Anemia is when you have low levels of red blood cells. When this happens, your organs and tissues have a harder time getting oxygen. You may feel fatigue, weakness, and shortness of breath.

Anemia happens when the number of healthy red blood cells in your body is too low. Red blood cells are blood cells that carry oxygen to the organs and tissues of your body.

Every part of your body needs enough oxygen to function effectively.

Red blood cells contain an iron-rich protein called hemoglobin. Hemoglobin binds to oxygen in the lungs, allowing red blood cells to carry and deliver it throughout the body. Anemia is measured according to the amount of hemoglobin in the blood.

There are many different types and causes of anemia. Some types of anemia are mild and can be easily treated, while others can cause potentially serious health complications.

This article will explore the different causes and symptoms associated with anemia and explain how it is diagnosed and treated.

While there are many types of anemia, they cause similar symptoms. Many symptoms of anemia are associated with a lack of oxygen supply to the body’s organs and tissues.

If you have a type of anemia, you may experience general symptoms like:

If you have symptoms of anemia, it’s important to get medical attention, especially if you experience fainting or chest pain.

Other symptoms may happen with certain types of anemia. These depend on the type:

Iron deficiency anemia

Iron deficiency anemia is the most common type of anemia, and it occurs when you don’t get enough iron. An estimated 50% of all anemias result from iron deficiency.

You may have lower iron levels in your body due to:

  • blood loss, including heavy menstrual periods
  • not getting enough iron in your diet
  • health conditions that affect iron absorption

Many people with mild or moderate iron-deficiency anemia have no symptoms. However, anemia is often detected during routine blood tests.

Severe iron deficiency anemia symptoms can include:

Untreated, this type of anemia can cause potentially serious complications.

Vitamin-deficiency anemia

Vitamin deficiency anemia is caused by having lower-than-normal folate or vitamin B12 levels. You may get this type of anemia from a low dietary intake of these nutrients.

In addition to some of the general symptoms of anemia, anemia caused by low folate levels may also cause:

  • soreness of your mouth and tongue
  • color changes in your skin, hair, or nails

Pernicious anemia is a specific type of anemia caused by low levels of vitamin B12. Individuals with pernicious anemia often lack a protein made in the stomach called intrinsic factor that helps your body absorb vitamin B12 or have issues with the small intestine absorbing vitamin B12.

In addition to general anemia symptoms, symptoms more specific to deficiency in vitamin B12 include:

Hemolytic anemia

In hemolytic anemia, red blood cells are destroyed faster than your body can replace them. Causes of hemolytic anemia include:

In addition to general anemia symptoms, some additional symptoms more specific to hemolytic anemia include:

Aplastic anemia

Aplastic anemia happens when your bone marrow does not produce enough red blood cells. It results from damage to stem cells in the bone marrow that would normally develop into red blood cells. Because of this damage, fewer red blood cells are made.

Aplastic anemia usually results in the immune system damaging bone marrow stem cells. Other potential causes include:

  • medications
  • exposure to toxins
  • inherited genetic changes

Aplastic anemia can also affect white blood cell and platelet production. In addition to a low red blood cell count, this type of anemia can cause low counts of white blood cells and platelets.

In addition to general anemia symptoms, aplastic anemia can cause:

Anemia of inflammation or chronic disease

Anemia of inflammation or chronic disease happens when underlying health conditions cause inflammation in the body. This may cause anemia. For example, people with this type of anemia may:

  • have low levels of iron in the blood despite having a high amount of stored iron
  • produce less erythropoietin, a hormone that’s made in the kidneys and stimulates red blood cell production
  • have bone marrow that doesn’t respond well to erythropoietin
  • have red blood cells that have a life span that’s shorter than normal, meaning they die faster than they’re replaced

Many health conditions can cause anemia of inflammation or chronic disease. Some examples include:

Red blood cells are produced in your bone marrow and have an average life span of about 120 days. On average, your bone marrow produces 2 million red blood cells each second while approximately the same number are removed from circulation.

