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Anemia

What is anemia?

Anemia is the general name for a condition where the body either cannot make enough healthy red blood cells and/or has too little hemoglobin, the substance that enables red blood cells to transport oxygen around the body.[1]

There are many different types of anemia. These include, but are not limited to:[2][3][4][5]

  • Iron deficiency anemia: the most common type of anemia
  • Megaloblastic anemia: often caused by a deficiency of vitamin B12 or folic acid
  • Aplastic anemia: caused by damage or dysfunction in bone marrow cells
  • Hemolytic anemia: caused by red blood cells being destroyed at an increased rate

Medically speaking, anemia is broadly classified as macrocytic, microcytic or normocytic, depending on the size and volume of the red blood cells (erythrocytes):[6][7]

  • Macrocytic anemia: In this category of anemia, the red blood cells are larger than normal. This includes anemia caused by vitamin B12 deficiency or folate deficiency.
  • Microcytic anemia: In this category of anemia, the red blood cells are smaller than normal. This includes anemia caused by iron deficiency, thalassemia or sickle cell disease.
  • Normocytic anemia: In this category of anemia, the red blood cells are normal in size, but fewer than normal in number. This includes anemia caused by chronic conditions, e.g. kidney disease.

Regardless of the type or cause, common symptoms of anemia include:[8]

  • Tiredness and lethargy
  • Breathlessness
  • Faintness
  • Headaches

There may also be other symptoms specific to the type of anemia being experienced.

The treatment recommended for anemia depends on the underlying cause. In cases of iron or vitamin deficiency, treatment will typically involve dietary changes and sometimes the use of supplements or medications. In less common types of anemia, as well as severe cases, more complex approaches, such as blood transfusions, may be needed.[9][10][11]

The outlook depends on the type, cause and severity of anemia, as well as the age and overall health of the person; but with appropriate and timely treatment, recovery or effective management can be expected in many cases.[12]

If left untreated, anemia can lead to complications, including reduced ability to function, lower quality of life, lung problems and even heart failure.[13][12] It is important to consult a medical practitioner without delay, should the condition be suspected.

Types of anemia

There are a number of different types of anemia. These include the following:

Iron deficiency anemia

Iron deficiency anemia is caused by a lack of iron in the body, leading to reduced levels of sufficiently functioning red blood cells. Iron deficiency can be caused by a variety of factors and conditions, including internal bleeding, pregnancy, heavy menstruation, inflammatory bowel disease (IBD) and a lack of iron in one’s diet.[9]

Megaloblastic anemia

Megaloblastic anemia is a type of macrocytic anemia that can be caused by a lack of vitamin B12 or lack of folic acid (folate). This is most often due to a dietary deficiency or malabsorption, e.g. as in pernicious anemia, where the body cannot absorb sufficient amounts of vitamin B12.[3]

Aplastic anemia

Aplastic anemia is a consequence of damage or dysfunction in the bone marrow cells, causing them to produce fewer red blood cells than needed. This may be the result of a number of conditions, including infectious diseases and autoimmune disorders, as well as certain substances and cancer treatments. Rarely, aplastic anemia may run in families. Examples of hereditary conditions that can lead to aplastic anemia include Fanconi anemia and Diamond-Blackfan anemia.[4]

Hemolytic anemia

Hemolytic anemia occurs as a result of red blood cells being destroyed more quickly than usual. This can be caused by a number of different conditions, some of which may run in families. There are many types of hemolytic anemia. Two examples include thalassemia and sickle cell anemia, both of which are hereditary.[5]

Thalassemia

Thalassemia is a genetic disorder that affects the production and function of hemoglobin, causing red blood cells to break down more easily than normal. The condition may be mild or severe.[14]

Sickle cell anemia

This is a common, severe, form of sickle cell disease – a group of conditions that cause hemoglobin to be abnormally shaped and red blood cells to break down more easily than normal. Sickle cell disease is acquired genetically.[15][16]

