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What happens to your body when you’re anemic?

Anemia is a condition in which you lack enough healthy red blood cells to carry adequate oxygen to your body’s tissues. Having anemia can make you feel tired and weak. There are many forms of anemia, each with its own cause. Anemia can be temporary or long term, and it can range from mild to severe.

What is anemia?

Anemia is a condition in which you don’t have enough healthy red blood cells to carry adequate oxygen to the body’s tissues. Having anemia can make you feel tired and weak. The most common symptom of anemia is fatigue.

When you’re anemic, your blood can’t carry enough oxygen to the rest of your body. Oxygen gives your body energy, so a lack of oxygen leads to fatigue. Blood is made up of plasma, white blood cells, platelets, and red blood cells. Red blood cells contain an iron-rich protein called hemoglobin, which carries oxygen from your lungs to the rest of your body. When you have anemia, you have fewer red blood cells than normal or your red blood cells don’t work properly.

There are more than 400 types of anemia, which are divided into three major groups:

  • Anemia caused by blood loss
  • Anemia caused by decreased or faulty red blood cell production
  • Anemia caused by destruction of red blood cells

What causes anemia?

The most common causes of anemia are:

  • Iron deficiency anemia – Iron deficiency anemia is the most common type of anemia overall and it has many causes, including bleeding, poor diet, intestinal diseases, intestinal surgery, pregnancy, and menstrual problems.
  • Vitamin deficiency anemia – In addition to iron, your body needs folate and vitamin B-12 to make enough healthy red blood cells. A diet lacking in these and other key nutrients can cause decreased red blood cell production.
  • Anemia of chronic disease – Certain diseases such as cancer, HIV/AIDS, rheumatoid arthritis, kidney disease, Crohn’s disease and other chronic inflammatory diseases can interfere with the production of red blood cells.
  • Aplastic anemia – This rare, life-threatening anemia occurs when your body doesn’t produce enough red blood cells. Causes include infections, certain medicines, autoimmune diseases, and exposure to toxic chemicals.
  • Hemolytic anemias – These anemias develop when red blood cells are destroyed faster than bone marrow can replace them. Certain blood diseases increase red blood cell destruction.

What are the symptoms of anemia?

Common anemia symptoms include:

  • Fatigue
  • Weakness
  • Pale or yellowish skin
  • Irregular heartbeats
  • Shortness of breath
  • Dizziness or lightheadedness
  • Chest pain
  • Cold hands and feet
  • Headache

Symptoms can be mild at first and worsen as anemia gets more severe. At its worst, anemia can cause heart problems and other potentially life-threatening complications.

How does anemia affect your body?

When you have anemia, your body doesn’t get enough oxygen-rich blood. This can have wide-ranging effects:

Less oxygen to organs and tissues

Red blood cells carry oxygen through your blood to all parts of your body. When oxygen levels drop, you may notice symptoms in specific body parts. For example, anemia can cause:

  • Fatigue and shortness of breath from inadequate oxygen to muscles
  • Rapid or irregular heartbeats from oxygen deprivation in heart muscle
  • Pale skin from less blood flow
  • Dizziness or headaches from oxygen deprivation in the brain

Impaired immune function

Oxygen plays an important role in immune system function. Anemia hampers your body’s ability to fight infections. People with anemia are more likely to get colds and flu.

Slow wound healing

Red blood cells deliver oxygen and nutrients that are important for proper tissue and wound healing. Without enough oxygen-rich blood, wound healing slows down.

Growth problems

Oxygen and nutrients carried in red blood cells are essential for normal growth and development in children. Anemia that starts early in childhood or lasts a long time can lead to slowed growth and developmental delays.

Gastrointestinal effects

The gastrointestinal tract may be affected in some types of anemia. Examples include:

  • Poor appetite or overeating unusual substances like ice, dirt, or clay (pica) from iron deficiency
  • Constipation from sluggish GI tract function
  • Diarrhea or blood in stool from intestinal bleeding
  • Sore tongue or mouth sores from vitamin deficiencies

Reproductive issues

Anemia can also affect menstruation in women. Signs can include:

  • Absent or delayed periods from hormonal changes
  • Heavy periods from disrupted blood clotting
  • Increased risk of complications during pregnancy for women with severe anemia

Anemia affects men too and can cause decreased libido and erectile dysfunction.

How is anemia diagnosed?

A doctor will diagnose anemia based on your medical history, a physical exam, and test results, including:

Complete blood count (CBC)

This blood test measures the number of red blood cells, white blood cells, platelets, and the amount of hemoglobin in your blood. A low red blood cell count indicates anemia. The CBC provides information about the size and shape of your red blood cells that can help identify what’s causing the anemia.

Peripheral smear

Examining a sample of your blood under a microscope provides information about abnormalities in the size, shape, and color of your red blood cells.

Iron tests

These blood tests measure the amount of iron and iron-binding capacity in your blood. Low iron levels point to iron deficiency as the cause of anemia.

Vitamin deficiency tests

Checking levels of folic acid and vitamin B-12 can help diagnose megaloblastic anemia caused by not getting enough of these vitamins.

Other tests

Your doctor may order additional tests depending on your specific signs and symptoms. These could include tests for kidney function, infections, leukemia, bone marrow problems, and other disorders that can cause anemia.

What are the risk factors for anemia?

