Anemia: Everything You Need To Know

What is anemia?

Anemia is a common condition that affects many people around the world. It occurs when your body’s healthy red blood cells are deficient or there aren’t enough of them, stopping them from doing their job.

Red blood cells play a critical role in your body. They carry oxygen to the cells in vital organs and tissues, keeping them healthy and functional. Red blood cells also carry hemoglobin, a protein that binds with oxygen so it can be transported throughout the body. Anemia can occur when the oxygen distribution process is stopped or limited for some reason.

The condition’s symptoms and severity are different for everyone — you could feel slightly tired or experience more serious symptoms, like shortness of breath.

Anemia is most often associated with iron deficiency, but it can develop due to other causes and conditions.

Types of anemia include:

  • Vitamin deficiency anemia

  • Aplastic anemia

  • Hemolytic anemia

  • Anemia of inflammation or chronic disease

  • Sickle cell anemia

Anemia is more commonly associated with being biologically female due to pregnancy and menstruation. Other people, including those with dietary deficiencies, infections, cancer, intestinal disease, and other inflammatory conditions, also have more risk of developing anemia.

Statistics

Anemia is an important global issue. Here are some stats:

  • In 2019, an estimated 1.74 billion people¹ were affected by this condition worldwide — approximately 22.8% of the global population.

  • In the US, an estimated 5.6%² of people experience anemia.

  • About 10%³ of American women of childbearing age are affected by anemia because of menstruation.

  • 9% of children between 12 and 36 months are iron-deficient, and a third will go on to develop anemia.

Symptoms

Speak to your doctor and request blood work to determine if you’re anemic. You might not know you have the condition since mild anemia does not always cause symptoms.

Symptoms are more likely as anemia progresses. They often mimic nutrient deficiencies and other health conditions. This is why speaking to your doctor is essential, as it will help you understand your symptoms and get a diagnosis.

The most common anemia symptoms include:

  • Feeling tired

  • Muscle weakness

  • Dizziness or fainting

  • Restless legs

  • Shortness of breath, especially during exercise

  • Being less able to exercise 

Another symptom associated with iron-deficiency anemia, particularly in children, is an eating disorder called pica. People with pica may want to eat unusual non-food substances, such as ice, dirt, or chalk. Iron deficiency anemia is one of the most common causes of pica.

Complications

Anemia can usually be treated, but certain types can cause complications linked to the underlying cause. For example, heart and lung problems can occur with sickle cell anemia due to abnormally shaped red blood cells.

Any type of anemia can become more serious when left untreated. The blood’s ability to carry oxygen reduces as the number of functional red blood cells reduces. This means tissues don’t get enough oxygen to function properly. Chest pain, an irregular heartbeat, or even heart failure can occur in severe cases.

Pregnant women with anemia risk entering early labor and delivering babies with low birth weights.

Research¹ suggests premature infants are at risk of developing iron-deficiency anemia because they miss the opportunity to receive iron from their mothers during the third trimester. Anemia at a young age carries the risk of permanent cognitive delays.

Causes

Anemia typically occurs due to one of the following four issues:

  1. Not enough hemoglobin is being created for red blood cells to work correctly

  2. Hemoglobin in the red blood cells is not working correctly

  3. The body does not have enough red blood cells due to blood loss or insufficient production

  4. Red blood cells are being broken down too quickly

Within these four issues are the medical conditions that cause anemia.

Iron deficiency

Iron deficiency is the most common cause of anemia worldwide. It can occur due to insufficient dietary iron or poor iron absorption.

Iron is a critical component of hemoglobin, so when iron levels are low, not enough hemoglobin is made to form healthy red blood cells. This means fewer red blood cells are made from the bone marrow, and anemia develops. The red blood cells are also smaller.

Thalassemia

Thalassemia is a genetic blood condition that causes abnormal or low amounts of hemoglobin in the body. There are different types of thalassemia based on how hemoglobin chains are formed.

People with mild or “silent” thalassemia may not develop significant anemia or symptoms. People with severe anemia may experience fatigue, paleness, and shortness of breath.

