Iron

We need iron to produce haemoglobin in our blood, which carries oxygen around our body. Our immune system also needs iron  to work well.

How much iron do we need?

 


Age (years)


RDI*
Iron (mg/day)
Infants 7-12 months 11
Children 1-3 9
  4-8 10
  9-13 8
Girls 14-18 15
Boys 14-18 11
Men 19-70+ 8
Women 19-50 18
  Over 50 8
Pregnant women 14-50 27
Breastfeeding women 14-18 10
  19-50 9
 *Recommended Daily Intake

Who needs more and why?

  1. Babies, children and teenagers because they are growing rapidly
  2. Girls and women who have periods, due to loss of blood each month
  3. Pregnant women who need enough iron for themselves and their growing baby.  This is particularly true towards the end of pregnancy when the baby is growing most rapidly.
  4. Athletes, particularly endurance runners

Which foods contain iron?

There are two types of iron in food: haem and non-haem iron.  Haem iron is only found in meat, chicken and fish, and is easily absorbed.  Non-haem iron is also found in plant foods, such as vegetables, cereals , beans and lentils, but is not absorbed as well by the body. 

Iron content of foods

Foods containing haem iron

Iron (mg)

1 grilled lean beef fillet steak (173g)

5.8

½ cup green mussels, marinated

7.5

2 grilled lean lamb leg steaks (116g)

4.0

1 slice fried lamb liver

4.0

90g can salmon 

2.1

1 grilled chicken breast (107g)

2.0

1 grilled lean pork loin chops (74g)

1.2

1 baked tarakihi fillet

0.8

 Foods containing non-haem iron

 Iron (mg)

100g tofu

5.4

1 cup porridge

1.3

1 Wheat biscuit

1.5

½ cup cooked red kidney beans

2.0

½ cup cooked boled lentils

1.2

½ cup fruity muesli

1.9

½ cup cooked chickpeas

1.6

1 cup boiled broccoli

0.9

½ cup baked beans

1.6

10 dates

1.3

1 cup boiled spinach

2.5

1 boiled egg

0.9

1 slice multigrain bread

0.7

 

How can I get enough iron?

  1. Lean red meat is the best source of easily-absorbed haem iron, so try to include it 3-4 times per week. Other meats (chicken, poultry, pork) and fish are also good sources of easy to absorb iron, so eat a variety of these to increase your iron intake.
  2. To increase the absorption of non-haem iron try to have vitamin C-rich  foods – such as kiwifruit, citrus fruits, orange juice and capsicums – at the same time. For example, a glass of orange juice with your breakfast cereal will increase the iron absorbed from the cereal.
  3. Combining haem foods with non-haem foods also increases the absorption of iron.  For example, adding lean meat to a salad sandwich increases the amount of iron absorbed from the bread and salad. 
  4. If you don’t eat meat and fish, try to include foods that are rich in non-haem iron such as tofu, iron-fortified breakfast cereals and cooked beans and lentils.
  5. Tea reduces the amount of iron absorbed by the body. Drink tea between meals, or wait at least ½ -1 hour after eating. 

Iron and blood levels

Low levels of blood haemoglobin are relatively common, particularly among those needing the most iron.  Too little iron in the blood can lead to paleness, tiredness and lethargy, making it harder to concentrate, and affecting our performance at school or work. Resistance to illness, such as infections, coughs and colds, is also weaker.  

Low blood levels can be caused by:

  1. not eating enough iron-rich foods
  2. an increased need for iron, e.g. during pregnancy
  3. iron being lost in the gut through conditions such as peptic ulcers, tumours or ulcerative colitis.

Having too much iron in the blood is also possible, but much less common.  It can be caused by taking iron supplements when not needed, a high alcohol intake, hepatitis or haemochromatosis.

If you are concerned about your blood levels of iron e.g. have heavy periods, are tired, weak, lightheaded or look pale, talk to your doctor about having a blood test. Iron supplements should only be taken under medical supervision, as unsupervised use of iron supplements can reduce absorption of other essential nutrients, such as zinc and calcium.

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