Iron and iron deficiency

What is iron?

Iron is an important mineral hat is involved in various bodily functions, including the transport of oxygen in the blood. This is essential for providing energy for daily life.

Good sources of iron include red meat, offal and iron-fortified breakfast cereals.

Iron is lost from the body through sweat, shedding intestinal cells, and blood loss.

About one third of the world’s population is iron deficient. Menstruating women are at greater risk than men and postmenopausal women of iron deficiency. It is thought that up to 5% of the Australian population has iron deficiency anaemia.

Roles of iron in the body

Some of the many roles of iron in the body include:

• Oxygen transport – red blood cells contain haemoglobin, a complex protein that carries oxygen from the lungs to the rest of the body. Haemoglobin is partly made from iron, and accounts for about two thirds of the body’s iron.
• Myoglobin – a special protein that helps store oxygen in muscle cells. Myoglobin contains iron and is responsible for the red colour of muscle.
• Enzymes – many enzymes throughout the body contain iron, including those involved in energy production. Enzymes are catalysts (increase the rate of chemical reaction) that drive many cell functions.
• Immune system– proper functioning of the immune system relies, in part, on sufficient iron. The immune system helps us fight infection.

Recommended dietary iron intakes

The average person needs to absorb just a small amount of iron each day to stay healthy (around 1 mg for adult males and 1.5 mg for menstruating females). To achieve this, however, we need to consume several times that amount. This is because our bodies absorb only a fraction of the iron contained in the foods we eat.

The Australian Recommended Dietary Intake (RDI) for iron is the amount of dietary iron required to meet the needs of most of the population. This amount is different for different age groups and life stages.

Recommended dietary intakes (per day)

Types of iron in our diets

The 2 types of iron found in our diets are:

• Haem iron – found in animal tissue such as beef, lamb, kangaroo, chicken and fish. Offal products such as liver and kidney are particularly rich in haem iron (however pregnant women should avoid eating too much offal as it contains large amounts of vitamin A, which can cause birth defects). This form of iron is most easily absorbed by the body.
• Non-haem iron – found in animal tissue, animal-based products and plant foods such as dried beans and lentils. Good vegetarian sources of non-haem iron include iron-fortified breakfast cereals, wholegrains and legumes (beans and lentils). If you are vegetarian and have no animal tissue in your diet, you may need almost twice as much dietary iron each day as non-vegetarians. Plant-based sources of iron include: dark green leafy vegetables such as broccoli, raisins, nuts, prunes, dried apricots, seeds, dried beans and peas, and iron-fortified cereals, breads and pastas.

How much iron do we absorb from our diet?

How much iron you absorb from your diet depends on how much iron your body is storing.

The healthy body absorbs around 18% of the available iron from a typical western diet (which includes animal foods) and about 10% from a vegetarian diet. However, you may be absorbing much less than that, even if your diet includes iron-rich foods.

The most significant influence on iron absorption is the amount of iron already stored in your body. The body stores iron in various places, including the liver. If your stores are high, your body absorbs less iron from the foods you eat. Conversely, low iron stores increase your ability to absorb iron.

Dietary factors affecting iron absorption

Certain foods and drinks affect how much iron your body absorbs.

To boost iron absorption:

• Consume vitamin C (found in fruits and vegetables).
• Include animal protein (haem) with plant (non-haem) sources of iron, such as meat with beans – for example, beef and kidney beans in a chilli con carne.
• Cook plant sources of iron (such as vegetables). In most cases, cooking increases the amount of available non-haem iron in vegetables. For example, the body absorbs 6% of the iron from raw broccoli, compared to 30% from cooked broccoli.

Foods and drinks that reduce your body’s ability to absorb iron:

• Soy proteins can reduce absorption from plant sources.
• Tea, coffee and wine contain tannins that reduce iron absorption by binding to the iron and carrying it out of the body.
• Phytates and fibres found in wholegrains such as bran can reduce the absorption of iron and other minerals.
• Inadequate vitamin A in your diet could lead to iron deficiency because vitamin A helps to release stored iron.
• Calcium and phosphorus reduce the absorption of plant-sourced (non-haem) iron.

