angiogenesis . 6 As a cofactor of superoxide dismutase ( SOD ), it is involved in reducing and preventing oxidative damage to cell membranes and lipid peroxidation . 6 Copper also promotes the function of free radical scavengers such as metallothionein and glutathione . 6 As a cofactor of tyrosinase , it is involved in the synthesis of the skin pigment melanin . 6
Iodine
Iodine deficiency remains the most common cause of preventable mental impairment worldwide . 10 Iodine is involved in metabolic regulation , 9 , 11-13 production of thyroid hormones 9 , 12 , 14 ( triiodothyronine [ T3 ] and tetraiodothyronine [ T4 ]), 15 thyroid hormone regulation , 8 neural differentiation , 11 motor function , 16 mental development , 11 and cognitive function . 16 Iodine is required for normal growth and development , 11 neurodevelopment during pregnancy , 9 and somatic growth . 16 The maternal requirement for iodine is elevated during pregnancy . 13 Iodine deficiency during pregnancy can lead to cerebral dysfunction . 8
Some of the symptoms of iodine deficiency include impaired mental function , reduced work efficiency and capacity , decreased cognitive ability , impaired neurological development , and delayed physical development . 14 Iodine deficiency in children has many other manifestations , including subclinical hypothyroidism associated with a more atherogenic lipid profile that may be associated with increased cardiovascular disease risk . 14 Research has found that moderate to severe iodine deficiency is associated with a reduction in mean intelligence quotient ( IQ ) scores of around 13.5 points . 14 In populations where moderate iodine deficiency is common , there may be an increased prevalence of hypothyroidism , hyperthyroidism , and multinodular toxic goitre . 13 In populations where excessive iodine intake is common , there may be an elevated prevalence of hypothyroidism and autoimmune thyroid diseases ( including Graves disease ). 13
Iron
Iron is bound to transferrin and ferritin in the plasma and to iron-binding proteins in cells . 17 Iron plays a versatile role in biological systems . It plays a significant role in the production of haemoglobin and red blood cells . 9 Iron is an electron donor and acceptor . 18 It is required for energy metabolism . 8 Iron is included within the porphyrin ring structure of haem enzymes , for example , the family of cytochromes required for cellular energy production . Cytochromes serve as electron carriers during the synthesis of adenosine triphosphate ( ATP ) in the electron transport chain . 17 Iron is known to be critical for neuron development , neuronal differentiation and proliferation 17 and is involved in the synthesis of neurotransmitters 8 and myelin , 8 synaptic function , 17 and is critical during the development of the foetus . 8 Iron competes with heavy metals for uptake and can protect the body from the toxic effects of heavy metals . 18
Some of the symptoms of iron deficiency include iron deficiency anaemia , 8 fatigue , 17 low resistance to exertion , 17 rapid fatigue when exercising , 8 weakness , 17 impaired aerobic capacity , 17 and decreased work efficiency and working capacity . 17 Iron deficiency , with or without anaemia ,
impairs muscle function and limits work capacity . 19 Iron deficiency affects neural processes such as myelination , dendritic branching , and neural plasticity . 17 Symptoms associated with iron deficiency can be related to low oxygen delivery to body tissues and decreased activity of iron-containing enzymes . 17 Iron deficiency in early life may produce irreversible neural changes when neurogenesis and differentiation of brain regions occur . 17 Observational studies have shown associations between iron deficiency in children and poor motor and cognitive development outcomes . 17 Research also indicates that infants who are anaemic have poorer cognitive capacities , impaired school achievement , and increased behavioural difficulties . 17
Something to note is that excess iron may be toxic to cells . This is because iron can promote the generation of free radicals via the Fenton ’ s reaction . This is where iron reacts with hydrogen peroxide , producing hydroxyl radicals , with potentially highly detrimental effects . 17 The pro-oxidative action of iron is limited in normal physiological conditions by the very tight regulation of iron metabolism via homeostasis , which prevents iron overload . 17
82 | vol28 | no2 | JATMS