Sickle cell disease

Sickle cell anemia, also known as sickle cell disease (SCD), is an inherited blood disorder generally diagnosed at birth.

SCD causes the red blood cells to have an irregular, curved, or C shape (like a sickle).

Sickled red cells have abnormal hemoglobin that cannot carry as much oxygen to the tissues, and they die early. This can lead to many serious health complications.

The sickled cells frequently get caught up in the circulation and block blood flow, causing tissues in the surrounding area to start dying. This can cause severe pain.

Aplastic anemia

Aplastic anemia is a rare disorder, but it can be serious. The condition occurs when bone marrow cannot produce enough healthy blood cells of all types: red blood cells, white blood cells, and platelets.

Certain blood diseases, viral infections, exposure to toxins like radiation, and using certain drugs can cause the disease.

This lack of blood cells leads to many challenges:

  • Not having enough red blood cells limits the amount of oxygen carried to the tissues and organs.

  • Not having enough white blood cells means the body is less able to fight infections.

  • Platelet levels that are too low mean the blood is too thin and doesn’t clot effectively, causing abnormal bleeding.

Aplastic anemia can lead to severe anemia, bleeding problems, and recurrent serious infections. The condition often resolves on its own, but it can be life-threatening.

Vitamin deficiency

A lack of some essential vitamins — especially vitamin B12 and folate — can cause vitamin-deficiency anemia. These vitamins are responsible for many critical bodily functions, including those of the nervous system.

Too little vitamin B12 and folate can also cause megaloblastic anemia. With this type of anemia, the red blood cells are large and abnormal; they cannot carry out their normal functions. They are removed from the bloodstream early, causing anemia.

Pernicious anemia is an autoimmune condition where the immune system attacks healthy stomach cells. This halts the natural absorption of vitamin B12.

Dietary deficiencies can occur if you have a poor diet and don’t consume the recommended daily amounts of vitamin B12 and folate. Certain medications can also affect vitamin absorption and cause dietary deficiencies.

Symptoms of vitamin B12 and folate deficiencies include:

  • Severe fatigue

  • Low energy levels

  • Muscle weakness

  • Mental health conditions, including depression

  • Challenges with memory and awareness

  • Mouth ulcers

  • Pins and needles

Blood loss

Blood loss can cause you to lose red blood cells. You might lose blood due to:

  • Menstruation, particularly with heavy periods

  • Gastrointestinal conditions, like celiac disease, ulcerative colitis, or even cancer — can damage the gut lining and cause blood loss over time

  • Surgery with severe blood loss

  • Trauma

  • Childbirth

Hemolytic anemia

The body naturally removes old red blood cells through a process called hemolysis. Hemolytic anemia occurs when there is too much hemolysis. This causes red blood cells to be removed from the bloodstream faster than the bone marrow produces them. Many conditions can cause this to happen, including autoimmune diseases, bone marrow issues, infections, inherited blood conditions, and certain medications.

Symptoms of hemolytic anemia include fatigue, dizziness, and weakness.

Hemolytic anemia can be mild or serious, depending on how much red cell hemolysis is occurring.

Medication and illness

The body may also break down red blood cells too quickly because of certain medications, including antibiotics.

Some health conditions can also cause red blood cells to break down too quickly, including high blood pressure and advanced stages of kidney and liver disease.

Inflammation or chronic disease

Anemia of inflammation or chronic disease (ACD) tends to occur with inflammation-causing conditions. It may develop over time.

Infections, cancer, kidney disease, and autoimmune diseases can all be linked to ACD.

ACD differs from other anemia types. In ACD, a person may have sufficient or even excess iron in the tissues but too little circulating in the bloodstream. Inflammation can prevent the body from transmitting stored iron to new red blood cells. The condition also results in less red blood cell production, and the cells have a shortened life span.

People with cancer can also develop anemia. ​​Blood loss, bone marrow, and chemotherapy are all factors.

Infectious diseases

Some infections can lead to anemia, including:

  • Malaria: Malaria reduces hemoglobin concentrations in both adults and children. Research indicates it’s a major cause of anemia in endemic areas. Many malaria deaths are directly or indirectly caused by anemia.