High-risk groups for iron deficiency

One in 8 people aged 2 years and over does not consume enough iron on average to meet their needs. If you do not have enough iron in your body, it is called being ‘iron deficient’. This can make you feel tired and lower your immunity. Including iron-rich foods in your diet can help.

People who are at an increased risk of iron deficiency, include:

• babies given cow’s or other milk instead of breastmilk or infant formula
• toddlers, particularly if they drink too much cow’s milk
• teenage girls
• menstruating women, especially those who have heavy periods
• women using an IUD (because they generally have heavier periods)
• pregnant women
• breastfeeding women
• people with poor diets such as people who are alcohol dependent, people who follow ‘fad diets’, or people with eating disorders
• people who follow a vegetarian or vegan diet
• Aboriginal Australians
• athletes in training
• people with intestinal worms
• regular blood donors
• people with conditions that predispose them to bleeding, such as gum disease or stomach ulcers, polyps or cancers of the bowel
• people with chronic diseases such as cancer, autoimmune diseases, heart failure or renal (kidney) disease
• people taking aspirin as a regular medication
• people who have a lower than normal ability to absorb or use iron, such as someone with coeliac disease.

Stages and symptoms of iron deficiency

Most of your body’s iron is in the haemoglobin of your red blood cells, which carry oxygen to your body. Extra iron is stored in your liver and is used by your body when your dietary intake is too low.

If you don’t have enough iron in your diet, your body’s iron stores get lower over time.

This can cause:

• Iron depletion – when haemoglobin levels are normal, but your body only has a small amount of stored iron, which will soon run out. This stage usually has no obvious symptoms.
• Iron deficiency – when your stored and blood-borne iron levels are low and your haemoglobin levels have dropped below normal. You may experience some symptoms, including tiredness.
• Iron deficiency anaemia – when your haemoglobin levels are so low that your blood is unable to deliver enough oxygen to your cells. Symptoms include looking very pale, breathlessness, dizziness and fatigue. People with iron deficiency anaemia may also have reduced immune function, so they are more vulnerable to infection. In children, iron deficiency anaemia can affect growth and brain development.

Symptoms of iron deficiency anaemia in children

The signs and symptoms of iron deficiency anaemia in children may include:

• behavioural problems
• repeat infections
• loss of appetite
• lethargy
• breathlessness
• increased sweating
• strange ‘food’ cravings (pica) like eating dirt
• failure to grow at the expected rate.

Causes of iron deficiency in adults

In adults, some of the common causes of iron deficiency include:

• Not getting enough iron in your diet (also known as ‘inadequate dietary intake’). There are many reasons why someone’s dietary intake of iron could be too low, for example due to a poorly balanced vegetarian diet, chronic fad dieting or having limited access to a wide range of fresh foods.
• Blood loss – iron deficiency easily occurs in situations of chronic (ongoing) blood loss. Common causes include heavy menstrual periods, regular blood donation, regular nosebleeds, other chronic conditions that involve bleeding (such as peptic ulcers, polyps or cancers in the large intestine), and certain medications, particularly aspirin.
• Increased need for iron – if you are pregnant or breastfeeding your body needs more iron. If this increased need isn’t met, iron deficiency can quickly occur.
• Exercise – athletes are prone to iron deficiency because regular exercise increases the body’s need for iron in several ways. For example, hard training promotes red blood cell production (which requires iron), and iron is lost through sweating.
• Inability to absorb iron – healthy adults absorb about 10 to 15% of dietary iron, but some people’s bodies are unable to absorb or use iron from food.

