• Brain and nerve health: Vitamin B12 helps keep the brain and nerves healthy, and can help with cognitive functioning. 
• Red blood cell production: Vitamin B12 helps form red blood cells and prevents anemia. 
• DNA production: Vitamin B12 helps create and regulate DNA, the genetic material in all cells. 
• Homocysteine levels: Vitamin B12 helps lower levels of homocysteine, an amino acid linked to heart disease, stroke, and osteoporosis. 
• Megaloblastic anemia prevention: Vitamin B12 helps prevent megaloblastic anemia, a blood condition that causes weakness and tiredness. 
• Energy production: Vitamin B12 helps convert food into energy. 

People who may need vitamin B12 supplements include: 

Vegans and vegetarians
People who don’t eat animal products may not get enough vitamin B12 from their diet.

Older adults
People over 50 may not have enough stomach acid to absorb vitamin B12 from food.

People with certain conditions
People with conditions that affect their ability to absorb vitamin B12 may need supplements.

People with certain diseases
People with autoimmune diseases, Crohn’s disease, HIV, or pernicious anemia may need supplements. 

People who have had certain surgeries
People who have had stomach or intestinal surgery may not be able to absorb vitamin B12, including gastric bypass surgery.

Many medications can deplete vitamin B12, including: 

• Anti-seizure medications: These include phenytoin
• Chemotherapy medications: These include methotrexate.
• Bile acid sequestrants: These include colestipol (Colestid), cholestyramine (Questran), and colsevelam (Welchol), used to treat some types of IBD
• H2 blockers: These include cimetidine, famotidine, and ranitidine (Zantac).
• Proton pump inhibitors (PPIs): These include omeprazole, lansoprazole, rabeprazole and esomeprazole.
• Metformin: This is a diabetes drug that can reduce the body’s ability to absorb vitamin B12.
• Oral birth control pills: These can cause low levels of vitamin B12.
• Antibiotics, including:
  • Aminoglycosides
  • Sulfa drugs
  • Cephalosporins
  • Macrolides
  • Penicillin derivatives
  • Quinolones
  • Tetracycline derivatives

I will provide more detailed aftercare advice and a patient information leaflet at your appointment.