The confusing story of iron and brain development

Kellogs has been running a commercial recently claiming health benefits for their cereal based on its iron and calcium content.
On their website they make the following claims:
Iron supports your child’s growing brain1, energy levels and healthy growth. And breakfast cereals are the leading contributor of iron to children’s diets8-9.

The claim that kids need iron for healthy brain development is one that is massively repeated. In fact, cookbooks and food for children seem almost obsessed with iron content and its need for healthy brain development. Having never seen this from an actual reputable source, I have never been too convinced though.
So what's the evidence on it. Well truthfully, its a mess.

Iron certainly appears to be very important for brain development, particularly in infants. In early life, iron deficiency results in changes in brain formation, metabolism and a decline in overall functioning of certain sections of the brain 1. The result of early deficiency appears to be large deficitis in cognitive development and behavioural problems 2. This effect is sustained and a study on children who required iron supplementation ten years earlier found cognitive issues ranging from maths and writing through to motor functioning and memory recall. These children had often had difficulty in school including repeating grades and had mental health issues, social problems and attention problems 3.
However there are two large issues, first of all a causal connection has not been clearly established. Many iron deficient children are from low socio-economic backgrounds which makes causation difficult to establish 4. Iron supplementation does not reverse the effects of iron deficiency and preventative programs in developed countries have not been beneficial, these two factors contribute to the difficulty in establishing causation 4.
Secondly, most of the evidence on iron on brain development in humans relies on children who were clearly deficient and usually severely anaemic. There is a wide range of 'non-deficient' levels of iron in children and as iron is prioritised to red blood cells over the brain it is possible for there to be brain iron deficiency even with a normal iron level 5. There is little evidence on the effect of iron on brain development in non-anaemic children.
Also important is the fact that the biggest effect of iron on brain development is during gestation 6, immediately postnatally 5 and from 6 to 12 months of age. The effects of iron deficiency at this stage is considered to be irreversible even with supplementation, yet determining iron deficiency and iron stores in the first two stages is difficult in humans.
The net result of all this is a complicated picture but that overall iron deficiency does appear to have a significant impact on brain development. So what can you do to protect your child? What's effective and what isn't?

Pregnancy multivitamins
 Iron deficiency in pregnant women is common 6 and it has been suggested that the biggest issue is depleted iron stores in the infant due to poor iron levels in the mother 7. For this reason, routine iron supplementation is recommended for women living in areas where anaemia is common, however the situation for pregnant women from other areas is less clear and the world health organisation is waiting on the outcomes of further research prior to making any recommendations  8.
Pregnant women should be aware that their daily iron requirements are significantly higher than what is required pre-pregnancy (27 mg/day compared to 18 mg/day) 9. However they are still achievable with a healthy balanced diet. Appropriate antenatal care can alert you to if an iron supplement.

Cord clamping
The World Health Organisation has recommended delayed cord clamping due to the increased iron status in the infant for up to six months  10.

Iron supplementation of breastfeeding babies
A study has shown that infants breastfed for the first 6-7 months had greater iron stores than those fed cow milk based formula 12. Although another study showed anaemia was more likely in infants breastfeeding at 8 months, it was not associated with low iron stores 11. Many claim that breastmilk is low in iron, however babies absorb more iron from breastfeeding than they do from being fed cow milk based formula 12. Based on the evidence to date, iron supplementation of breastfed infants is not considered necessary.

Iron fortified cereal
Most health agencies recommend that the first foods introduced at around 6 months are foods that are iron rich, including iron fortified cereals. A study of 9 month old infants however found despite 95% of parents feeding iron fortified cereals, this did not appear sufficient to increase iron stores 11.

Cows milk
A study from Canada found that low iron stores in 9 month old infants was associated with  being bottlefed cows milk 11. Cows milk is considered to interfere with iron absorption particularly in infants up to 12 months of age and is such should not be consumed 13. After this age cows milk will not affect iron absorption as long as consumption is less than 500mls a day and dietary iron intake is adequate 13.

Children iron supplementation
Dietary iron deficiency in children can rapidly deplete brain iron concentrations but iron supplementation can normalise iron level and reverse the effects on the brain 14, 15. The World Health Organisation suggests routine iron supplementation for children in countries where anaemia rates are above 20%. However the benefits of iron in developed countries where anaemia rates are low is less clear.
The recommended daily intake of iron by age is below and are reasonably easy to reach if you are feeding (and your child eats) a relatively balanced diet. Many breakfast cereals and breads are iron fortified. Other obvious iron rich foods obviously include meats (particularly red), eggs and legumes as well as children favourites peanut butter, sultanas and dried apricots 16.

RDI Iron mg/day
Infants 7 - 12 months: 11mg
Children 1 - 3 yrs: 9mg
Children 4 - 8 yrs: 10mg
Boys 9 - 13 yrs: 8mg
Boys 14 -18 yrs: 11mg
Girls 9 - 13 yrs: 8mg
Girls 14 - 18 yrs: 15mg


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