Overview
Red blood cells carry oxygen around the body using , and haemoglobin is built around iron. When the body runs short of iron it cannot make enough healthy red cells, and the organs get less oxygen than they need. This is iron deficiency anaemia, the commonest form of anaemia in the world.
It builds up slowly. The body first uses up its stored iron, then the haemoglobin falls, and symptoms appear gradually enough that many people put them down to age, heat or overwork. Young children, adolescent girls, women with periods and pregnant women are affected most often.
Symptoms
Mild anaemia may cause nothing at all. As it deepens, the common complaints are:
- Tiredness and lack of energy
- Breathlessness, especially on climbing stairs or walking uphill
- A fast, thumping or irregular heartbeat
- Pale skin, and pale lips, tongue or inner eyelids
- Headache, dizziness or ringing in the ears
- Cold hands and feet
- Brittle or spoon-shaped nails, hair fall, a sore tongue, or cracks at the corners of the mouth
- A craving to eat ice, mud, chalk or raw rice
- Restless, uncomfortable legs at night
In children, iron deficiency can show as poor appetite, irritability, slow weight gain and difficulty concentrating at school.
When to see a doctor
See a doctor within the next few days for tiredness or breathlessness that is getting worse, for noticeable paleness, for heavy or prolonged periods, for a low result, or for anaemia found in a man or in a woman past menopause.
Causes
Iron runs low either because the body is losing blood, because it is not absorbing enough iron, or because it needs more than it is getting.
- Heavy or prolonged menstrual periods
- Pregnancy and breastfeeding, when the body's demand rises sharply
- Slow bleeding from the stomach or bowel, from ulcers, piles, inflammation or a growth
- Regular use of painkillers that irritate the stomach lining
- Hookworm and other intestinal worms
- A diet with little iron, which is easier to fall into on a diet with no meat, fish or eggs unless pulses and green vegetables are eaten well
- Conditions that stop iron being absorbed, such as coeliac disease or surgery on the stomach
- Rapid growth in infants, young children and teenagers
Risk factors
- Being a girl or woman who menstruates
- Being pregnant, or having had several pregnancies close together
- Being an infant, a young child or a teenager
- A diet low in iron, or heavy tea or coffee drinking with meals
- Living where hookworm or malaria is common
- Frequent blood donation
- Long term kidney disease or conditions that cause inflammation
Complications
Anaemia that is left alone makes the heart work harder to move oxygen around, which can cause a fast heartbeat and, over time, strain on the heart. Infections are harder to fight off, and daily life becomes limited by tiredness.
In pregnancy, anaemia raises the risk of premature birth, a low birth weight baby and serious problems for the mother around delivery. In infants and young children it can slow growth and affect learning and behaviour, and some of that effect may not be fully made up later.
Prevention
- Eating iron-rich foods regularly: green leafy vegetables, pulses, beans, jaggery, dried fruit, eggs, fish and meat
- Taking a source of vitamin C with meals, such as lemon, amla, guava or orange
- Keeping tea, coffee and milk to between meals rather than with them
- Using iron-fortified staples where they are available
- Taking iron and folic acid supplements in pregnancy as advised
- Deworming where the doctor or the local health programme advises it
- Getting heavy periods assessed rather than accepting them
Diagnosis
A full blood count shows the and the size of the red cells, which in iron deficiency are small and pale. Ferritin, which reflects the body's iron stores, is usually measured as well, although it can read falsely high when there is infection or inflammation.
The second half of the diagnosis is the cause. Depending on age, sex and symptoms, this may mean a stool test for blood or for worms, tests for coeliac disease, a look inside the stomach or the bowel with a camera, or a gynaecological assessment for heavy periods.
Treatment
Iron is usually given as tablets or syrup and continued for some months after the has returned to normal, so that the stores are refilled. Constipation, dark stools, nausea or tummy discomfort are common; taking the dose with food or less often usually helps, and the dark colour of the stool is harmless.
Iron given into a vein is used when tablets are not tolerated, not absorbed, or not working fast enough. A blood transfusion is reserved for severe anaemia or active bleeding. Alongside this, the cause is treated: heavy periods, an ulcer, piles, worms or coeliac disease, without which the anaemia simply comes back.
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“Anaemia is only weakness. Rest and good food will sort it out.”What is true?
Fact
Anaemia is a sign, not a diagnosis, and the important question is why the iron ran low. Heavy periods, worms and slow bleeding from the stomach or bowel are common reasons. Untreated anaemia also strains the heart and, in pregnancy, raises the risk for both mother and baby.
Myth“Beetroot, apples and pomegranate build blood because they are red.”What is true?
Fact
Colour has nothing to do with iron. Useful sources are green leafy vegetables, pulses, dried fruit, jaggery, eggs, meat, fish and fortified cereals. Once haemoglobin is already low, food alone will rarely correct it, which is why iron medicines are prescribed.
Myth“Once I feel better I can stop the iron tablets.”What is true?
Fact
Haemoglobin rises before the body's iron stores are refilled. Treatment is usually continued for several months after the count is normal so that the store is rebuilt, otherwise the anaemia returns.
Myth“Anaemia is a women's problem.”What is true?
Fact
It is commoner in girls and women because of periods and pregnancy, but men and older women get it too. In a man, or in a woman whose periods have stopped, iron deficiency often means slow bleeding from the stomach or bowel and needs to be investigated properly.
Myth“A cup of tea with the meal makes no difference.”What is true?
Fact
Tea, coffee and milk taken with food reduce how much iron the body takes in from that meal, while foods rich in vitamin C, such as lemon, amla or guava, increase it. Keeping tea and coffee to between meals is a small change that helps.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
My haemoglobin is normal now. Why must I keep taking iron?
Because the haemoglobin comes back up before the body's iron store does. If the tablets stop as soon as the count looks good, the store stays empty and the anaemia usually returns within months. Doctors generally continue iron for several months longer and then recheck.
The iron tablets upset my stomach. What can I do?
Tell the doctor rather than stopping on your own. Taking the dose with food, taking it every other day, or changing to a different iron preparation often settles the problem. Black stools while on iron are expected and are not a sign of bleeding, but stools that are black and tarry with a strong smell are different and need urgent attention.
Can I fix low haemoglobin with diet alone?
Diet keeps a normal level up and helps prevent anaemia, but once haemoglobin has fallen, food alone rarely brings it back in a reasonable time. Iron medicines do that, and diet then helps keep it there.
I am pregnant and my haemoglobin is low. Is that dangerous?
Anaemia in pregnancy is common and treatable, and it is taken seriously because it raises the risk of premature birth, a small baby, and problems for the mother around delivery. Iron and folic acid are given, the level is rechecked, and other causes are looked for if it does not improve.
