Iron is an important trace mineral required for the correct function of the haemoglobin molecule. However, as well as this important function, iron is also required as a cofactor in a number of enzymes including the hydroxylase enzymes used by the brain to synthesise certain neurotransmitters. Iron deficiency can therefore affect the formation of the catecholamine neurotransmitters, as well as serotonin. This role as a cofactor to hydroxylase enzymes, as well as its requirement for the correct transport of oxygen, may explain the detrimental cognitive effects of iron deficiency. For example, iron deficiency is related to an inability to concentrate and may be cause of certain antisocial and disruptive behaviors. Worldwide, iron deficiency is the most common form of nutritional deficiency, and women are at particular risk of iron deficiency compared to men. It is therefore likely that the cognitive effects of iron deficiency may be relatively more common in women compared to men.
Iron deficiency can have significant detrimental cognitive effects. These effects can be present despite the lack of anaemia. The cognitive effects of poor iron status are not fully understood, and the symptoms that may be experienced are likely vague and difficult to clinically identify. As poor iron status is widespread, it is likely that many people unknowingly suffer from these sorts of idiosyncratic effects. Taking a good quality multivitamin and mineral supplement, and consuming bioavailable forms of iron, such as is present in meat and fish, is therefore recommended. Vegetarians should consume an iron supplement containing iron as an amino acid chelate to ensure a highly absorbable form of iron in the absence of animal flesh in the diet. Pants foods can contain iron, but it may not be bioavailable.
A number of studies have investigated the cognitive effects of iron deficiency in women. For example, in one study researchers investigated the associations between iron status and cognitive ability in a number of healthy women without anaemia. The results showed that a better iron status in the women was associated with better attention (as measured by reaction time), better inhibitory control (as measured by lower variability in reaction time) and better planning ability (as measured by less time required to plan and smaller planning time increases with increasing task difficulty). However, working memory was inversely associated with better iron status, and the authors suggest that this may relate to the interference between the hippocampus and the frontal cortex. Iron surplus was associated with an increase in reaction times. Although these results do not show a cause and effect, they are interesting all the same, and support the contention that changes to iron status may have significant cognitive effects in women.
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