Anemia symptoms

Common symptoms of anemia, regardless of the cause, include:[8]

  • Fatigue (tiredness)
  • Lethargy (lack of energy)
  • Breathlessness
  • Faintness
  • Headaches

Less common symptoms of anemia may include:[1][17]

  • Paleness
  • Palpitations (the feeling that the heart is skipping a beat or pounding)
  • Tinnitus (ringing in the ears)
  • Muscle cramps
  • Loss of appetite
  • Altered sense of taste

There may also be other symptoms, depending on the type of anemia. For example, iron deficiency anemia may cause wounds to heal slowly and brittle nails. VItamin B12 deficiency anemia may cause pins and needles, confusion and depression.

In the early stages of anemia, some people may not experience symptoms.[18]

Anemia causes

There are many possible causes of anemia. These include:[9][19]

  • Dietary deficiencies of essential vitamins and minerals, such as vitamin B12, folic acid and iron
  • Malabsorption of nutrients, e.g. in celiac disease, Crohn’s disease
  • Substantial blood loss, e.g. from heavy menstruation or inflammatory bowel disease
  • Bone marrow problems and leukemia
  • Certain chronic conditions, e.g. rheumatoid arthritis, kidney disease (anemia of chronic disease)
  • Certain genetic disorders, e.g. thalassemia and sickle cell disease
  • Certain infections, e.g. malaria
  • Certain medications and therapies, e.g. some types of painkillers, antibiotics, drugs for hyperthyroidism[17] and cancer treatments[18]
  • Periods where the body needs more energy than usual, such as puberty and pregnancy

Diagnosis of anemia

As the first step, a doctor will typically take the person’s medical history and perform a physical examination. They may then order blood tests to check:[19][18]

The doctor may also ask for the following tests to be done:[19][18]

  • Urine tests
  • Stool (feces) tests
  • A bone marrow biopsy, removing a small sample for examination
  • A gastroscopy or colonoscopy to examine the digestive tract

As effective treatment of anemia depends on identifying the cause, the doctor will attempt to establish what this is. Further tests may be required if the cause is not clear.

Anemia treatment

The treatment recommended will depend on the underlying cause, as well as the severity of the anemia. Treatment may include:[19][18]

  • Dietary changes to include more iron or vitamin-rich foods
  • Vitamin or iron supplements
  • Antibiotics, in the case of certain infections
  • Hormonal medication, in some cases of heavy menstruation[20]
  • Adjusting any medications or therapies that may be causing anemia

In severe or persistent cases of anemia, the following may be recommended:[19][18][21]

  • Medication to stimulate the production of red blood cells or to slow down their destruction
  • Medication to suppress the immune system, where this is involved[17]
  • Blood transfusions
  • Bone marrow transplants
  • Surgery to stop internal bleeding
  • Surgery to remove the spleen, where it is rapidly destroying red blood cells

Complications of anemia

If severe or left untreated, anemia can cause a number of complications, including the following:[22]

  • Lasting fatigue leading to diminished productivity
  • Weakened immune system
  • Fast or irregular heartbeat
  • Heart failure
  • Problems during pregnancy, including fatigue, preterm labour and problems with fetal development[23]
  • Increased risk of postpartum depression

Specific types of anemia may cause other serious complications. If any kind of anemia is suspected, it is very important to consult a medical practitioner without delay.

Prevention of anemia

While it may not be possible to prevent all types of anemia, steps can be taken to reduce the risk of developing anemia related to nutritional deficiencies. These include:[19][21]

  • Eating a well-balanced diet
  • Eating fortified foods and/or taking vitamin and mineral supplements where one’s diet is restrictive, e.g. vegetarians and vegans
  • Avoiding regular consumption of tannin-containing tea or coffee with meatless meals, as this may interfere with absorption of iron from plant sources[24]

Anemia FAQs

Q: Is anemia during pregnancy common?
A: Yes. Mild anemia is quite common during pregnancy, as a pregnant person needs more iron than usual.[19] It is recommended that a pregnant person eat foods that are rich in iron, such as dark green leafy vegetables, fortified cereals, eggs, nuts and lean meats to help prevent iron deficiency anemia. A doctor may also recommend a vitamin and mineral supplement. They may order blood tests to check the person’s iron levels during pregnancy. If any symptoms of anemia are present, a pregnant person should consult a doctor without delay.[25]

For more information about achieving a balanced diet during pregnancy, see these resources on foods to eat during pregnancy and foods to avoid during pregnancy.

