Anaemia occurs when there are too few red blood cells or not enough haemoglobin in the blood. Haemoglobin is an iron-containing compound found in the red blood cells, which transports oxygen around the body. The most common type of anaemia occurs when there isn't enough iron in the body.
About iron-deficiency anaemia
You need iron for many important processes inside your body, especially for making haemoglobin - the oxygen-carrying protein in your blood. Haemoglobin gives red blood cells their characteristic red colour and is necessary for the blood to pick up oxygen from the lungs and then carry it to every cell in your body.
Iron is absorbed from your food and drink in the intestines. It's carried in your blood to your bone marrow, where blood cells are produced. Here, the iron is combined with proteins to make haemoglobin. Any extra iron can be stored in your liver. Your body also recycles iron from old and worn out red blood cells to make new ones.
However, if you have a shortage of iron in your body, your bone marrow will make small red blood cells that don't contain enough haemoglobin. These red blood cells can't carry enough oxygen to your organs and tissues. This leads to the symptoms of anaemia.
Symptoms of iron-deficiency anaemia
The common symptoms of iron-deficiency anaemia include:
- feeling breathless after little exercise
- feeling tired
- heart palpitations (the sensation of your heart beating abnormally fast or with an irregular rhythm)
- looking pale.
Less common symptoms can include:
- tinnitus (ringing in your ears)
- altered sense of taste
- brittle nails or 'spoon nails' where the middles of your nails are pushed inwards and the edges are raised
- soreness at the edges of your mouth
- poor concentration.
These symptoms aren't always due to iron-deficiency anaemia but if you have them, it's a good idea to talk to your GP.
What can cause iron-deficiency anaemia?
Loss of blood
Small amounts of iron are lost from your body in urine, faeces and dead skin cells. Much larger amounts are lost through blood, especially in cases of:
- heavy menstrual losses or blood loss associated with an injury or after an operation
- stomach or bowel (intestine) problems, including bleeding ulcers
- stomach bleeding due to regular use of aspirin or other non-steroidal anti-inflammatory medicines (NSAIDs)
- bleeding haemorrhoids.
Increased needs for iron
Certain groups of people are more likely to have iron-deficiency anaemia. These include babies, teenagers and women who have heavy periods.
- Pregnancy. During pregnancy, a woman's daily iron requirements can leap from 18mg to 27mg. There are a number of reasons for this. During pregnancy, iron is needed to produce the extra maternal blood volume and to make all the blood for the growing baby. Your growing baby also lays down a store of iron in their liver to allow for growth and development until the age of six months or so, usually when they begin a mixed diet. This is important as milk is not a good source of iron. Unless your iron stores are very low to begin with, lack of menstruation in the pregnancy combined with your body's greater efficiency in absorbing iron from food and drink means that you probably won't need extra iron in the form of supplements. If you do wish to take any dietary supplements in pregnancy, including iron supplements, it's important to discuss this with your doctor first. This is because some vitamins and minerals can be toxic in large amounts, including iron.
- Premature infants. Babies who are born prematurely may have low levels of stored iron. This is because the majority of a baby's iron stores are built up in the later stages of pregnancy. If your baby is premature, your paediatrician will ensure that your baby receives the appropriate treatments.
- Children and toddlers. With every growth spurt, your child's body draws on iron stores to make more blood and muscle. That's why it's important to ensure that your child consumes iron-containing foods daily, such as eggs, lean meat and poultry, iron-fortified cereals, oily fish like tuna and whole grains. Additionally, eating plenty of fruit and vegetables can aid iron absorption.
- Athletes. Iron is lost in sweat so intense exercising increases the need for iron. Also, hard training means that your body lays down more muscle which adds to your iron requirements.
Other causes
- Reduced absorption of iron. Digestive disorders such as Crohn's disease and coeliac disease can damage the lining of the small intestine, preventing the normal absorption of nutrients including iron. Also, surgery on the stomach and/or small intestine can affect iron absorption and therefore how much iron your body is able to draw on.
- Low intake. You may develop iron-deficiency anaemia if you don't get enough iron in your diet.
- Other underlying conditions. If your GP suspects an underlying condition is causing low haemoglobin levels, you may be referred for further testing or to a specialist doctor.
Treating iron-deficiency anaemia
If the test results show that you are a little low on iron, you will be advised to increase iron-containing foods in your diet. If the results show that you are very deficient in iron, you may be prescribed a course of iron supplements together with advice on how to increase the iron in your diet.
A second blood test six months later will probably be suggested to check that your blood haemoglobin levels have built up enough - it can take this long to build up stores.
More about iron supplements
Your doctor may prescribe iron supplements, such as ferrous sulphate tablets. As iron supplements can have side effects, always read the accompanying consumer medicine information leaflet and ask your GP or pharmacist for advice if you have any questions.
Some of the side effects include nausea, heartburn, constipation and diarrhoea. They can also cause your faeces to turn black. These side effects may be reduced if you take the tablets after meals.
Iron supplements are available in pharmacies but it's important not to self diagnose iron deficiency anaemia. This is because symptoms such as tiredness can be due to a range of conditions. Also, it is possible to overdose on iron as the body does not excrete it well and this can be toxic to body tissues.
Eating to prevent iron-deficiency anaemia
On average, men need 8mg of iron a day and women need 18mg a day.
You can usually get all the iron you need from your diet. A healthy diet including lean meat contains enough iron for most adults. Red meat is a very rich source of iron that is easily absorbed by your body. Liver is a very rich source of iron, too, but it isn't recommended for pregnant women as it also contains very high levels of vitamin A which can harm the developing baby. For this reason, it is best to limit intake of liver to 50g at most per week.
Other good sources of iron include:
- iron-fortified cereals
- tuna and other oily fish
- pulses like red kidney beans, black beans, soybean and pinto beans
- tofu
- eggs
- wholegrain breads
- green vegetables such as spinach, kale and watercress
- dried fruit such as raisins, apricots and peaches.
Even if you don't eat lean meat, a well-planned vegetarian diet shouldn't trigger iron deficiency anaemia, especially if you eat eggs, pulses, leafy vegetables and fortified cereals. As vitamin C helps your body to absorb iron, including vitamin C-containing foods like tomato, capsicums, kiwi fruit or a glass of orange juice with your meal may help to raise your iron absorption. The iron in non-meat based foods isn't absorbed as easily as the iron in meat, so taking a source of vitamin C with your meals also helps to alter the chemical make-up of the iron and make it easier for your body to absorb.
Unprocessed bran can reduce the amount of iron your body absorbs. If you're using it to prevent constipation, try to boost your fibre instead by eating more whole grains, plenty of vegetables and fruits - and increase your water intake to help keep things moving.
What you drink affects how your body will absorb iron. Tea and coffee contain substances called polyphenols that can bind with iron and make it harder for your body to absorb it, so try not to drink it with meals. However, overall, research shows that tea and coffee consumption doesn't have a great deal of influence on iron status in most people in developed countries and societies.
Remember, if you eat a strict vegetarian or vegan diet, or another kind of restricted diet due to food allergies or intolerance, you may not be getting enough iron. In these cases speak with your GP or a registered dietitian as they can advise you on choosing the right foods for you.
Further information
Dietitians Association of Australia
www.daa.asn.au/
Food Standards Australia New Zealand
www.foodstandards.gov.au
The Royal Women's Hospital, Melbourne: Food safety during pregnancy
www.thewomens.org.au/Foodsafetyduringpregnancy
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