Factors that increase your risk of developing anemia include:

  • Poor diet. A diet low in iron, vitamin B-12 and folate increases risk of nutritional deficiencies that can cause anemia.
  • Intestinal disorders. Diseases that affect absorption of nutrients like Crohn’s disease or celiac disease make it harder to get enough iron and vitamins from food.
  • Menstruation. Heavy periods can lead to iron deficiency anemia in women.
  • Pregnancy. Higher iron and nutrient needs during pregnancy increase anemia risk.
  • Chronic conditions. Many diseases like cancer, kidney failure, and rheumatoid arthritis are associated with a higher risk of anemia.
  • Bleeding. Losing blood from heavy periods or internal bleeding can cause anemia.
  • Genetics. Anemia is more common in people of African, Hispanic, and Asian descent.
  • Age. Older adults have a higher anemia risk due to poor diet and other age-related diseases.

How is anemia treated?

Treatment for anemia depends on the underlying cause:

Iron supplements

If iron deficiency is causing your anemia, your doctor may recommend iron pills or liquids. Vitamin C can help your body absorb iron. Taking iron with food can help reduce side effects like an upset stomach.

Folate and vitamin B-12

Supplements of folic acid and vitamin B-12 treat nutritional deficiency anemias. Food sources include citrus fruits, dark green vegetables, and dairy for vitamin B-12.

Erythropoiesis-stimulating agents (ESAs)

These man-made forms of erythropoietin, a hormone produced by the kidneys, can stimulate bone marrow to produce more red blood cells. ESAs treat anemia caused by chronic kidney disease and chemotherapy.

Blood transfusions

A blood transfusion to boost red blood cell levels quickly may be needed in life-threatening or severe anemia. Transfusions carry some risks like allergic reactions and iron overload.

Medications or surgery

If an underlying condition like an ulcer, fibroid tumors, or autoimmune disease causes anemia, treatment will focus on resolving that disorder. This may include medications or procedures like endoscopic surgery.

Diet changes

Eating more iron and vitamin-rich foods can help in cases of mild nutritional anemia. Your doctor may refer you to a dietitian to ensure you get enough nutrients.

What foods are good for anemia?

The best diet for anemia includes foods containing the nutrients your body needs to produce healthy red blood cells:

Iron-rich foods

  • Meat like beef, pork, and chicken liver
  • Seafood like oysters, mussels, and sardines
  • Beans, lentils and soybeans
  • Dark, leafy greens like spinach and kale
  • Raisins and prunes
  • Iron-fortified breads and cereals

Eating foods high in vitamin C like citrus fruits, tomatoes, and broccoli improves iron absorption from plant sources.

Folate-rich foods

  • Legumes like black-eyed peas, pinto beans and lentils
  • Green vegetables like asparagus, spinach and mustard greens
  • Oranges and orange juice
  • Nuts and sunflower seeds
  • Eggs
  • Grains like quinoa, rice and oats

Vitamin B-12 foods

  • Beef and chicken liver
  • Fish like salmon, trout and tuna
  • Eggs and dairy products like milk, cheese and yogurt
  • Fortified breakfast cereals
  • Nutritional yeast

Ask your doctor or dietitian for personalized meal plans and dietary supplement recommendations for your specific type of anemia.

What are the complications of anemia?

Mild anemia often causes no complications. But left untreated, anemia can worsen and lead to serious health problems like:

Heart problems

Anemia strains your heart and blood vessels to deliver more oxygen. Over time, this increased workload can cause an irregular heartbeat called an arrhythmia, a heart murmur from damaged heart valves, an enlarged heart, or even heart failure.

Pregnancy complications

Pregnant women with severe anemia are more likely to have a premature birth and deliver a low-birth-weight baby.

Delayed growth in infants and children

Without adequate oxygen and nutrients from red blood cells, babies and children show slowed or stunted growth and cognitive development.

Severe infections

Low red blood cell counts impair your immune system. Anemia from any cause raises the risk of potentially life-threatening infections.

Worsening of chronic conditions

Anemia worsens symptoms of many disorders like congestive heart failure, diabetes, asthma and rheumatoid arthritis.


Rarely, extreme anemia can cause shock from lack of blood flow and be fatal. Death is most likely with anemia from acute blood loss or aplastic anemia when the bone marrow stops producing blood cells.

Can anemia be prevented?

You may be able to reduce your anemia risk by:

  • Eating foods high in iron, vitamin B-12 and folate like meat, seafood, leafy greens, beans, eggs, dairy, citrus fruits, and fortified grains
  • Treating underlying conditions, like celiac disease or a bleeding ulcer, that can cause anemia
  • Having an annual CBC as part of your routine health screening to catch anemia early
  • Starting prenatal vitamins with iron and folic acid before getting pregnant or as soon as you know you are pregnant
  • Avoiding medications like aspirin, ibuprofen, and anticoagulants that can irritate your stomach and cause bleeding

Consult your doctor if fatigue, weakness or other troubling symptoms arise so that prompt treatment can prevent complications of anemia.


Anemia develops when your blood lacks sufficient healthy red blood cells to carry oxygen to your body’s tissues. Many types of anemia exist, but all involve fatigue as a main symptom. Anemia can range from mild to severe. Without enough oxygen in your blood, many body parts and systems are affected including your heart, muscles, brain, immune system, gastrointestinal tract, and more. While mild anemia often causes no problems, severe or long-lasting anemia can result in serious complications. Diagnosing and treating the underlying cause, whether from bleeding, deficiencies, or disease, can restore red blood cell levels and oxygenation. Eating an iron, folate and vitamin B-12 rich diet and treating related medical conditions may help prevent some cases of anemia.