Iron deficiency anaemia in infants
Dr Justine Dempsey gives a guide to infants’ needs for iron and when GPs should suspect anaemia
Dr Justine Dempsey gives a guide to infants' needs for iron and when GPs should suspect anaemia
The WHO definition of iron deficiency anaemia is haemoglobin of less than 110g/l for children age one to two and less than 112g/l in children aged three to five years1.
Iron deficiency anaemia is one of the commonest nutritional deficiencies in the UK. It is often seen in pre-school children, Asian children living in Britain and deprived inner-city areas.
The main cause of iron deficiency anaemia is dietary, from poor food intake, faddy eating or restrictive diets, although there are other causes.
Symptoms can include:
• reduced physical activity
• susceptibility to infections
• delayed psychomotor development.
There is contradictory evidence in the literature as to whether any delay in psychomotor development is reversible2. These symptoms of iron deficiency anaemia in themselves can cause a decreased dietary intake, further compounding the problem.
Iron stores in the newborn and onward
The majority of an infant's iron store is laid down in the third trimester of pregnancy. Preterm infants have lower iron stores at birth and increased requirements because of their faster rate of growth.
The specific needs of preterm infants will not be addressed here but a comprehensive review and recommendations of preterm requirements has been written3.
The full-term infant has adequate iron stores for the first six months of life. Breast milk has a relatively low iron content, but the iron is present in a readily bioavailable form called lactoferrin and this is well absorbed.
After the infant is six months of age, breast milk alone does not have sufficient amounts of iron to keep up with the infant's increasing requirements. Iron must be provided by other dietary sources during weaning or additional supplementation at this stage.
Between the age of four to six months and 10 to 12 months, iron requirements double.
This is a period of rapid growth and an increased intake of iron is needed to maintain the infant's haemoglobin concentration.
Iron in infant and follow-on formulas
Infant formulas are fortified with iron, although absorption from formula milk is not as efficient as from breast milk. It is not clear what the absorption rate of iron from formula milk is. To compensate for this, iron and other vitamins and minerals are present in higher amounts in formula milk than breast milk.
Follow-on formulas are available on the market and can be used in infants aged six months and onwards in the UK. These contain higher levels of iron than standard infant formula. They can be particularly useful in the picky eater, as a daily intake of 500ml of follow-on formula milk can provide all the infant's iron requirements.
It can be useful to continue the use of follow-on formula in children where dietary intake may be of concern.
Full cream cow's milk can be introduced as the main milk drink after the age of 12 months.
Cow's milk is a poor source of iron. It contains only 0.05mg per 100ml compared with follow-on formula, which contains approximately 1.2mg per 100ml.
The calcium and phosphoprotein compounds present in cow's milk bind to dietary iron and prevent it being fully absorbed.
Early introduction of cow's milk as a main drink before the age of one year and large intakes of cow's milk have been linked with the development of iron deficiency anaemia.
In some cultures there is an emphasis on milk as a staple food, which may be offered in the place of meals. In some families milk consumption is encouraged by adding rusk, baby rice or sugar to feeding bottles. This is something that needs to be discouraged and the reasoning behind limiting cow's milk consumption needs to be explained to families.
The prolonged use of bottle feeding can encourage excessive milk intake. Children should be introduced to a beaker from the age of six months and encouraged to drink from a cup by 12 months to try to reduce their consumption of milk.
Some children derive a large amount of their daily calorie intake from milk or squash and therefore have a limited appetite for solid foods.
It is common in this group to see children with a bottle that seems to be almost permanently in their hands or mouths. These children are at high risk of iron deficiency anaemia.
Most foods used during the early weaning period (four to six months) are generally poor sources of iron – for example, baby rice, most fruit and vegetables.
Weaning is an area that may need to be looked at in light of the Department of Health recommendations that promote weaning from the age of six months. More research will need to be done on the age solids are introduced and when iron-rich solids should be incorporated in infant's diets.
Does weaning advice need to be reviewed and iron-rich foods offered sooner in the initial stages of weaning?
As we know that the full-term infant is born with only enough iron stores for the first six months of life, it may be necessary to review the weaning literature in light of the new recommendations.
Dr Justine Dempsey is head of nutrition and dietetic services at Northwick Park and St Mark's Hospital, London
This article is an extract from Practical Paediatric Problems in Primary Care, published by Oxford University Press, edited by Mr Michael Bannon and Professor Yvonne Carter. www.oup.co.uk. ISBN 978-0-19-852922-4