The negative impact of stunting and severe underweight on cognitive neurodevelopment of children is well documented; however, the effect of overweight/obesity is still unclear. The 2018 Global Nutrition Report reported that stunting and overweight concurrently affect 189 million children worldwide. As existing reviews discuss undernutrition and overweight/obesity separately, this scoping review aims to document the impact of mild/moderate and severe underweight, stunting, and overweight/obesity among children aged 0-60 months on their cognitive neurodevelopmental trajectories. Twenty-six articles were analysed to extract significant information from literature retrieved from PubMed and Cochrane databases published from 1 January 2009 to 31 October 2019. Length gain is associated with cognitive neurodevelopment in normo-nourished and stunted children aged under 24 months. Among stunted children, it seems that cognitive and neurodevelopmental deficits can potentially be recovered before 8 years of age, particularly in those whose nutritional status has improved. The impact of overweight/obesity on cognitive neurodevelopment appears to be limited to attention, gross motor skills and executive control. Parental education level, birth weight/length, breastfeeding duration, and sanitation level are some identifiable factors that modify the impact of undernutrition and overweight/obesity on cognitive and neurodevelopment. In conclusion, underweight, stunting and overweight/obesity have a significant impact on cognitive neurodevelopment. Multidimensional approaches with various stakeholders should address all issues simultaneously, such as improving sanitation levels, assuring parental job security and adequate social welfare, and providing access to adequate nutrients for catch-up growth among underweight or stunted children and to affordable healthy foods for those who are overweight/obese and from low socio-economic status.
Growth faltering under 5 years of age is unacceptably high worldwide, and even more children, while not stunted, fail to reach their growth potential. The time between conception and 2 years of age is critical for development. The period from 6 to 23 months, when complementary foods are introduced, coincides with a time when growth faltering and delayed neurocognitive developments are most common. Fortunately, this is also the period when diet exercises its greatest influence. Growing up in an adverse environment, with a deficient diet, as typically seen in low- and middle-income countries (LMICs), hampers growth and development of children and prevents them from realising their full developmental and economic future potential. Sufficient nutrient availability and utilisation are paramount to a child's growth and development trajectory, especially in the period after breastfeeding. This review highlights the importance of essential amino acids (EAAs) in early life for linear growth and, likely, neurocognitive development. The paper further discusses signalling through mammalian target of rapamycin complex 1 (mTORC1) as one of the main amino acid (AA)-sensing hubs and the master regulator of both growth and neurocognitive development. Children in LMICs, despite consuming sufficient total protein, do not meet their EAA requirements due to poor diet diversity and low-quality dietary protein. AA deficiencies in early life can cause reductions in linear growth and cognition. Ensuring AA adequacy in diets, particularly through inclusion of nutrient-dense animal source foods from 6 to 23 months, is strongly encouraged in LMICs in order to compensate for less than optimal growth during complementary feeding.