Iron deficiency symptoms: signs, causes and who is at risk

What is iron deficiency?

Iron deficiency means your body doesn’t have enough iron to meet its needs. It develops in stages. First your iron stores run down, often without any symptoms. If that carries on, your body can’t make enough haemoglobin – the oxygen-carrying protein in red blood cells – and you develop iron deficiency anaemia, which is when symptoms usually appear.

The NHS says heavy periods and pregnancy are very common causes of iron deficiency anaemia. The UK’s National Diet and Nutrition Survey also finds that many teenage girls and women have iron intakes below the lowest reference level – though a low intake on paper is not the same as a diagnosis.

What are 5 signs of low iron?

The NHS lists these as the most common symptoms of iron deficiency anaemia:

• tiredness and lack of energy
• shortness of breath
• noticeable heartbeats (heart palpitations)
• paler skin than usual
• headaches

Less common symptoms include ringing, buzzing or hissing noises in your head (tinnitus), food tasting strange, feeling itchy, a sore tongue, hair loss, wanting to eat non-food things such as ice or paper (pica), difficulty swallowing, painful sores at the corners of the mouth, spoon-shaped nails and restless legs.

Can iron deficiency anaemia cause nausea?

Nausea isn’t one of the typical symptoms the NHS lists for iron deficiency anaemia. It is, however, a common side effect of iron tablets, so if you’re already taking iron and feel sick, that may be the reason – see Iron tablets side effects. If you feel sick often and don’t know why, talk to your GP.

What drains iron from your body?

Most iron deficiency in adults comes from losing blood, absorbing too little, or needing more:

• Heavy periods – a very common cause in women.
• Bleeding in the stomach or bowel, which you may not notice. It can be caused by long-term use of anti-inflammatory painkillers such as ibuprofen and aspirin, stomach ulcers, inflammation of the bowel or food pipe, piles and, less often, bowel or stomach cancer.
• Pregnancy, when the body needs more iron.
• Giving blood regularly, as each donation removes iron with the red blood cells.
• Gut conditions that reduce absorption, such as coeliac disease.
• A diet low in iron, or drinking a lot of tea or coffee with meals, which makes it harder to absorb iron from food.

In men and in women after the menopause, iron deficiency is less likely to be down to diet alone, which is why doctors look carefully for blood loss.

Who is most at risk of iron deficiency?

• Women and girls who have periods, especially heavy ones.
• Pregnant women.
• Regular blood donors.
• Vegetarians and vegans, because iron from plant foods is absorbed less readily than iron from meat and fish. A well-planned plant-based diet can provide enough – see Iron-rich foods.
• People with coeliac disease or other conditions that affect the gut.
• Teenage girls, whose iron needs rise to the adult women’s level from the age of 11.

How is iron deficiency diagnosed?

With a blood test, arranged by your GP. A full blood count shows whether your haemoglobin and red blood cells are lower than they should be. Your GP may also check ferritin, a protein that reflects how much iron you have stored – it can be low before anaemia develops.

Just as important is finding the cause. Your GP will ask about your periods, diet and any medicines, and may arrange further tests – for example a stool test (FIT) to look for hidden blood, a blood test for coeliac disease, or a referral to a specialist. Treating the low iron without finding why it’s low can miss something that needs attention.

Should you take iron if you think you’re low?

Not before you’ve had a blood test. Self-treating can mask the problem, delay the right diagnosis and, if you don’t actually need iron, cause harm – iron builds up in the body because there’s no active way to get rid of it.

If you’re diagnosed with iron deficiency anaemia, your GP will usually prescribe iron tablets and tell you how to take them, and will treat the underlying cause. They’ll normally repeat your blood test to check it’s working. You may also be advised to eat more iron-rich foods.

When should you see a GP?

See your GP if you have symptoms of iron deficiency anaemia, if you’ve been feeling tired for weeks for no obvious reason, or if you have heavy periods that affect your daily life. Get urgent medical help – call 111, or 999 in an emergency – if you notice blood in your poo, black, sticky, tar-like poo or you’re vomiting blood, or if you have chest pain or severe shortness of breath.