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Vitamin B12 deficiency: causes and treatment

A vitamin B12 deficiency refers to a condition where the body lacks an adequate amount of vitamin B12, a crucial water-soluble vitamin. This deficiency can occur when the body doesn't absorb enough vitamin B12 from the foods consumed or when there is a deficiency in the diet itself.

Vitamin B12 plays a vital role in various bodily functions, including the production of red blood cells, DNA synthesis, nerve function, and the maintenance of a healthy nervous system. When there is a deficiency, it can lead to various health issues, such as anemia (a decrease in red blood cells), fatigue, weakness, neurological problems, tingling sensations, and even more severe complications if left untreated.

For concerns related to a vitamin B12 deficiency, it's advisable to consult the following health care professionals:

  • Primary care physician: Your first point of contact should be your primary care physician. They can assess your symptoms, medical history, and order blood tests to determine your B12 levels. They will guide you on appropriate treatment options or refer you to a specialist if needed.

  • Hematologist: If your deficiency is severe or related to conditions like pernicious anemia, a hematologist (a specialist in blood disorders) can provide specialized care and treatment.

  • Gastroenterologist: If you have gastrointestinal issues affecting nutrient absorption, a gastroenterologist can diagnose and manage these conditions, which might be contributing to your B12 deficiency.

  • Dietitian or nutritionist: A registered dietitian can help you plan a diet that includes B12-rich foods and ensure you're meeting your nutritional needs. They can also guide you on appropriate supplements if necessary.

  • Endocrinologist: If your B12 deficiency is related to another underlying health condition, such as diabetes or thyroid disorders, an endocrinologist can provide comprehensive care.

  • Neurologist: If you're experiencing neurological symptoms, such as tingling or numbness, a neurologist can evaluate and manage these issues.

  • OB/GYN: Pregnant or breastfeeding women should consult their OB/GYN to ensure adequate B12 intake for both maternal and fetal health.


Vitamin B12 deficiency causes

A vitamin B12 deficiency can stem from several underlying causes, leading to insufficient levels of this essential nutrient in the body. These causes include:

  • Dietary factors

  • Pernicious anemia

  • Gastrointestinal disorders

  • Surgical interventions

  • Medications

  • Increased age

  • Parasitic infections

  • Alcoholism

  • Genetic factors

  • Malnutrition


Vitamin B12 deficiency symptoms and signs

  • Fatigue

  • Anemia

  • Nervous system issues

  • Cognitive impairment

  • Mood changes

  • Digestive problems

  • Smooth tongue

  • Yellowing of the skin

  • Vision disturbances

  • Heart palpitations

  • Canker sores

  • Hair and nail changes

  • Muscle weakness


Vitamin B12 deficiency treatment

Treating a vitamin B12 deficiency involves addressing the underlying cause and replenishing the body's B12 levels. Depending on the severity of the deficiency and the specific cause, treatment options include:

  • Dietary changes: Increasing intake of B12-rich foods, such as meat, fish, poultry, dairy products, eggs, and fortified cereals.

  • Oral supplements: Taking vitamin B12 supplements, usually in the form of cyanocobalamin, can effectively raise B12 levels. Dosage recommendations vary and should be determined by a healthcare professional.

  • Injections: For severe deficiencies or cases where oral absorption is compromised, B12 injections may be prescribed. These injections deliver a higher dose of B12 directly into the bloodstream.

  • Nasal spray: A B12 nasal spray might be recommended for individuals who have difficulty swallowing pills or have absorption issues.

  • Intravenous (IV) Therapy: In rare cases of severe deficiency or certain medical conditions, B12 may be administered intravenously under medical supervision.

  • Treat underlying conditions: Treating conditions like pernicious anemia or gastrointestinal disorders that contribute to the deficiency.

  • Lifestyle changes: Reducing alcohol consumption, quitting smoking, and managing stress can support B12 absorption.

  • Supervised monitoring: Regular follow-up with a health care professional to monitor B12 levels and adjust treatment as needed.


It's essential to seek medical guidance for proper diagnosis and treatment. Self-diagnosis and treatment can lead to ineffective results and potential health risks. A St. Joseph Health primary care provider can determine the appropriate treatment plan based on individual needs and circumstances.

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