Iron Deficiency & The Breastfed Baby
Iron has many important functions to keep us healthy, such as carrying oxygen around the body via the blood stream.
Hence, iron deficiency is not something to take lightly. If left untreated, iron deficiency anaemia can result.
Iron deficiency anaemia is a condition where there are insufficient healthy red blood cells to supply enough oxygen to bodily tissues. This condition can lead to fatigue, weakness, poor appetite and a rapid heart rate.
Iron deficiency in infancy has been shown to have a negative effect on emotions, learning ability, memory etc.
We know that infant formulas are fortified with iron, but what about exclusively breastfed babies – are they at risk of iron deficiency?
Breastfeeding Is The Biological Norm
Many papers written about breastfeeding and iron make claims such as ‘breastmilk is low in iron’.
However, since breastmilk is the normal food for human babies, what is or isn’t in other infant milks should be compared to breastmilk. Hence, breastmilk is not low in iron. Formula is however high in iron.
So, are exclusively breastfed babies at risk of iron deficiency?
Iron In Breastmilk Is Very Bioavailable
When we talk about something being bioavailable, it means the degree to which nutrients in food can be absorbed and utilised in the body.
About 70% of the iron in breastmilk is absorbed by a baby, whereas, only about 30% of the iron from cows’ milk and about 10% of the iron from formula is absorbed.
This high bioavailability of iron in breastmilk is due to several factors found in breastmilk, such as the iron binding protein in breastmilk, which is called lactoferrin.
Breastfed Babies Can Self-Regulate Their Iron Stores
Research shows that if breastfed babies have low iron stores (are iron deficient) they can upregulate their iron absorption from breastmilk, and hence increase their iron stores.
Research also shows that breastfed babies 6 months of age or younger cannot downregulate iron absorption from breastmilk in response to having increased iron stores (due to being supplemented with iron). This means they are at risk of being over-supplemented with iron. This research also shows that by 9 months of age, babies can down-regulate iron absorption from breastmilk in the situation where their stores are high.
Since breastfed babies can self-regulate their iron stores, giving iron sufficient breastfed babies (who are 6 months or less) iron supplementation may overload them with iron and this may be dangerous.
How could too much iron be bad for babies?
You Can Have Too Much Of A Good Thing
Potentially harmful bacteria thrive on free iron in the gut. This is why the iron in breastmilk is bound to the iron-binding protein (lactoferrin) so that it’s not free for potentially harmful bacteria to use it.
However, too much iron given to a baby in the first 6 months may promote the growth of pathogenic, iron-loving bacteria in the gut. This may disrupt the normal microflora of a breastfed baby’s gut.
Too much iron can also interfere with zinc absorption and sometimes cause digestive upsets in babies (eg diarrhoea).
There Are Risk Factors For Being Born Iron Deficient
Risk factors for a baby being born iron deficient include:
- Intrauterine growth restriction
- Maternal smoking during pregnancy
- Poorly-controlled gestational diabetes
- Prematurity. This is because most of the iron a foetus accumulates happens in the third trimester
Healthy Full-term Exclusively Breastfed Babies Are At Very Low Risk Of Iron Deficiency
Babies without prenatal risk factors (and particularly if their cords are clamped once it stops pulsating) are usually born with maximal iron stores. Being born with maximal iron stores means babies have enough stored iron until appropriate solid foods (which include those rich in iron) are introduced around 6 months.
Exclusively breastfed babies who are born healthy and at full term are at very low risk (only 3% in the first 6 months) of being iron deficient.
In most cases, healthy full-term exclusively breastfed babies have sufficient iron stores for at least 6 months. Giving supplemental iron to a baby under 6 months of age may be harmful. From around 6 months, appropriate solid foods (including those rich in iron) can and should be introduced, which means their iron stores continue to be sufficient.