Iron Deficiency Anaemia: Symptoms, Causes, Tests & Treatment

Iron deficiency is common and can leave you feeling tired, weak, short of breath or unable to concentrate. If iron stores fall far enough, iron deficiency anaemia can develop because the body does not have enough iron to make adequate haemoglobin for healthy red blood cells.

However, fatigue does not automatically mean low iron. Appropriate blood tests can confirm iron deficiency. Importantly, a health professional should also investigate why the deficiency developed rather than simply recommending iron indefinitely.

What is iron deficiency anaemia?

Iron is an essential mineral and an important part of haemoglobin, the protein in red blood cells that carries oxygen around the body. Iron deficiency means your body’s iron stores are too low. Iron deficiency anaemia occurs when iron deficiency reduces your ability to make enough haemoglobin or healthy red blood cells.

You can have iron deficiency before anaemia develops. This is one reason symptoms and blood results need to be considered together.

What are the symptoms of iron deficiency anaemia?

Common symptoms can include fatigue, weakness, shortness of breath, dizziness or light-headedness, headaches, difficulty concentrating and pale skin. Some people have few or no symptoms, particularly when the deficiency develops gradually.

These symptoms are not specific to iron deficiency. Similar symptoms can occur with many other health conditions, so testing is more reliable than trying to diagnose low iron from symptoms alone.

What causes iron deficiency?

Iron deficiency develops when iron losses or requirements are greater than the amount the body absorbs. Causes include inadequate dietary iron, increased requirements during pregnancy, heavy menstrual bleeding, blood donation, gastrointestinal blood loss and conditions that reduce iron absorption.

Coeliac disease, inflammatory bowel disease and some forms of stomach or bariatric surgery can affect absorption. A doctor should investigate unexplained iron deficiency, particularly when there is no obvious dietary or menstrual explanation, to look for blood loss or another underlying cause.

Who is more likely to develop iron deficiency?

People with heavy periods, pregnant women, growing children and adolescents, frequent blood donors and people who have difficulty absorbing nutrients can have increased iron requirements or losses. Vegetarians and vegans also need to pay attention to dietary iron because the body absorbs plant-based iron differently from haem iron found in animal foods.

Being in a higher-risk group does not necessarily mean you are deficient. Blood testing can establish whether treatment is actually needed.

How is iron deficiency anaemia diagnosed?

A full blood count can identify anaemia by assessing haemoglobin and red blood cells. Iron studies provide additional information about iron status. Doctors commonly use ferritin to assess stored iron, while other measures can include serum iron, transferrin and transferrin saturation.

A health professional should interpret results in the context of your health because inflammation and illness can affect ferritin and other markers. Your doctor may order additional tests if the cause is not clear.

Why is ferritin important?

Ferritin is a protein that stores iron, and a ferritin blood test helps estimate the body’s iron stores. A low ferritin level can support a diagnosis of iron deficiency, but interpreting the result is not always as simple as comparing one number with a laboratory reference range.

Rather than aiming for an internet-based “ideal” ferritin number, discuss your result with a health professional who can interpret it alongside haemoglobin, other iron studies, symptoms and relevant medical conditions.

What foods contain iron?

Iron-rich foods include red meat and other meats, seafood and a range of plant foods such as legumes, tofu, nuts, seeds, wholegrains and iron-fortified cereals. Eating a varied diet can help maintain healthy iron intake.

Having vitamin C with a meal can improve absorption of non-haem iron from plant foods. Tea, coffee and some calcium-rich foods or supplements can reduce iron absorption when consumed at the same time, so timing can matter for people who are trying to improve iron intake.

Should you take an iron supplement?

Do not assume that fatigue means you need an iron supplement. Too much iron can be harmful, and supplementation can delay investigation of the reason your iron is low. Ideally, blood tests should confirm iron deficiency and a health professional should assess its cause before treatment begins.

Doctors commonly use oral iron to treat diagnosed iron deficiency anaemia, and treatment may need to continue for several months. The appropriate product, dose and schedule depend on your circumstances. Iron tablets can cause side effects such as nausea, constipation, abdominal discomfort and dark stools.

When might an iron infusion be considered?

A doctor may consider intravenous iron when you cannot tolerate oral iron, your body does not absorb it well, oral treatment has not worked adequately, or iron needs to be replaced more quickly in particular clinical situations. An appropriate healthcare professional should recommend and administer an infusion.

The best treatment depends on the severity of the deficiency, its cause, your medical history and how you respond to oral treatment.

Why is finding the cause of low iron important?

Replacing iron treats the deficiency, but it does not necessarily treat the reason it occurred. Heavy menstrual bleeding, gastrointestinal bleeding, inadequate intake and impaired absorption require different approaches.

Repeated or unexplained iron deficiency may require further investigation. This is particularly important if you have digestive symptoms, changes in bowel habits or visible or suspected blood loss. Further assessment is also important if iron levels continue to fall after treatment.

When should you seek medical advice?

See your doctor if you have persistent fatigue, weakness, shortness of breath, dizziness or other symptoms that make you concerned about anaemia or low iron. Medical assessment is also important if blood tests show iron deficiency without an obvious cause.

Seek urgent medical attention for severe shortness of breath, fainting, significant chest pain, vomiting blood, heavy uncontrolled bleeding, or black tar-like stools, particularly if you feel unwell.

Frequently Asked Questions

Can you have iron deficiency without anaemia?

Yes. Iron stores can become depleted before haemoglobin falls enough to meet the definition of anaemia. Blood tests help distinguish iron deficiency from iron deficiency anaemia.

Is tiredness always a sign of low iron?

No. Fatigue has many possible causes. If tiredness persists, seek appropriate assessment rather than starting iron based on symptoms alone.

What blood tests check iron levels?

Your doctor may request a full blood count and iron studies. These iron studies can include ferritin, serum iron, transferrin and transferrin saturation.

Can heavy periods cause iron deficiency?

Yes. Ongoing heavy menstrual blood loss is a common cause of iron deficiency and may need treatment as well as iron replacement.

Can gut problems cause low iron?

Yes. Conditions such as coeliac disease and inflammatory bowel disease can reduce iron absorption, while bleeding from the stomach or bowel can also cause iron loss.

Does vitamin C help iron absorption?

Vitamin C can improve absorption of non-haem iron, particularly iron from plant foods. A balanced meal containing vitamin C-rich foods can therefore help dietary iron absorption.

How long does iron treatment take?

Treatment often continues for several months, but the duration varies according to the severity and cause of the deficiency and your response. Your health professional may use follow-up blood tests to monitor progress.

Can too much iron be harmful?

Yes. Excess iron can be harmful, which is why you should not take iron supplements indefinitely without appropriate assessment and monitoring.

About Mick Jordan

Mick Jordan is a naturopath and Sports and Remedial Massage Therapist based in Brighton, Melbourne, with more than 30 years’ experience in natural therapies. He has a particular interest in nutrition, digestive health, sports performance and recovery, and takes an individual approach to helping clients improve their health and wellbeing.

Disclaimer: This article provides general health information and does not replace individual medical advice, diagnosis or treatment. Iron deficiency and anaemia can have important underlying causes. Speak with an appropriately qualified health professional before starting iron supplements and if you have persistent or concerning symptoms.