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Understanding Vitamin B12 Deficiency Anemia: Causes, Symptoms, and Treatment

Alan Lucks | MD

Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on July 5th, 2023.

Key Takeaways

  • This condition occurs when blood levels drop below 200 pg/mL (normal range 300-900 pg/mL), causing the body to produce fewer but abnormally large red blood cells that can't carry oxygen effectively.

  • Pernicious anemia, an autoimmune condition affecting 1-2% of adults over 60, destroys stomach cells that produce intrinsic factor—a protein essential for B12 absorption in the small intestine.

  • Neurological symptoms like tingling hands, balance problems, and memory issues can become permanent if untreated for over 6 months, even after B12 levels normalize.

  • Adults need only 2.4 micrograms daily, but those with absorption problems require 1,000 microgram injections monthly or 1,500 microgram oral doses since only 1-5% gets absorbed without intrinsic factor.

  • Strict vegans develop deficiency within 2-5 years since B12 exists almost exclusively in animal products, while people taking metformin or acid-blocking medications face gradual depletion over time.

Vitamin B12 deficiency anemia is a condition where your body lacks enough healthy red blood cells due to low levels of vitamin B12. Red blood cells are essential for transporting oxygen throughout your body. When you don't have enough of them, your body doesn't get the oxygen it needs to function properly, leading to symptoms like fatigue, weakness, and shortness of breath.

Causes of Vitamin B12 Deficiency Anemia

There are several reasons why you might develop vitamin B12 deficiency anemia:

  • Not getting enough vitamin B12 from your diet, especially if you're older or follow a vegetarian diet

  • Having an autoimmune disease that attacks the cells in your stomach that produce intrinsic factor, a protein that helps your body absorb vitamin B12 (pernicious anemia)

  • Undergoing surgery to remove part of your stomach or intestines

  • Having a disease that affects nutrient absorption in your intestines, such as Crohn's disease or HIV

  • Taking certain medications, like antibiotics or anti-seizure drugs

  • Being infected with a tapeworm

Symptoms of Vitamin B12 Deficiency Anemia

If you have vitamin B12 deficiency anemia, you may experience the following symptoms:

  • Fatigue and weakness

  • Shortness of breath

  • Pale or yellow skin

  • Dizziness

  • Loss of appetite and weight loss

  • Numbness or tingling in hands and feet

  • Rapid heartbeat or chest pain

  • Muscle weakness

  • Mood changes, confusion, or forgetfulness

If you experience any of these symptoms, it's important to see your doctor for a proper diagnosis. They may perform tests such as a complete blood count, vitamin B12 level test, intrinsic factor antibody test, Schilling test, or methylmalonic acid level test to determine if you have vitamin B12 deficiency anemia.

Understanding Vitamin B12 Deficiency Anemia: Causes, Symptoms, and Treatment

Treatment for Vitamin B12 Deficiency Anemia

The good news is that vitamin B12 deficiency anemia is usually easy to treat with diet and vitamin supplements. To increase your vitamin B12 intake, you can:

  • Eat more foods rich in vitamin B12, such as beef, liver, chicken, fish, shellfish, fortified breakfast cereals, low-fat milk, yogurt, cheese, and eggs

  • Take vitamin B12 supplements in the form of pills or a nasal spray

  • Receive high-dose vitamin B12 shots if your levels are very low

In addition to increasing your vitamin B12 levels, your doctor may also treat the underlying condition causing your anemia. It's crucial to address vitamin B12 deficiency anemia promptly, as long-term deficiency can lead to damage to your heart, brain, nerves, bones, and other organs. With proper treatment, you should feel better and avoid any long-term complications.

For more information on vitamin B12 deficiency anemia, consult the following resources:

The Bottom Line

Early detection and treatment can fully reverse this anemia and prevent permanent nerve damage, but neurological symptoms may persist if treatment is delayed beyond 6 months. The key is recognizing subtle early signs like fatigue combined with tingling extremities, especially in older adults or those with dietary restrictions. If you're experiencing these symptoms, Doctronic can help you understand your risk factors and next steps quickly.

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