Iron

Iron is needed for the formation of haemoglobin in red blood cells, which transports oxygen around the body. Iron is also required in myoglobin in the muscle cells and also in many cell enzymes.

Iron needs are greatest in women of child-bearing age, as iron lost through menstruation must be replaced.

Iron absorption

The main factor controlling absorption is the amount of iron stores in the body. Iron absorption is also controlled by the requirements of a particular individual and the amount of iron consumed. The presence of particular components in foods can enhance or inhibit the absorption of iron.

Iron sources

There are two types of iron sources. Haem iron is from meat, poultry and fish and is typically well absorbed. Non-haem iron is found primarily in plant based foods, iron supplements and is the type of iron used for fortification of foods, e.g. cereals. Non-haem iron is not as well absorbed

Combining non-haem iron with meats and good sources of Vitamin C improves the absorption of non-haem iron. Components which inhibit the absorption of non-haem iron are polyphenols (in tea, coffee, and particular vegetables) and phytates (in unrefined cereals, nuts and legumes.) These components bind to the iron making it harder, or impossible, for the iron to be processed and absorbed and thus making it unavailable for use in the body.

Recommended daily intakes (RDI) for iron (g/day)

 

Age (years)

 

19-54 years

54+ years

Women

12-16

5-7

Men

7

7


The most recent National Nutrition Survey indicated that low iron stores and iron-deficiency anaemia mainly affected women aged between 15 and 44 years. Overall males are not affected by low iron stores.

Iron deficiency

A lack of iron in the diet, leads to low iron stores in the body and eventually to iron-deficiency anaemia. As so much of the body’s iron is in the blood, losses are greatest whenever blood is lost. Symptoms of iron deficiency are usually a lack of energy, reduced resistance to colds and inability to concentrate. Either iron supplements or a change in food choices may be required to increase iron stores and cure iron-deficiency anaemia. The use of supplements should be discussed with a health professional.

Food sources of iron

To maintain iron stores, eat plenty of iron-rich foods such as red meat, liver, fish and chicken, or if vegetarian eat plenty of iron rich plant sources, such as beans and lentils. Breakfast cereals and vegetables are important sources of iron in the New Zealand diet. To optimise iron intake, include foods rich in Vitamin C when eating iron-rich foods. However it is best to avoid tea and coffee at mealtimes as components of these drinks bind to iron and prevent the absorption of iron into the body.