Does alcohol abuse cause vitamin B12 deficiency?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: May 1, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the FDA Drug Label

Colchicine para-aminosalicylic acid and heavy alcohol intake for longer than 2 weeks may produce malabsorption of vitamin B12.

  • Alcohol abuse can lead to malabsorption of vitamin B12, which may cause low B12 levels.
  • The drug label directly states that heavy alcohol intake can produce malabsorption of vitamin B12, implying a causal relationship between alcohol abuse and low B12 levels 1.

From the Research

Alcohol abuse is a significant cause of low vitamin B12 levels, and supplementation is essential to prevent morbidity and mortality. The relationship between alcohol abuse and vitamin B12 deficiency is well-established, with chronic alcohol consumption damaging the lining of the stomach and intestines, impairing B12 absorption 2. Alcohol also interferes with the intrinsic factor needed for B12 absorption and can cause inflammation of the pancreas, further hindering nutrient absorption. Additionally, alcoholics often have poor diets lacking in B12-rich foods like meat, eggs, and dairy products. Low B12 can lead to anemia, neurological problems, and fatigue. Some key points to consider in the management of vitamin B12 deficiency include:

  • Screening average-risk adults for vitamin B12 deficiency is not recommended, but screening may be warranted in patients with one or more risk factors, such as gastric or small intestine resections, inflammatory bowel disease, or use of certain medications 3.
  • Initial laboratory assessment should include a complete blood count and serum vitamin B12 level, and measurement of serum methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low-normal levels of vitamin B12 3.
  • Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms, but intramuscular therapy leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms 3.
  • Treatment typically involves B12 supplementation (1000 mcg daily orally or monthly injections of 1000 mcg) along with addressing the underlying alcohol use disorder. For those with alcohol-related B12 deficiency, supplementation should continue during alcohol treatment, and a balanced diet should be emphasized once sobriety is established. Blood tests can monitor B12 levels to ensure they return to normal range (200-900 pg/mL). It is also important to note that the oral route is comparable to the intramuscular route for rectifying vitamin B12 deficiency 4.

References

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.