What Causes Anemia?

Common causes of anemia

The most common causes of chronic anemia include:

Your body isn’t making enough red blood cells

Your body needs certain nutrients — especially iron, vitamin B12, and folate — to build healthy red blood cells. If you don’t get enough of these nutrients, or if your body can’t use them properly, red blood cell production slows down.

Iron deficiency

The most common cause of anemia is not having enough iron in your body. This can happen if you’re not eating enough iron-rich foods, or if your body has trouble absorbing or holding on to the iron you do eat.

When there isn’t enough iron in the blood, your body cannot make enough hemoglobin. This protein in red blood cells carries oxygen.

As a result, your red blood cells may be smaller and lighter in color than usual, and some organs that need oxygen the most, like your brain and heart, may not be able to work as expected.

Causes of iron deficiency anemia may include:

• not eating enough iron-rich foods
• having heavy menstrual periods
• experiencing gradual blood loss from ulcers or polyps in the stomach or intestines
• living with conditions that block iron absorption, like celiac disease

Vitamin B deficiency

Your body also needs vitamin B12 and folate (a type of vitamin B) to make red blood cells. Without these vitamins, the bone marrow creates cells that are too large and don’t work properly.

Vitamin B12 deficiency anemia, also known as megaloblastic anemia, can cause symptoms like fatigue and weakness. It may also manifest with hand or foot numbness or memory challenges.

Causes of vitamin B deficiency may include:

• not eating enough animal products
• living with digestive conditions where the body can’t absorb vitamin B12
• taking certain medications that interfere with nutrient absorption
• being pregnant
• having digestive diseases that affect folate levels

Your body is losing blood

Another common cause of anemia is that the body loses red blood cells faster than it can create new ones. This can result from a single event (like surgery or an accident) or slowly over time. It is related to the above cause of nutrient deficiency.

The most common causes of blood loss that lead to anemia include:

• heavy menstrual periods
• stomach or intestinal bleeding
• internal bleeding from injuries or surgery
• bleeding disorders, like hemophilia or persistent nosebleeds
• frequent blood donations without giving your body time to catch up

Your body is destroying red blood cells too early

Red blood cells usually live for 120 days. After that, your body replaces them. But sometimes, the immune system or living with specific conditions may lead your body to destroy red blood cells when they are still young.

When this happens, your body may not have time to make enough new red blood cells, and this can lead to a type of anemia known as hemolytic anemia.

Hemolytic anemia isn’t as common as nutrient deficiency anemia, but it may become more serious.

Common causes of hemolytic anemia may include:

• autoimmune conditions in which the body attacks its own red blood cells
• systemic infections
• inherited conditions, like sickle cell disease or thalassemia
• toxin poisoning
• side effects of medications

Your body is fighting a long-term condition

Some health conditions may make it harder for your body to produce healthy red blood cells.

Anemia of chronic disease or anemia of inflammation is common in people with:

• kidney disease
• cancer
• diabetes
• HIV
• rheumatoid arthritis
• lupus

Chronic inflammation makes your liver produce a hormone called hepcidin, which interferes with your body’s ability to move stored iron into the bloodstream. Your iron reserves live mostly in the liver. So, when your liver doesn’t release enough iron, your red blood cell production decreases, even if you are not low in iron.

This type of anemia may develop gradually and not cause evident symptoms at first.

Your bone marrow isn’t working properly

Red blood cells are made in the bone marrow (tissue inside your bones). Problems with the marrow mean your body can’t produce as many red blood cells as it needs. This is a rare but serious occurrence.

Conditions that may affect the health of your bone marrow include:

• myelodysplastic syndromes, where the bone marrow produces cells that don’t work well
• blood cancers, like leukemia
• cancer therapy, like chemotherapy and radiation therapy

What increases your chances of anemia?

Anyone can develop anemia, but some people may have a higher chance of developing it based on their health, age, sex, and lifestyle.

You may be at a higher risk of anemia if you:

• menstruate, and especially if your periods are heavy and prolonged
• are pregnant, because your body needs more iron and vitamins to support your baby’s development
• are still developing mentally and physically, because the body needs more nutrients during childhood and adolescence
• are an older adult, especially over the age 65, because nutrient absorption is more likely to be compromised
• are vegan or vegetarian
• have had surgery, especially stomach or intestinal procedures
• live with a chronic disease
• take medications, like acid reducers, chemotherapy, or seizure drugs
• have a family or personal history of blood disorders
• have intestinal parasites
• have had major blood loss

Takeaway

The main causes of anemia include nutrient deficiency (mostly iron and vitamin B) and impaired red blood cell production.

Anemia responds to treatment, and the first step to management is identifying the root cause. A healthcare professional may want to gather more information about your medical history and perform tests, like bloodwork.

If you experience persistent symptoms like unexplained fatigue, dizziness, shortness of breath, and heart palpitations, consider seeking medical care for testing. A primary care physician can help with the first steps.