What Causes Anemia?

Health Line

5 hours ago

Anemia may develop from having too few red blood cells or too little hemoglobin, the iron-rich protein that carries oxygen to all of your organs.
Anemia is a signal that your body's capacity to transport oxygen to every organ has been compromised. This can cause unsettling symptoms like fatigue and breathlessness.
Anemia can result from multiple and overlapping disruptions to your body's natural cycles and processes, especially in the making, carrying, and recycling of red blood cells.
Acute anemia often results from unexpected or rapid blood loss. Chronic forms of anemia may develop gradually and have multiple causes.
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:
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
»Learn more: How to increase red blood cell count
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.