  • Hookworms. These parasites attach to and feed on the intestines. This causes blood loss which can lead to anemia.

  • Schistosomiasis: This is a parasitic disease. Its specific relationship with anemia is not fully understood but it also causes blood loss.

HIV is also linked to anemia.

The likelihood of experiencing infectious disease-related anemia is much higher for people living in rural areas in high-risk countries.

Childhood anemia

Around 20%¹ of children in the US will develop anemia at some point in their childhood.

The causes of anemia in children vary by age group. They include gastrointestinal blood loss, chronic diseases, infections, hemolysis, bone marrow conditions, and lead poisoning. Maternal anemia may also cause anemia in infants.

Nutritional factors can also play a role. One common reason for anemia in toddlers is excessive cow milk consumption. This causes calcium to inhibit the normal absorption of dietary iron in the digestive tract.

Risk factors

The following risk factors can raise your chance of developing anemia:

  • Heavy or prolonged menstrual periods — menstruation causes blood loss, which reduces your red blood cell count

  • Being pregnant — more iron and other nutrients are needed during pregnancy

  • Not consuming enough key nutrients, particularly iron, B12, and folate

  • Conditions such as celiac disease or pernicious anemia — can inhibit the absorption of key vitamins and minerals

  • Being 65 or older — approximately 10%² of Americans in this age group develop anemia

  • Heavy alcohol use and exposure to other substances — can deplete the body of key nutrients

  • Some medications, including non-steroidal anti-inflammatory drugs (NSAIDs) — can cause ulcers and gastrointestinal bleeding

  • Kidney disease, liver disease, autoimmune disease, cancer, or other chronic conditions — these conditions can reduce your red blood cell count

  • Having a family member with an inherited type of anemia (like thalassemia) can raise your chance of developing the condition

Diagnosis

Speak to your doctor if you suspect you have anemia, or you develop symptoms.

Anemia can be diagnosed in the following ways:

Complete blood count (CBC)

Your doctor will probably order blood work after they have taken your medical history. This will help identify anemia or another similar condition.

Bloodwork will typically include a complete blood count. This test will determine how many red blood cells (of all types) are in a blood sample. It will also provide a hemoglobin count.

Additionally, a CBC measures the red blood cell size, which can help determine the type of anemia. Small red blood cells occur in iron deficiency anemia, while larger cells are seen in B12 and folate deficiencies.

Other blood tests

Your doctor may order other tests to get a broader picture of your health and nutritional status. For example, they may order B12 and folate level tests, as well as liver, kidney, and endocrine function tests.

Depending on what condition your doctor suspects, they may order other tests.

Reticulocyte count

Reticulocytes are early-stage red blood cells. A reticulocyte count measures the number of reticulocytes in your blood. This can help diagnose serious health conditions that can lead to anemia, including liver, kidney, and bone marrow conditions.

Having too few or too many reticulocytes can indicate a problem. A low reticulocyte count is associated with bone marrow suppression, meaning insufficient red blood cells are produced. A high reticulocyte count may be found with hemolytic disorders (such as ​​sickle cell anemia), where red blood cells are produced at a higher rate to replace those being broken down.

Blood smear

A blood smear is a type of blood test used to assess the number and shape of blood cells of all types. A blood sample will be taken and sent to a lab where a technician will look at it through a microscope.

It can detect blood conditions that change how cells are formed, like sickle cell disease. It can also identify broken-down cells and help diagnose conditions like hemolytic anemia.

Treatments

There are various treatments for anemia. Your doctor will recommend treatment based on what’s causing your anemia. 

Anemia caused by blood loss

Treating the underlying cause of blood loss is essential. This may involve having a wound properly dressed, surgery, or taking medication.

You may need a blood transfusion to replenish the red blood cells in your body in serious cases.

Particularly in cases of long-term anemia from chronic medical conditions such as cancer or kidney failure, your treatment may involve stimulating red blood cell production in your bone marrow.

Anemia caused by bone marrow and stem cell conditions

Depending on its cause, aplastic anemia may be treated with immunosuppressant drugs or medications that stimulate red blood cell production.