Causes of iron deficiency in children

Major risk factors for the development of iron deficiency in children include:

• prematurity and low birth weight
• exclusive breastfeeding beyond 6 months (not introducing solids)
• high intake of cow’s milk in young children less than 2 years of age
• low or no meat intake
• vegetarian and vegan eating
• poor diet in the second year of life
• possible gastrointestinal diseases
• lead poisoning.

Babies, children and teenagers undergo rapid growth spurts, which increase their need for iron. The main causes of iron deficiency in children by age group include:

• Babies less than 6 months old – newborns receive their iron stores in the uterus (womb), which means the mother’s diet during pregnancy is very important. Low birth weight or premature babies are at increased risk of iron deficiency and will need iron supplements (under medical supervision only). See your doctor for further advice.
• Babies aged 6 months to one year – a baby’s iron stores run low in the second half of their first year. Iron deficiency can result if their diet doesn’t include enough iron-rich solid food. At around 6 months, 2 servings a day of plain, iron-fortified infant cereal mixed with breastmilk or infant formula can start to be given. Plain pureed meats can soon be offered with other solids, once your baby is used to the cereal. Late introduction of solids into the baby’s diet is a common cause of iron deficiency in this age group.
• Children aged one to 5 years – breastmilk contains a small amount of iron, but prolonged breastfeeding can lead to iron deficiency, especially if breastmilk replaces solid foods in the diet. Low-iron milks such as cow’s milk, goat’s milk and soymilk should not be given until 12 months of age. Children who drink milk in preference to eating solid foods are in danger of iron deficiency.
• Teenagers – adolescent girls are at risk because of a number of factors, including growth spurts at puberty, iron loss through periods (menstruation) and risk of under-nutrition due to fad dieting that restricts eating.
• In general – gastrointestinal disorders, such as coeliac disease, are a rare but possible cause of anaemia in children.

Suggestions for parents – babies

Some suggestions to prevent iron deficiency in babies less than 12 months of age include:

• Have an iron-rich diet during pregnancy. Red meat is the best source of iron.
• Tests to check for anaemia should be conducted during pregnancy. If your doctor prescribes iron supplements, take them only according to instructions.
• Breastfeed your baby or choose iron-fortified infant formulas.
• Don’t give your baby cow’s milk or other fluids that may displace iron-rich solid foods before 12 months of age.
• Don’t delay the introduction of solid foods. Start giving your baby pureed foods when they are around 6 months of age. Fortified baby cereal made with iron-fortified infant formula or breastmilk is generally the first food to offer. This is because of its iron content, but also because its texture is easy to change. Introduce soft lumpy foods or mashed foods at around 7 months.

Suggestions for parents – young children

To prevent iron deficiency in toddlers and preschoolers:

• Include lean red meat in their diet 3 to 4 times a week. Offer meat alternatives such as dried beans, lentils, chickpeas, canned beans, poultry, fish, eggs and small amounts of nuts and nut pastes. These are important sources of iron in your child’s daily diet. If your family follows a vegan or vegetarian diet, you may need to seek advice from a dietitian to ensure you are meeting all your child’s dietary needs.
• Include vitamin C in their diet as this helps the body to absorb more iron. Make sure your child has plenty of foods rich in vitamin C like oranges, lemons, mandarins, berries, kiwifruit, tomatoes, cabbage, capsicum and broccoli.
• Encourage solid foods at mealtimes and take care that toddlers are not ‘filling up’ on drinks between meals.
• Remember that chronic diarrhoea can deplete your child’s iron stores, while intestinal parasites such as worms can cause iron deficiency. See your doctor for prompt diagnosis and treatment.
• Fussy eaters may be at risk due to poor intake or lack of variety in the foods they eat. Seek advice from your dietitian, local doctor or child health nurse on how to manage a fussy eater.

