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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
Children1-3

9
4-8

10
9-13

8

Girls14-18

15
Boys14-18

11
Men19-70+

8
Women19-50

18
Over 50

8
Pregnant women

14-50

27
Breastfeeding women

14-18

10
19-50

9

Source: Iron | NRV

Who needs more and why?

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

Which foods contain iron?

There are two types of iron in food: haem iron (absorbed very well) and non-haem iron (not absorbed very well).  Meat, poultry and seafood, contain both haem iron and non-haem iron. Plant foods, such as vegetables, cereals, beans and lentils, contain only non-haem iron so the iron in these foods is not absorbed as well by the body.

The best food sources of iron are:

  • beef and lamb (the redder the meat, the more iron there is in it)
  • shellfish e.g. mussels, oysters
  • chicken, fish

Other foods with iron are:

  • grains: porridge, oatmeal, iron-fortified breakfast cereals (eg, Weetbix) and wholegrain breads
  • vegetables: greens (spinach, silverbeet, lettuce), beans and peas, pumpkin and sweet potatoes
  • eggs
  • chickpeas, beans, lentils
  • some nuts

Haem 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

1 slice fried lamb liver

4
90g can salmon

2.1
1 grilled chicken breast (107g)

2
1 grilled lean pork loin chops (74g)

1.2
1 baked tarakihi fillet

0.8

 

Non-Haem Iron content of foods

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
½ cup cooked boiled 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?

  • 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.
  • To increase the absorption of non-haem iron try to have vitamin C-rich foods – such as kiwifruit, citrus fruits, orange and capsicums – at the same time. For example, topping with your breakfast cereal with kiwifruit will increase the iron absorbed from the cereal.
  • 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.
  • If you don’t eat meat and seafood, try to include foods that are rich in non-haem iron such as tofu, iron-fortified breakfast cereals and cooked beans and lentils every day.
  • 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:

  • not eating enough iron-rich foods
  • an increased need for iron, e.g. during pregnancy
  • iron 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 (a condition where a person’s body absorbs too much iron).

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 the absorption of other essential nutrients, such as zinc and calcium.

 

More info

  • Health Navigator: Iron

Last modified: March 10, 2022