Vitamin B₁₂ Deficiency

Vitamin B₁₂, also known as cobalamin, is an essential nutrient that plays a vital role in brain function, nerve tissue health, and the production of red blood cells. A deficiency in this critical vitamin can lead to a host of health problems. Here's what you need to know about Vitamin B₁₂ deficiency. ^[1]

Causes

The body cannot produce Vitamin B₁₂, so it must be obtained from animal-based foods or supplements. The most common causes of Vitamin B₁₂ deficiency include:

Inadequate Dietary Intake: Vegetarians, vegans, and older adults are at higher risk since plant-based diets are generally low in Vitamin B₁₂.
Malabsorption Issues: Certain conditions, such as pernicious anemia, celiac disease, or Crohn's disease, can hinder the absorption of Vitamin B₁₂ from food.
Medication Interference: Some medications, including proton pump inhibitors for acid reflux and metformin for diabetes, may reduce the absorption of Vitamin B₁₂.
Gastric Surgery: Weight loss surgeries that involve the removal of part of the stomach or the end of the small intestine can lead to a deficiency.

Symptoms

The symptoms of Vitamin B₁₂ deficiency can be subtle and may take years to manifest, which includes:

Fatigue and Weakness: Due to reduced red blood cell production, leading to less oxygen transport to the body's cells.
Neurological Changes: Numbness or tingling in the hands and feet, balance problems, depression, memory loss, and behavioral changes.
Gastrointestinal Issues: Nausea, constipation, loss of appetite, and weight loss.
Anemia: Characterized by pale or jaundiced skin, Vitamin B₁₂ deficiency can result in megaloblastic anemia.

Diagnosis and Management

Vitamin B₁₂ deficiency is diagnosed based on medical history, a physical examination, and blood tests to measure levels of Vitamin B₁₂, folate, and other parameters.

Management includes:

Dietary Changes: Incorporating B₁₂-rich foods like meat, eggs, dairy, and fortified cereals can help prevent and address deficiency.
Supplements: Oral B₁₂ supplements or fortified foods can be an effective treatment, particularly for individuals with dietary restrictions.
Injections: For severe deficiency or absorption issues, Vitamin B₁₂ injections may be necessary to bypass the digestive system.

Prevention and Outlook

Preventive measures include regular dietary intake of B₁₂-rich foods or supplements, especially for high-risk groups. Most people with Vitamin B₁₂ deficiency improve with appropriate treatment, though some neurological symptoms can become permanent if the deficiency is not corrected promptly.

Regular monitoring and early intervention are key to managing Vitamin B₁₂ deficiency effectively, ensuring a positive outcome for those affected by this condition.

↑ Langan RC & Goodbred AJ: Vitamin B12 Deficiency: Recognition and Management. Am Fam Physician 2017. (PMID 28925645) [PubMed] Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. Screening average-risk adults for vitamin B12 deficiency is not recommended. Screening may be warranted in patients with one or more risk factors, such as gastric or small intestine resections, inflammatory bowel disease, use of metformin for more than four months, use of proton pump inhibitors or histamine H2 blockers for more than 12 months, vegans or strict vegetarians, and adults older than 75 years. Initial laboratory assessment should include a complete blood count and serum vitamin B12 level. Measurement of serum methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low-normal levels of vitamin B12. Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms. Intramuscular therapy leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms. Absorption rates improve with supplementation; therefore, patients older than 50 years and vegans or strict vegetarians should consume foods fortified with vitamin B12 or take vitamin B12 supplements. Patients who have had bariatric surgery should receive 1 mg of oral vitamin B12 per day indefinitely. Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline.

[pmid28925645-1] Langan RC & Goodbred AJ: Vitamin B12 Deficiency: Recognition and Management. Am Fam Physician 2017. (PMID 28925645) [PubMed] Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. Screening average-risk adults for vitamin B12 deficiency is not recommended. Screening may be warranted in patients with one or more risk factors, such as gastric or small intestine resections, inflammatory bowel disease, use of metformin for more than four months, use of proton pump inhibitors or histamine H2 blockers for more than 12 months, vegans or strict vegetarians, and adults older than 75 years. Initial laboratory assessment should include a complete blood count and serum vitamin B12 level. Measurement of serum methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low-normal levels of vitamin B12. Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms. Intramuscular therapy leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms. Absorption rates improve with supplementation; therefore, patients older than 50 years and vegans or strict vegetarians should consume foods fortified with vitamin B12 or take vitamin B12 supplements. Patients who have had bariatric surgery should receive 1 mg of oral vitamin B12 per day indefinitely. Use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline.

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Causes

Symptoms

Diagnosis and Management

Prevention and Outlook

See Also