About 1% of your red blood cells are removed from circulation and replaced daily.

Any process that negatively affects this can cause anemia.

Experts categorize causes of anemia into those that:

  • decrease red blood cell production
  • increase red blood cell destruction or loss

Factors that decrease red blood cell production

When red blood cell production is reduced, more red blood cells leave the body than enter circulation, potentially leading to anemia.

Factors that decrease red blood cell production can be divided into two categories: acquired and inherited.

Acquired factors that can decrease RBC production include:

Some types of genetic (inherited) conditions may also decrease the production of healthy red blood cells. These include:

  • Fanconi anemia
  • Schwachman-Diamond syndrome
  • Diamond-Blackfan anemia
  • dyskeratosis congenita
  • amegakaryocytic thrombocytopenia

Factors that increase red blood cell destruction or loss

Anything that causes destruction or loss of red blood cells at a rate faster than they’re made can also cause anemia.

Acquired causes of increased red blood cell destruction can include:

Inherited causes of increased red blood cell destruction can include:

Certain factors may increase the risk of developing anemia. These include:

A diet rich in key nutrients may help prevent or manage some types of anemia.

Daily requirements for vitamins and iron vary according to sex, age, and pregnancy status. Some people may need to take supplements to get the recommended amount.

These nutrients include:

You may need more iron while you are menstruating or if you become pregnant.

Need a supplement?

If you know you have anemia, or aren’t getting enough of the above nutrients, you can find supplements in stores or online:

Before taking any supplements, talk to your healthcare professional to make sure the supplements you want to take are safe for you.

To diagnose anemia, a doctor may ask about your health history and family health history. Be sure to let your doctor know if you have a family history of anemia or a history of exposure to toxins in the home or workplace. They may also perform a physical exam.

Laboratory tests usually diagnose anemia. Some tests a doctor may order include:

Untreated, anemia can cause potentially serious complications. These may include:

It’s important to get treatment for anemia to avoid complications.

Treating anemia depends on what’s causing it. It usually involves treating the underlying cause of anemia. This can improve anemia.

Anemia caused by inadequate dietary iron, vitamin B12, or folate intake may be treated with nutritional supplements. Sometimes, you may need vitamin B12 injections if it isn’t absorbed properly from the digestive tract.

Your doctor or a nutritionist may work with you to prescribe a diet containing the appropriate amounts of vitamins, minerals, and other nutrients you may lack.

If anemia is severe, doctors may use drugs called erythropoiesis-stimulating agents to increase red blood cell production in the bone marrow. These drugs work similarly to the hormone erythropoietin, which your kidneys naturally produce.

If severe bleeding occurs or hemoglobin levels are very low, doctors may recommend a blood transfusion. During it, you’ll receive blood donated by an individual with a matching blood type.

The outlook for anemia depends on the cause and the response to treatment. Anemia is often treatable.

The outlook for anemia due to deficiencies in iron or vitamins is typically good if you receive a timely replacement of these important nutrients.

If you develop anemia due to a lack of key nutrients, you can pay attention to your diet to ensure you get the recommended daily amounts of iron, folate, and vitamin B12.

The outlook for anemia due to other causes can vary. Some people need long-term treatment to manage anemia or the underlying health conditions that cause it.

A doctor can tell you what to expect in your situation, including if you’re considering supplementation and whether it’s right for you.

Anemia is when you have low levels of red blood cells. When this happens, your organs and tissues have a harder time getting oxygen. As a result, you may experience symptoms like fatigue, weakness, and shortness of breath.

Your body replaces millions of red blood cells in circulation each day. When this process is disrupted, anemia can occur.

One of the more common causes of anemia is not getting enough nutrients, such as iron, folate, or vitamin B12. However, anemia can also be caused by blood loss and various underlying health conditions.