Nutritional iron and childhood intellect

Abstract

Iron deficiency is the most prevalent micronutrient malnutrition globally. It is known to affect both children and adults especially pregnant women largely in the developing countries. Iron is not only important for haemoglobin synthesis but also for normal brain development. In the body, the ferrous formis converted into ferritin which is the active molecule. The brain is especially sensitive to variation in iron availability, in part due to the high metabolic demands of the brain that are supported by iron. Iron is necessary for basic neuronal processes such as myelination, neurotransmitter production, and energy metabolism. With neuroimaging support, Globus pallidus, caudate nucleus, putamen, substantia nigra and the hippocampus have been of primary interest in studies of iron because they show robust and quantifiable levels of iron content. Furthermore, these regions are central to cognitive abilities that develop across childhood and adolescence, such as processing speed, cognitive-motor control, reward-processing, and working memory function. The hippocampus per se plays important roles in the consolidation of information from short-term memory to long- term memory, and in spatial memory that enables navigation. Low iron levels in pregnant women correlates with low ferritin levels in their foetus and newborns whereby several studies have clearly demonstrated the effect of iron on developmental milestone regarding cognition and behaviour. Iron deficiency early in life, therefore, confers irreversible brain dysfunction even after complete brain iron repletion. Iron therapy and replenishment of brain ferritin may revert to normal cognitive functions in adults and adolescents but not in children. Rich sources of iron are meat, liver, dark leafy green vegetables, fish, poultry, peas and beans. Pregnant women require routine daily iron supplement; lactating woman and all children should be fed balanced diet. Special iron supplement should be provided for preterm and small-for-gestational-age infants from the age of two months.