Iron Needs and Sources

Dr. Parang Mehta, MD.

It is well known that iron is needed to form blood, but did you know that iron is necessary for the development of intelligence in children?  It's true.  Iron deficiency in childhood (with or without accompanying anemia) adversely affect the development of the brain, and this effect may not be completely correctable later.

Iron in the body

The best known purpose of iron in the body is probably in the blood.  Iron is essential for the formation of hemoglobin, a protein in the red blood cells that carries oxygen to the various organs.  Without enough iron, a child's body cannot make enough hemoglobin, and a condition called anemia occurs.  The child is pale, dull, and lethargic.  Appetite and activity also suffer in iron deficiency.

Iron is essential for many enzyme systems all over the body. Brain development in early life is also iron dependent

Iron is also an essential component of many enzyme systems that are needed for smooth functioning of the body.  Muscle also contains a protein, myoglobin, that requires iron.  All these systems do not function optimally in iron deficiency, and children start feeling weak and tired even before anemia becomes obvious.

In the body, iron is stored in the liver, bone marrow, spleen, and kidney.  It is absorbed from iron containing food in the diet, and the proportion of iron absorbed depends on the body's need.  The absorption is helped by gastric juices and ascorbic acid (Vitamin C), and hindered by dietary fiber, phytates (present in most grains), and malabsorption.

Iron in babies

Babies are born with a small store of iron in the liver and bone marrow, obtained from the mother.  Breast milk contains small amounts of iron only, but this is very well absorbed.  A breast fed baby's iron status is well maintained until about six months of age, when extra iron is required.

Very little iron is obtainable from food, especially in vegetarians

Most foods given to babies, especially in vegetarian families, are grain based, and contain small amounts of iron.  Rice, maize, and wheat contain small amounts of iron only.  This iron is not well absorbed, because of phytates present in the grain, which retard iron absorption.  Considering that babies need 6-10 mg iron a day, it is no surprise that many of them become iron deficient and suffer anemia and other adverse effects.

Iron deficiency

Iron deficiency develops in children when they are given only breast feeding beyond the age of 6 months.  Children fed on cow's milk become deficient sooner.  Adding grains does not help, and these children become anemic, and show the other signs of iron deficiency -- poor appetite, poor growth, slower development, lethargy, etc.  Perhaps most important is the effect on the growing brain, which occurs even before anemia becomes obvious.  The deficits may be lifelong.

Older children are prone to iron deficiency, too.  Most children do not like green vegetables, and unless the diet contains enough other sources of iron, deficiency can occur.  Apart from dietary factors, infections like worms and malaria can also lead to iron deficiency.  Slow, hidden, blood loss from the intestines or elsewhere can sometimes be a cause of iron deficiency.

All anemia is not caused by iron deficiency, and if a child looks pale, a doctor's evaluation is necessary.

Iron Content of Various Foods

Breast milk 0.3-0.5 mg/L
Cow's milk 1-1.5 mg/L
Rice 1 mg/100 gm
Wheat 0.8 mg/100 gm
Maize 0.8 mg/100 gm

 

Prevention of iron deficiency

Iron is available in a lot of foods (see sidebar), but for vegetarians, the options are limited.  Children often do not like green leafy vegetables, and do not consume enough quantities to ward off iron deficiency.

An option here is iron supplementation -- either the use of cereals and infant formulas containing added iron, or the administration of iron syrup or drops.  Normal babies who are breastfed require additional iron after about six months.  Babies born prematurely, or those on cow's milk feeding, need additional iron earlier.  In America, the use of iron fortified infant formulas has reduced the occurrence of iron deficiency and anemia from about 30% to less than 5% of children.

 

Last Revision: May 14, 2020