Iron Deficiency (Anemia)
Written by Ada’s Medical Knowledge Team
What is iron deficiency?
Iron deficiency refers to inadequate levels of the mineral iron in the body. The term is commonly used interchangeably with anemia: a condition often caused by iron deficiency, where the body either cannot produce a sufficient number of healthy red blood cells, or enough of the protein (hemoglobin) that allows red blood cells to carry oxygen around the body.
However, health problems may arise before iron levels drop to the extent that anemia develops. For this reason, the terms “iron depletion” and “non-anemic iron deficiency” are sometimes also used. 1
Iron is a micronutrient that is vital for the healthy functioning of the body. It is an important part of the production of red blood cells, skin, hair, nails, muscles and hormones. Iron also plays a key role in the functioning of nerve cells. 2
For many people, a balanced and varied diet provides all the iron they need. Good sources of iron include liver, meat, beans, nuts, whole grains, fortified breakfast cereals and dark-green leafy vegetables. 3
However, iron deficiency is very common in both developing and developed countries, making it the most widespread nutritional disorder in the world. 4 Groups of people who are particularly at risk of developing iron deficiency include pregnant women, premenopausal women, infants, children, teenagers and the elderly. 1 5
Iron deficiency may be the result of a number of different factors and conditions. Some of the most common causes of iron deficiency are inadequate dietary intake, continuous blood loss, increased need and inadequate absorption. 1 5
Symptoms of iron deficiency do not always manifest until iron-deficiency anemia develops, but may include fatigue; paleness; dizziness; an inability to concentrate and diminished productivity; unhealthy nails, skin and hair and a painful tongue, among others. 1 5
If left untreated, iron-deficiency anemia can have serious consequences, including increased susceptibility to illness and infection, 6 pregnancy complications, impaired cognitive and physical development, heart failure 7 and increased risk of morbidity in children. 4 However, iron deficiency is generally fairly easy to treat by addressing underlying conditions, making dietary modifications and taking supplements where necessary. 1 ref4 5
Iron deficiency symptoms
Tiredness and a reduced ability to exercise may be experienced before anemia develops. 8 However, signs of low iron may not be noticeable in many people until the deficiency has advanced to anemia. ref1 Even then, some people may present with few or no symptoms. 6 ref10 The severity of the symptoms typically depends on how rapidly anemia develops and the extent of the deficiency. ref9 9
People experiencing possible symptoms of iron deficiency can use the free Ada app to carry out a symptom assessment.
- Difficulty concentrating on work or studies
- Memory problems
- Faintness and dizziness
- Reduced ability to exercise
- Pale complexion
- Poor condition of hair, sometimes with hair loss
- Brittle nails that break easily, change shape or develop ridges
- Slow-healing wounds
- Sore, inflamed tongue
- Sores at the corners of the mouth
- Restless legs syndrome
- Delayed development in babies
Less common symptoms
- Tinnitus (ringing in the ears)
- Changes in sense of taste
- Chest pain (usually in people where there is pre-existing heart disease)
- Craving or eating clay, chalk, coal, ice, paper or other non-food substances (Pica syndrome)
- Difficulty swallowing (very rare)
Many of the symptoms of iron deficiency are nonspecific and may be indicative of other conditions. 12 10 In addition, there are a number of different types of anemia, all of which require different treatments. For this reason, it is important to consult with a medical practitioner should any of the above symptoms present.
Causes of iron deficiency
There are a number of possible causes of iron deficiency (which may lead to iron-deficiency anemia). Many of these involve different types of blood loss, which equates to the loss of cells that contain iron. An iron deficiency can result as a consequence.
- Dietary deficiency. A diet that is lacking in iron can lead to iron deficiency and iron-deficiency anemia. This is more common in developing countries and people who follow very restrictive diets.
- Menstruation. Women with heavy menstrual periods may develop iron deficiency if the amount of iron in their diet is insufficient to replace that lost during their periods.
- Pregnancy. Women who are pregnant require more iron than usual, and anemia often results when the levels in their diet are insufficient to support both their needs and those of the baby.
- Bleeding from the gut. Certain conditions can cause bleeding from the stomach and intestines. These include stomach or duodenal ulcers, inflammation of the large intestine or oesophagus, hemorrhoids and bowel cancer, among others. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) like aspirin and ibuprofen can also sometimes cause bleeding.
- Bleeding from the kidneys. Certain conditions that affect the kidneys and bladder can cause bleeding and subsequent iron loss.
- Impaired absorption. Certain health conditions can impede absorption of iron from the gut. These conditions include celiac disease, infections with the bacteria Helicobacter pylori (H.pylori), 8 and inflammatory bowel disease, among others. Gastric surgery may also lead to impaired absorption of iron.
- Parasitic infection. Hookworm infection can result in chronic blood loss and is a major cause of iron deficiency worldwide. Those living in or traveling to certain tropical countries are particularly at risk.
- Malaria. A relationship exists between malaria and iron deficiency in tropical parts of the world.
Other possible causes of iron deficiency include blood loss from surgery, chronic inflammatory conditions like rheumatoid arthritis, 1 cancer and overtraining in athletes. 8 Diets very high in substances that interfere with iron absorption (for example, dairy, tea and phytates) may also be implicated in the development of iron deficiency. ref1 7 Heavy nosebleeds and blood donation can also lead to iron deficiency, though these potential causes may be overlooked by healthcare practitioners. 9
Anemia means that the body doesn’t have enough healthy red blood cells and hemoglobin to transport oxygen around the body. Iron-deficiency anemia is caused due to lack of iron and hemoglobin, which are needed for binding oxygen to the red blood cells.
