy supplementation, breastfeeding, and essential fatty acid intake. Breastfeeding is associated with better cognitive development, particularly in low- and middle-income countries, where it is more common. Essential fatty acids, such as DHA and arachidonic acid, are important for brain development, but their effects on cognitive outcomes are not always clear. Micronutrient deficiencies, including iron, iodine, and zinc, are also linked to impaired brain development. Iron deficiency anemia during infancy is associated with poor cognitive and motor development, while iodine deficiency can lead to cretinism, a condition characterized by severe mental and physical impairments. Zinc deficiency may affect cognitive and motor development, but the evidence is mixed. Overall, adequate nutrition during pregnancy and infancy is essential for optimal brain development, and interventions should be tailored to the specific needs of vulnerable populations.Nutrition during pregnancy and infancy is crucial for normal brain development, as it supports neurodevelopmental processes such as neuron proliferation, myelination, and synapse formation. However, the long-term impact of early nutrient deficiencies on cognitive and socioemotional development is complex and influenced by factors such as the child's environment, the timing and severity of the deficiency, and the possibility of recovery. Severe acute malnutrition, chronic undernutrition, iron deficiency, and iodine deficiency are known to impair brain development. While strategies like salt iodization and micronutrient powders have shown promise, their direct impact on brain development remains unclear. Other interventions, such as iron and essential fatty acid supplementation, require further research. Environmental stimulation, timing of nutrient deprivation, and the degree of deficiency all play roles in determining the extent of cognitive deficits. For example, children with low socioeconomic status and poor environmental stimulation may be more vulnerable to the effects of undernutrition. Conversely, enriched environments can mitigate some of these effects. The timing of nutrient deprivation is also critical, as certain neurodevelopmental processes occur during specific periods of gestation and infancy. For instance, myelination of the brainstem auditory pathway is crucial in the third trimester and early infancy, and supplementation with docosahexaenoic acid (DHA) during this period may improve myelination. The possibility of recovery from early undernutrition is also important. Some studies suggest that improved nutrition, enhanced sensory and social interactions, and enriched environments can help recover cognitive abilities. However, the effectiveness of these interventions varies, and long-term follow-up studies are needed to determine their impact. Additionally, the selection of assessment tools and the age of assessment can influence the detection of nutritional effects. For example, cognitive deficits may not be apparent immediately but may manifest later in life. Human studies from low- and middle-income countries show mixed results, with some indicating that early undernutrition is associated with lower IQ, cognitive function, and school achievement. However, the effects can be mitigated through interventions such as food and protein/energy supplementation, breastfeeding, and essential fatty acid intake. Breastfeeding is associated with better cognitive development, particularly in low- and middle-income countries, where it is more common. Essential fatty acids, such as DHA and arachidonic acid, are important for brain development, but their effects on cognitive outcomes are not always clear. Micronutrient deficiencies, including iron, iodine, and zinc, are also linked to impaired brain development. Iron deficiency anemia during infancy is associated with poor cognitive and motor development, while iodine deficiency can lead to cretinism, a condition characterized by severe mental and physical impairments. Zinc deficiency may affect cognitive and motor development, but the evidence is mixed. Overall, adequate nutrition during pregnancy and infancy is essential for optimal brain development, and interventions should be tailored to the specific needs of vulnerable populations.