Iron is essential for almost every aspect of your health. This is because it is a critical part of your blood, which contains haemoglobin.
Haemoglobin is made of globin proteins and iron-containing molecules called heme. Heme molecules bind to oxygen, via their iron molecules, and in doing so allow oxygen to be transported throughout your body. When your iron levels drop, you can’t form enough haemoglobin and iron-deficiency anaemia develops.
As iron can’t be made by your body, you need to get enough iron from your diet to support a healthy blood supply.
Iron in your diet is absorbed via your small intestines, which is why any illnesses that affect your small intestine (eg coeliac disease, Crohn’s disease) can cause iron-deficiency anaemia.
Once iron is absorbed into your blood supply, it is stored in your bone marrow, liver, muscles and spleen as ferritin and is released whenever it is needed. Any excess iron is removed via your stools.
If you stop eating foods that contain iron, your iron stores are quickly depleted, leading to iron-deficiency anaemia.
There are three main groups of people who are at risk of iron deficiency anaemia:
However, iron deficiency anaemia can develop at any age and should always be investigated to rule out any underlying health conditions that may be responsible (eg bowel cancer, Crohn’s disease, coeliac disease).
Iron in your diet comes in two forms: heme iron and non-heme iron. Heme iron only occurs in animal flesh (eg meat, poultry) and seafood. Non-heme iron is found in certain plants (eg leafy greens, legumes, nuts, seeds, whole grains), fortified foods (eg fortified cereals) and in the flesh of animals that eat plants.
It is harder for your gut to absorb non-heme iron than heme iron. The absorption of non-heme iron can be improved by taking vitamin C with your meal. Conversely, absorption can be impaired by consuming large amounts of calcium (eg via supplements), bran fibre and plant substances called phytates (eg as found in chapatis, certain grains, nuts and seeds) and tannins (eg as found in coffee, tea, wine and berries).
There is a common misconception that iron deficiency anaemia is more common in vegetarians and vegans. However, this is not necessarily true. As long as you get enough foods in your diet that contain iron and can be absorbed, you can avoid iron deficiency anaemia, whether or not you are vegetarian or vegan.
Aside from meat, poultry and seafood, other iron-rich foods include lentils, leafy green, whole grains, legumes, nuts and fortified cereals.
As eating high amounts of red and processed meats increases your risk of bowel cancer, it is important to take a balanced approach. As red meat is high in iron, an adult-sized portion once a week is usually enough to meet your body’s iron requirements.
In most cases, iron deficiency anaemia can be treated through dietary changes alone. However, if you have severe iron deficiency anaemia, your doctor may prescribe iron supplements as tablets, capsules, syrups or in extreme cases, as an intravenous infusion.
Iron supplements are usually prescribed with iron in a ferrous form ie as ferrous sulphate, ferrous fumarate or ferrous gluconate. The ferrous form of iron is easier for your body to absorb than the ferric form of iron.
Not everyone can tolerate iron supplements well as they can irritate the digestive system, causing excess acid and heartburn, as well as constipation and occasionally diarrhoea.
If you’re struggling to tolerate iron supplements, your doctor may reduce the dose, try a different form of iron or recommend you take your supplement on alternate days. If these approaches don’t work, your doctor will discuss alternatives.
Whether or not you can tolerate iron supplements well, you will notice that your stools become much darker or black. This is a normal consequence of taking iron supplements.
Dr Subramaniam Ramakrishnan is a Consultant Gastroenterologist at Spire Cheshire Hospital and Spire Tarporley Clinic, specialising in acid reflux and abdominal pain, gastrointestinal cancer, bowel problems, irritable bowel syndrome, coeliac disease, ulcerative colitis and Crohn's disease. He has performed over 8,000 diagnostic and therapeutic procedures, including gastroscopy, flexible sigmoidoscopy, colonoscopy and ERCP and introduced the capsule endoscopy service at Spire Cheshire Hospital. Dr Ramakrishnan is also actively involved in clinical research.
If you're concerned about symptoms you're experiencing or require further information on the subject, talk to a GP or see an expert consultant at your local Spire hospital.
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