Iron deficiency anaemia

Iron forms part of the molecule haemoglobin, which is found in red blood cells. Haemoglobin binds to oxygen from the lungs and unloads it to tissues around the body, such as muscles. Iron is also needed for many other reactions to occur in our bodies - for example, it assists enzymes that are involved in the production of bile acids.

Most of the iron absorbed from our diet is delivered to the bone marrow where red blood cells are formed. Any excess iron is stored either in the bone marrow or the liver or spleen.

Generally, our bodies contain about 2g to 4g of iron.

Iron levels in the body are maintained by altering how much iron is absorbed from the digestive system. This can change in certain circumstances. For example, during pregnancy - when iron requirements are higher - the digestive system increases how much iron is absorbed.

The human body can't excrete iron (unlike other minerals), so any excess amounts that collect in tissues can be harmful.

Dietary sources of iron

The most concentrated dietary sources of iron are red meat and offal such as liver. Smaller amounts of iron are also present in chicken and fish.

Iron found in meat is more easily absorbed by our bodies and is sometimes referred to as 'haem iron'.

Iron present in non-meat sources, such as cereals and vegetables, is called non-haem iron, and isn't as easily absorbed. Some foods have iron added to them (fortified) such as bread and breakfast cereals. Foods containing non-haem iron include:

• Green leafy vegetables such as watercress and spinach
• Pulses
• Soybean flour
• Dried fruit, such as figs and apricots
• Nuts
• Whole grains, such as brown rice

The good news is you can enhance your absorption of non-haem iron by making a few simple changes to your diet.

Minimise your risk of iron deficiency by choosing foods that are rich sources of haem iron. Enhance your absorption of non-haem sources by including foods rich in vitamin C, such as citrus fruits, and avoiding tea and coffee at meal times, because compounds in these drinks inhibit absorption of non-haem iron.

How to boost iron intake

What's the recommended iron intake?

Between age 11 and 50, men need 8.7mg of iron a day and women need 14.8mg a day. (Women over 50 require 8.7mg.) These levels meet the needs of most of the UK population.

In the UK, the National Diet and Nutrition Survey (NDNS) showed that in all adults (aged 19 to 64), the average intake of iron was 13.2mg a day in men and 10mg a day in women.

When broken down by age group, the survey found the youngest group of both men and women (aged 19 to 24) had the lowest intake of iron.

The survey also found most adults' dietary iron comes from non-haem sources. Nearly half comes from cereal products, such as breakfast cereals and white bread made from flour fortified with iron, about 10 per cent comes from vegetables and only a fifth comes from meat and meat products.

Iron deficiency anaemia

Lack of iron in the diet eventually results in iron deficiency anaemia. Symptoms include feeling tired or breathless, experiencing poor concentration and looking extremely pale. In children it can also affect mental and physical development.

Some groups are more vulnerable than others, including:

• Infants over the age of six months, especially if there are problems with weaning on to foods that provide iron
• Menstruating women, especially teenage girls who are still growing
• Women who are pregnant and have low iron stores at the start of pregnancy
• Vegetarians and vegans
• People with conditions that affect absorption of food - for example, inflammatory bowel disease

A blood test can be used to determine whether an individual has low iron stores, which might indicate the early stages of iron deficiency. Clinical anaemia is diagnosed when blood haemoglobin levels fall below a certain level (13g/dl for men and 12g/dl for women).

Correcting iron deficiency anaemia solely by increasing dietary iron would take a very long time, possibly years. Iron supplements are usually required, but a good diet is important to prevent or reduce the risk of developing iron deficiency anaemia.