Suggestions for parents – teenagers

To prevent iron deficiency in teenagers:

• Talk to your child about the importance of iron. Help them become informed enough to make their own responsible food choices.
• Encourage iron-rich foods and meals, such as iron-fortified breakfast cereals and breads, and serve meat, poultry or fish with the evening meal.
• Offer good sources of non-haem iron such as dried beans, lentils, peas, broccoli, spinach, beans, fortified cereals, breads and whole grains if your child wants to avoid red meat or become vegetarian. Vitamin C-rich foods should also be encouraged, such as fruits or vegetables with meals.
• Encourage only moderate amounts of tea and coffee, as these can interfere with iron absorption.

Diagnosis of iron deficiency

Make an appointment with your doctor if you think you may be iron deficient. Diagnosis aims to exclude other illnesses that can have similar symptoms, such as coeliac disease.

Diagnosis methods include:

• physical examination
• medical history
• blood tests.

Treatment for iron deficiency

Treatment for iron deficiency depends on your iron status, and the underlying cause:

• If you have iron depletion , your doctor will give you information about including iron-rich foods in your diet. You will have another blood test in around 6 months to check that your iron level has improved.
• If you have iron deficiency , your doctor will give you dietary advice and closely monitor your diet. They will encourage you to have iron-rich foods and discourage you from having foods and drinks (such as bran, tea and coffee) that can interfere with iron absorption with meals. They will regularly review your iron status and may prescribe supplements.
• If you have iron deficiency anaemia , your doctor will prescribe iron supplements. It may take 6 months to one year for your body to restock its iron stores. Your iron levels will be regularly reviewed with blood tests.
• If you have an underlying problem that is causing your iron deficiency, it is very important that the cause is investigated. If it is a medical cause, it is important that it be treated appropriately.

Don’t self-diagnose iron deficiency

Since iron supplements are available without prescription, it can be tempting to self-diagnose, but this is not recommended because:

• Having too much iron in the body can be toxic and even fatal.
• Fatigue, paleness, dizziness and breathlessness are symptoms of many other health conditions, not just iron deficiency anaemia. Some of these other conditions are serious. Incorrectly self-diagnosing and self-medicating can be dangerous and can waste valuable time in getting the treatment you need. Getting the right treatment in the early stages of a disease offers a greater chance of recovery. So always visit your GP if you think you could be iron deficient.
• Iron supplements won’t help the symptoms if iron deficiency anaemia isn’t the problem. And you could be spending money on tablets you or your child don’t need.
• Taking an iron supplement when you don’t need it can interfere with your body’s absorption of other minerals, including zinc and copper.
• About one in 300 people have haemochromatosis, which is an inherited condition that prompts the body to absorb more iron than usual. Excess iron damages the body’s tissues and increases the risk of cancers and heart disease. People with haemochromatosis need to limit how much iron they consume.

Do not self-diagnose or give your child over-the-counter iron supplements, because an overdose of iron can cause death. In infants and young children, 20 mg per day is the safe upper limit – most iron supplements contain around 100 mg per tablet.

It is important to keep iron supplements tightly capped and away from children’s reach, as iron tablets are often mistaken as lollies by children.

If you suspect an iron overdose, call your doctor or the Victorian Poisons Information Centre on 13 11 26 immediately (24 hours, 7 days) or visit your local hospital emergency department.

Iron supplements

If you’ve been advised to take iron supplements, keep in mind that:

• The most common side effect of iron supplements is dark coloured or black stools (poo), so don’t be alarmed by this change to your bowel habits.
• Other common side effects include nausea, vomiting, constipation and diarrhoea. See your doctor for advice but, generally speaking, treatment involves lowering the recommended dose for a short time to give the body time to adjust.
• Iron supplements should be taken on an empty stomach, if possible.
• Supplements should be taken exactly as advised by your doctor. The human body isn’t very good at excreting iron and you could poison yourself if you take more than the recommended dose.

Where to get help

• Your GP (doctor)
• Dietitians Australia Tel. 1800 812 942
• Victorian Poisons Information Centre Tel. 13 11 26 (7 days, 24 hours) – for advice about poisonings, suspected poisonings, bites and stings, mistakes with medicines and poisoning prevention advice.