Anemia B12: vitamin B12 deficiency symptoms, causes, treatment

Medically reviewed: 7, January 2024

What is Anemia B12 (vitamin B12 deficiency anemia) and how to prevent it?

Anemia B12 or vitamin B12 deficiency anemia is a condition that occurs when your body does not have enough vitamin B12 to produce healthy red blood cells. Red blood cells are responsible for carrying oxygen from your lungs to all parts of your body. Without enough oxygen, your body cannot function properly and you may experience symptoms such as fatigue, weakness, dizziness, pale skin, shortness of breath, and heart palpitations.

Vitamin B12 is a nutrient that is mainly found in animal products, such as meat, eggs, dairy, and fish. It is also added to some fortified foods, such as breakfast cereals and nutritional yeast. Your body needs vitamin B12 to make DNA, maintain nerve health, and prevent a type of anemia called megaloblastic anemia. In this type of anemia, the red blood cells are abnormally large and oval-shaped, and they have trouble carrying oxygen.

Anemia B12 causes

There are several causes of vitamin B12 deficiency anemia, such as:

Poor diet

If you do not eat enough foods that contain vitamin B12, or if you follow a strict vegetarian or vegan diet, you may be at risk of developing vitamin B12 deficiency anemia. You may need to take vitamin B12 supplements or eat foods that are fortified with vitamin B12 to meet your daily needs.

Pernicious anemia

This is a condition that affects your stomach’s ability to produce a protein called intrinsic factor. Intrinsic factor is necessary for your intestines to absorb vitamin B12 from food. Pernicious anemia is caused by an autoimmune reaction, where your immune system mistakenly attacks the cells that make intrinsic factor. This condition is more common in people with a family history of the disease, or in people who have other autoimmune diseases, such as type 1 diabetes or thyroid disease.

Intestinal problems

Some diseases or surgeries that affect your intestines can interfere with your absorption of vitamin B12. For example, Crohn’s disease, celiac disease, gastric bypass surgery, or infection with tapeworms can reduce the amount of vitamin B12 that your body can use.

Medications that cause anemia B12

Some drugs can affect your body’s ability to absorb or use vitamin B12. For example, metformin, a medication for diabetes, can lower your vitamin B12 levels. Other drugs that can cause vitamin B12 deficiency include antibiotics, antacids, proton pump inhibitors, and nitrous oxide.

Anemia B12: How is vitamin B12 deficiency anemia diagnosed?

The diagnosis of vitamin B12 deficiency anemia is based on your symptoms, medical history, physical examination, and blood tests. Your doctor may check your levels of vitamin B12, folate, iron, and other blood cells. You may also need to have a test called a Schilling test, which measures how well your body absorbs vitamin B12.

Some of the blood tests that can help diagnose vitamin B12 deficiency anemia are:

• Complete blood count (CBC)

This particular examination evaluates the quantity and dimensions of your red blood cells, white blood cells, and platelets. A low red blood cell count, or a high mean corpuscular volume (MCV), which indicates the average size of your red blood cells, can suggest vitamin B12 deficiency anemia.

• Serum vitamin B12

This test checks the vitamin B12 levels in your blood, and a low result may indicate a deficiency. However, some people may have normal or borderline levels of vitamin B12, but still have symptoms of deficiency. Therefore, this test alone is not enough to diagnose vitamin B12 deficiency anemia.

• Serum folate

This test measures the amount of folate in your blood. Folate is another B vitamin that works together with vitamin B12 to make red blood cells. A low level of folate can also cause megaloblastic anemia, and it can mask the symptoms of vitamin B12 deficiency. Therefore, both vitamins need to be checked to rule out other causes of anemia.

• Serum methylmalonic acid (MMA) and homocysteine

These tests measure the levels of two substances that are affected by vitamin B12. MMA and homocysteine are normally converted into other compounds by vitamin B12. If vitamin B12 is deficient, MMA and homocysteine levels will rise in the blood. These tests are more sensitive and specific than serum vitamin B12, and can detect early or mild cases of vitamin B12 deficiency anemia.

• Intrinsic factor antibodies (IFA)

This test detects the presence of antibodies that target intrinsic factor, the protein that helps your body absorb vitamin B12. If you have these antibodies, it means you have pernicious anemia, which is the most common cause of vitamin B12 deficiency anemia. However, not all people with pernicious anemia have these antibodies, and some people without pernicious anemia may have them. Therefore, this test is not conclusive, but it can support the diagnosis of pernicious anemia.

How is vitamin B12 deficiency (Anemia B12) treated?

The treatment of vitamin B12 deficiency anemia depends on the cause and severity of your condition. The main goal of treatment is to increase your vitamin B12 levels and correct your anemia. This can be done by:

• Taking vitamin B12 supplements by mouth or by injection.

The dosage and frequency of vitamin B12 supplements will vary depending on your individual needs. You may need to take them for the rest of your life, or until your condition improves. Typically, when it comes to administering vitamin B12 injections, hydroxocobalamin is the preferred choice over cyanocobalamin due to its longer retention in the body. Vitamin B12 is also available as pills, liquids, tablets, nasal gels, or sprays.

• Eating more foods that are rich in vitamin B12, or choosing foods that are fortified with vitamin B12.

Some examples of foods that contain vitamin B12 are liver, clams, sardines, beef, eggs, milk, cheese, yogurt, and fortified cereals. You can also use nutritional yeast, which is a vegan source of vitamin B12, to sprinkle on your food or add to your recipes.

• Treating the underlying cause of your vitamin B12 deficiency, if possible.

For example, if you have pernicious anemia, you may need to take medications to suppress your immune system and prevent further damage to your stomach. If you have intestinal problems, you may need to have surgery or take medications to treat your condition. If you are taking drugs that affect your vitamin B12 levels, you may need to adjust your dosage or switch to a different medication.

The prognosis of vitamin B12 deficiency anemia is generally good, as long as you receive proper treatment and follow-up care. Most people can recover from their symptoms and restore their normal blood counts.

Anemia B12 complications

However, if left untreated, vitamin B12 deficiency anemia can cause serious complications, such as:

• Nerve damage.

Vitamin B12 is essential for the health of your nerves, and a lack of vitamin B12 can cause nerve damage, also known as neuropathy. This can lead to numbness, tingling, burning, or pain in your hands and feet. It can also affect your balance, coordination, and reflexes. In severe cases, nerve damage can cause paralysis, dementia, or psychosis.

• Heart problems.

Vitamin B12 deficiency anemia can affect your heart by increasing your risk of developing a condition called homocysteinemia. This is when you have high levels of a substance called homocysteine in your blood, which can damage your blood vessels and increase your risk of blood clots, stroke, and heart attack.

• Birth defects.

Vitamin B12 deficiency anemia can affect pregnant women and their unborn babies. A lack of vitamin B12 can cause miscarriage, premature birth, low birth weight, or birth defects, such as neural tube defects. Neural tube defects are when the baby’s brain and spinal cord do not develop properly, which can cause serious problems, such as spina bifida or anencephaly.

How can Anemia B12 (vitamin B12 deficiency) be prevented?

The prevention of vitamin B12 deficiency anemia is mainly based on eating a balanced diet that includes enough vitamin B12, or taking vitamin B12 supplements if you are at risk of deficiency.

You should also have regular check-ups with your doctor, especially if you have a condition or take a medication that can affect your vitamin B12 levels. If you notice any symptoms of vitamin B12 deficiency anemia, such as fatigue, weakness, dizziness, or pale skin, you should seek medical attention as soon as possible. Early diagnosis and treatment can help you avoid complications and improve your quality of life.