This condition may develop when the body does not have enough iron to make red blood cells. This condition often occurs after someone loses large amounts of blood or during pregnancy when the body needs more iron than normal. It can also occur slowly over time if a person can’t or doesn’t take in enough iron. Iron deficiency is one of the most common causes of anemia. This condition is most common in women of childbearing age.
Diagnosis of iron deficiency
After taking the person’s medical history and performing a physical examination, a doctor will typically request blood tests to confirm the diagnosis of iron deficiency. 13
A blood test called a full blood count (FBC) is used to examine the number and size of the red blood cells and the amount of haemoglobin (the iron-containing molecule) in the red blood cells. The results of this test will generally indicate whether the person has anemia and what kind of anemia it may be. This can help the doctor to identify possible causes. However, because there are multiple different types and causes of anemia, further tests may be required. 7
Other blood tests may be ordered to check the levels of ferritin in the blood – this usually provides a good indication of the total iron stores in the body. Low ferritin levels typically indicate iron deficiency. However, the results may be unreliable if there is any infection or inflammation, as well as in cases where heart failure, liver disease, cancer or hyperthyroidism is present, as these conditions may be accompanied by unusual ferritin levels. 1 7
If the cause of the iron deficiency is not clear, the doctor may recommend one or more of the following diagnostic tests: 7
- Fecal (stool) tests and a rectal exam to check for health conditions that may be contributing to the deficiency
- An endoscopy to examine the state of the stomach and intestines
- A colonoscopy to examine the state of the bowel and rectum
- An abdominal computed tomography or CT scan
- Blood tests and sometimes a gut biopsy (where a small piece of the small intestine is removed and sent for tests) for celiac disease
- Blood tests to assess thyroid, liver and kidney function
- Bone marrow biopsy (where a small portion of bone marrow is removed and sent for tests)
The doctor may need to differentiate the diagnosis of iron deficiency from other conditions that can cause many of the same symptoms, such as thyroid disorders. 7 People experiencing symptoms that may be linked to iron deficiency or a related condition can use the free Ada app to carry out a symptom assessment.
Prevention of iron deficiency
While it is not always possible to prevent iron deficiency, people can take steps to reduce their risk of developing the condition. These include: 1
- Eating a diet that contains iron-rich foods
- Avoiding excessive consumption of substances that can interfere with iron absorption (such as tea, coffee and cow’s milk)
- Taking precautions to prevent malaria when traveling to regions where the disease is prevalent
- Regular screening where there is a high risk of iron deficiency
It is not advisable to take iron supplements unless an iron deficiency has been confirmed by a medical practitioner, as taking more iron than needed can cause side-effects and interfere with the absorption of other important minerals. Too much iron can be toxic. 5
Iron deficiency treatment
Treatment for iron deficiency and iron-deficiency anemia typically involves addressing the underlying cause, increasing the amount of iron in the diet and sometimes taking iron supplements. Both liquid and tablet iron supplements are available; a doctor will advise on the type and dosage required. The length of time a person needs to take an iron supplement will depend on the severity of the iron deficiency. 7
Commonly prescribed iron supplements include ferrous sulfate, ferrous fumarate and ferrous gluconate – all of which are equally effective. 11 All iron supplements can be toxic in high doses, and should be kept out of reach of children.
Iron supplements may cause unpleasant side-effects, including nausea, stomach pain, heartburn, diarrhea and constipation. 11 Taking lower doses or taking the supplement with meals can help to reduce the likelihood and severity of these side-effects. 2 A doctor may advise taking the iron supplement with orange juice or vitamin C to enhance absorption of the mineral. 13
Not all cases of iron deficiency will require treatment with a medical supplement. If the deficiency is mild, it may be sufficient to take a natural supplement like a highly concentrated juice made from plants that are rich in iron. Some people may find this kind of supplement more palatable and easier to take on a regular basis.
A person with iron deficiency will typically start to feel better within a few days of starting their treatment program. 8 They will usually be asked to have follow-up blood tests a few weeks later to confirm that the treatment is working. Even after their iron levels have returned to the normal range, the treatment will usually continue for another three months or more, and the person will be asked to have regular blood tests to ensure that they do not develop iron deficiency again. 7
Unless the iron deficiency is related to a serious underlying health condition, the treatment is usually effective. 6
Iron deficiency FAQs
Q: Can iron deficiency cause hair loss?
A: Yes, iron deficiency can cause hair loss. The condition can also result in the hair, skin and nails appearing in a poor condition. 1
Q: Are vegetarians at greater risk of iron deficiency?
A: While iron found in some plant sources can be difficult to absorb, eating a well-balanced vegetarian diet is generally sufficient to prevent deficiency. The incidence of iron-deficiency anemia in vegetarians has not been found to differ greatly from non-vegetarians. However, poor or restrictive vegetarian diets may increase the risk of developing iron-deficiency anemia. 14 It is recommended that those following a vegan diet – young women in particular – have their iron status checked regularly and take supplements where necessary. 15
Q: What is latent iron deficiency?
A: Also known as depleted iron stores, latent iron deficiency refers to a lack of iron that may not be severe enough to cause anemia, but could cause other health problems. 1