Children with more severe anemia may need regular blood transfusions to maintain their red blood cell count. However, these can cause other complications, such as iron overload. Too much iron affects the liver, heart, and many other organs and systems.

Bone marrow transplants and gene therapy may also be used to treat anemia. However, they are considered a last resort because they can cause complications.

 Over the past few decades, scientists have researched¹ new treatment methods for anemia caused by bone marrow and stem cell conditions. These include stem cell transplants and gene therapy. However, these treatments are expensive and depend on many factors for their success.

Anemia caused by hemoglobin that doesn’t function properly

Sickle cell anemia can be treated with long-term drug therapy, commonly with hydroxyurea (Droxia, Siklos, or Hydrea). This helps prevent the red blood cells from sickling.

Your doctor may prescribe pain medication to help manage your symptoms and antibiotics to reduce the risk of infections.

In some rare cases, bone marrow or stem cell transplants are needed.

People with SCD typically need ongoing treatment and may develop complications later on. However, intervention is not always needed in mild cases.

Anemia caused by decreased or impaired red blood cells

Iron deficiency anemia is the most common type of anemia, and it’s generally the simplest to treat. Supplementation is usually the first-line therapy (with medical guidance) to ensure you are getting enough iron in your diet.

Vitamin deficiency anemia can be treated with supplementation and dietary changes as advised by your doctor.

If you have difficulty absorbing nutrients due to a chronic medical condition, your treatment plan will involve treating the condition and supplementing the vitamin. Your doctor may recommend vitamin B12 injections if you cannot absorb it orally.

Other anemia cases are treated depending on the cause. For example, some medications can stimulate the bone marrow to produce more red blood cells. Blood transfusions can also boost your red blood cell levels.

Anemia caused by red blood cell destruction

If your anemia is caused by the rapid destruction of your red blood cells, you’ll need to treat the underlying cause.

Hemolytic anemia treatment will depend on the cause: an autoimmune or infectious disease. Treatment can include blood transfusions, immunosuppressive medication, surgery, and stem cell transplant.

Anemia of chronic disease

Although several therapeutic options are available, there is no official treatment for ACD.

Treating the underlying condition — such as cancer, inflammatory bowel disease, a chronic infection, or other chronic conditions — is key. Treatment options include the following:

  • Blood transfusions: As a short-term therapy, blood transfusions can quickly boost the body’s hemoglobin levels. However, this carries the risk of infection or allergic reaction, so it’s not usually the first choice. Excess iron is a concern with repeated red blood cell transfusions, so they are not considered a long-term solution.

  • Stimulating red blood cell production: Medications can be injected that stimulate the bone marrow to produce red blood cells.

  • Medications: Your doctor may recommend other medications to treat an underlying condition.

  • Nutrition and supplementation: You’ll need to ensure your body gets enough of the vitamins and minerals it needs. Your blood levels of key nutrients will be monitored and your doctor will order routine lab testing. Working with a registered dietitian can help you treat and prevent anemia associated with certain medical conditions.

Prevention

Prevention depends on the type of anemia. Not all types of anemia can be prevented. For example, inherited anemia cannot be prevented but can be diagnosed and treated early. Early diagnosis and treatment may help forestall complications.

Some conditions are preventable with lifestyle changes and other therapeutic measures, including:

Proper nutrition

Eating a balanced diet with nutritious foods can help you consume the dietary iron and other nutrients you need to stay healthy.

Many foods contain iron, including green vegetables, legumes, red meat, and fortified bread, and cereals.

Food pairing is important, particularly when relying on plant-based iron sources. Iron absorption increases when you eat iron-containing foods with foods high in vitamin C, such as capsicum and oranges. However, iron absorption decreases when iron-containing foods are paired with calcium-rich foods, coffee, and polyphenols like those found in wine.

While iron deficiency is often associated with anemia, vitamin B12 and folate are important nutrients to consider. Vitamin B12-containing foods include fish, meat, eggs, and dairy products. Vegans should take a B12 supplement.

