Iron deficiency anaemia: symptoms, causes and treatment

Iron deficiency anaemia happens when low iron stores limit the body's ability to make healthy red blood cells that carry oxygen.

Iron is needed to make haemoglobin, the part of red blood cells that transports oxygen around the body. Low iron may develop through blood loss, reduced iron intake, increased iron needs or difficulty absorbing iron from food. Finding the reason is as important as restoring iron.

Fatigue, generalised weakness and pale skin are common presentations of iron deficiency anaemia. Some people also notice dizziness, shortness of breath on exertion, palpitations, restless legs or difficulty concentrating. Symptoms can build gradually and overlap with many other conditions, so they should be assessed in context.

Blood loss is a frequent cause, including heavy periods or bleeding from the digestive tract. Pregnancy and other stages of increased demand can deplete iron stores. A diet low in iron-rich foods, conditions that reduce absorption, or repeated blood donation may also contribute. Do not assume that heavy periods are the only explanation; a clinician may need to look for another source.

The body can use stored iron for a time before anaemia develops. As stores fall further, oxygen delivery may be reduced and tiredness or reduced exercise tolerance may become more noticeable. Replacing iron without addressing ongoing loss can allow the problem to return.

People with heavy menstrual bleeding, restrictive eating patterns, a history of digestive disease, recent blood loss or increased iron needs may be more likely to develop low iron. Children, adolescents and people who are pregnant may have changing needs that merit individual clinical advice. Medicines that affect the stomach or bowel can also be relevant to absorption or bleeding risk.

A blood test can check haemoglobin and iron-related markers. The results are considered alongside symptoms, diet, bleeding history, pregnancy status, medicines and any bowel symptoms. Further tests may be recommended when the cause is unclear or when blood loss needs investigation. Follow-up testing helps show whether treatment is rebuilding iron stores.

Treatment usually combines iron replacement with management of the cause. A clinician may recommend an iron supplement and explain how to take it, what side effects to watch for and when to repeat tests. Food choices can support iron intake, and nutrition counselling may help make a realistic plan. When heavy periods are driving iron loss, treatment aimed at bleeding control, including a hormonal coil for some people, may be discussed.

Take supplements exactly as advised and mention nausea, constipation, diarrhoea or difficulty keeping them down. Keep appointments for repeat blood work even if energy improves, because symptoms can improve before iron stores have recovered. Seek urgent care for chest pain, fainting, severe breathlessness, black stools or vomiting blood.

A varied diet that includes iron-containing foods can support healthy stores, but diet alone may not correct ongoing blood loss or poor absorption. Attend reviews for heavy periods or digestive symptoms, and avoid starting high-dose iron without knowing why your level is low. A plan that treats the source of loss offers the best chance of preventing return.