Q: What are the best foods for anemia?
A: It depends on the type of anemia and what is causing it. In the case of iron deficiency anemia, iron-rich foods such as dark green leafy vegetables, fortified cereals, eggs, nuts and lean meats may be recommended to help treat the condition.[19] In the case of anemia caused by a deficiency of vitamin B12 or folic acid, other types of food may be recommended. In many cases, a well-balanced diet should provide sufficient nutrients to prevent anemia. If anemia is suspected, it is important to consult a medical practitioner, as self-diagnosis may be inaccurate.

Other names for anemia

  • Anaemia (UK spelling)
  • Lack of blood
  • Tired blood
  • Iron deficiency

  1. Patient. “Vitamin B12 Deficiency and Pernicious Anaemia.” July 3, 2016. Accessed March 27, 2018.

  2. NHS Choices. “Iron deficiency anemia.” January 14, 2016. Accessed March 27, 2018.

  3. MSD Manual. “Vitamin Deficiency Anemia.” Accessed March 27, 2018.

  4. National Heart, Lung, and Blood Institute. “What is Aplastic Anemia?” August 22, 2012. Accessed March 27, 2018.

  5. National Heart, Lung, and Blood Institute. “What is Hemolytic Anemia?” March 21, 2014. Accessed March 27, 2018.

  6. Healthline. “Megaloblastic Anemia.” September 30, 2016. Accessed May 8, 2018.

  7. eMedicinehealth. “Anemia.” November 17, 2017. Accessed May 8, 2018.

  8. NHS Direct Wales. “Anaemia, vitamin B12 and folate deficiency.” June 20, 2016. Accessed March 27, 2018.

  9. Patient. “Anaemia.” November 1, 2017. Accessed March 27, 2018.

  10. Monthly Prescribing Reference. “Anemia: Patient Information Fact Sheet.” June, 2013. Accessed March 27, 2018.

  11. National Heart, Lung and Blood Institute. “Anemia.” Accessed March 27, 2018.

  12. Pacific Heart, Lung and Blood Institute. “Anemia.” Accessed March 27, 2018.

  13. Patient. “Pernicious Anaemia and B12 Deficiency.” June 24, 2016. Accessed March 27, 2018.

  14. Patient. “Thalassaemia.” January 22, 2018. Accessed March 29, 2018.

  15. National Heart, Lung, and Blood Institute. “What is Sickle Cell Disease?” Accessed March 29, 2018.

  16. Patient. “Sickle Cell Disease.” November 1, 2017. Accessed March 29, 2018.

  17. Amboss. “Anemia.” February 2, 2018. Accessed April 2, 2018.

  18. American Cancer Society. “Anemia in People With Cancer.” February 13, 2017. Accessed March 30, 2018.

  19. Better Health Channel. “Anaemia.” March, 2014. Accessed March 30, 2018.

  20. Hematology-Oncology Associates of CNY. “How Is Anemia Treated?” Accessed March 30, 2018.

  21. KidsHealth. “Anemia.” October, 2016. Accessed March 30, 2018.

  22. Health Service Executive. “Anaemia, iron deficiency.” Accessed April 2, 2018.

  23. MSD Manual: Consumer Version. “Anemia During Pregnancy.” Accessed April 9, 2018.

  24. Healthline. “Do Coffee and Caffeine Inhibit Iron Absorption?” October 21, 2017. Accessed May 4, 2018.

  25. American Society of Hematology. “Anemia and Pregnancy.” Accessed April 2, 2018.