Folate-containing foods include dark green leafy vegetables, fruits, legumes, nuts, grains, seafood, eggs, dairy products, and meat.

Supplementation

Supplementing certain nutrients is another way to prevent anemia, particularly if your diet does not contain sufficient vitamin sources or you cannot absorb them effectively.

Supplementation is also important when demand increases. This occurs during pregnancy, with certain chronic conditions, or when nutrient stores are low.

Iron

The recommended daily iron intake varies from person to person.

According to the National Institutes of Health¹ (NIH), men aged 19 to 50 need 8mg daily, while women of the same age need 18mg daily. Pregnant women, those over 50 years of age, and children all have different needs.

Supplementing your diet with iron without first having a blood test is not recommended. It is possible to consume too much iron, and the required doses vary significantly. Long-term excess iron intake can cause many health effects, including liver disease, heart issues, fatigue, and hair loss.

Timing is also important, especially if you consume foods that inhibit iron absorption.

Supplementation will depend on your dietary intake of iron, the cause of your anemia, and your blood test results. For these reasons, only take iron supplements in consultation with your doctor.

B12 and folate

Most adults need 2.4–2.8mcg² of vitamin B12 and 400–600mcg³ of folate daily.

Consult your doctor before supplementing B12 and folate. They may recommend speaking to a registered dietitian.

Preventing aplastic anemia

It’s not possible to prevent aplastic anemia, a condition where the bone marrow cannot produce enough healthy blood cells. However, you can avoid potential causes, such as exposure to toxic chemicals, insecticides, and herbicides.

Other ways to prevent anemia

You can prevent anemia in other ways, including:

Avoid excessive alcohol intake

Alcohol and other substances can negatively impact your blood cells and how they function. Heavy alcohol consumption can suppress red blood cell production and cause cells to be destroyed too quickly, leading to anemia.

Minimize your alcohol consumption to avoid negative effects. The Dietary Guidelines for Americans, 2020–2025⁴ recommend adults should limit their intake of alcohol to two drinks per day for men and one drink per day for women.

Test for lead

Lead exposure is known to cause anemia. Researchers⁵ believe lead increases the rate at which red blood cells are destroyed. Lead may also impair hemoglobin production.

Some household items present a significant risk of lead exposure. It is most commonly found in glazed ceramics used to make dishware, particularly when they are antique, handcrafted, or imported.

You can have household items tested by a professional to learn if they contain lead.

  1. Iron | NIH: National Institute of Health

  2. Vitamin B12 | NIH: National Institute of Health

  3. Folate | NIH: National Institute of Health

  4. Dietary guidelines for Americans, 2020-2025 (2020)

  5. Relation between anemia and blood levels of lead, copper, zinc and iron among children (2010)

Doctors & specialists

Speak to your doctor if you develop any characteristic anemia symptoms, including fatigue, weakness, and breathlessness.

Anemia symptoms mimic many other nutrient deficiencies and medical conditions, so speaking to a medical professional and getting diagnosed is essential.

If you think you have anemia, speak to your primary care doctor in first instance. Most cases of iron deficiency anemia can be treated with supplements and dietary changes within a few months.

If your anemia is severe, ongoing, or does not respond to treatment, your doctor may refer you to a hematologist. A hematologist is a specialist physician who treats conditions related to the blood and blood-producing organs.

You may need to see other specialists help treat underlying conditions, such as cancer, autoimmune disease, or a long-term infectious disease.


Clinical trials for anemia

Actively recruiting
A Study of Etavopivat in Adults and Adolescents With Sickle Cell Disease (HIBISCUS)
AL, AR, AZ, CA and 20 more locations (US)
Actively recruiting
Efficacy and Safety of M281 in Adults With Warm Autoimmune Hemolytic Anemia
CA, CO, FL, IL and 9 more locations (US)
Actively recruiting
A Phase II Dose-escalation Study Characterizing the PK of Eltrombopag in Pediatric Patients With Previously Untreated or Relapsed Severe Aplastic Anemia or Recurrent Aplastic Anemia
AR, AZ, CA, CO and 14 more locations (US)