Vitamin B12 (Cobalamin)

What is Vitamin B12 (Cobalamin)? A water-soluble B vitamin that is essential to produce red blood cells, nervous system health, DNA and energy production. It is found only in animal-based foods and requires stomach acid for absorption.

Function

Role of Vitamin B 12

 

Red Blood Cell Formation

Prevents anemia

Brain and Nerve Health

Supports memory and cognition

DNA Synthesis

Works with folate in cell division and repair

Heart Health

Helps regulate homocysteine, lowering cardiovascular risk

Energy Metabolism

Supports mitochondrial function and reduces fatigue

 
Too Little Vitamin B12 (early signs are often neurological and can be irreversible):
  • Fatigue, weakness, pale skin
  • Tingling, numbness, neuropathy
  • Memory problems, confusion, mood changes
  • Tongue inflammation
  • Anemia
Groups at Risk of Deficiency:
  • Vegans, vegetarians
  • Older adults
  • Gastrointestinal disorders like Chron’s, celiac
  • Gastric surgery patients
  • Pernicious anemia
Too Much Vitamin B12:
  • No established upper limit from food – generally safe
  • High doses from injections/supplements may cause rashes, lab test interference
Just Right (adults):
  • 2.4 micrograms/day

 

Medication Interactions

(consult your doctor)

  • Gastric acid inhibitors (omeprazole, lansoprazole, cimetidine, ranitidine)
  • Metformin (diabetes treatment)

 

Food Sources

Animal
  • Beef (especially liver) – one of the richest sources
  • Fish/Clams
  • Poultry
  • Dairy
  • Egg yolks
Fortified
  • Plant based – nutritional yeast, cereals, non-dairy milk

Cooking tip:

Vitamin B12 is heat-stable, so cooking meats and dairy does not significantly reduce its content.

Reference:  Vitamin B12 – Health Professional Fact Sheet