Vitamin B12 Food Sources
Vitamin B12 is found exclusively in animal-derived foods, with meat, fish, poultry, eggs, milk, and dairy products being the primary dietary sources. 1, 2
Primary Animal-Based Sources
Meat and Organ Meats:
- Red meat (beef, pork, lamb), poultry (chicken, turkey), and organ meats (liver, kidney) are excellent sources of vitamin B12 3, 2
- Liver and kidney contain the highest concentrations of B12 among all food sources 4
- Dark meats like tuna and red meat provide higher amounts compared to white meats 3
Fish and Shellfish:
- Fish and shellfish are rich sources, with bioavailability from fish meat averaging 42% 5, 6
- Fish also provides additional nutrients including vitamin D, iodine, selenium, and long-chain omega-3 fatty acids 3
Dairy Products:
- Milk, yogurt, and cheese are reliable sources of vitamin B12 2, 6
- Dairy products contain lower quantities compared to meat but remain important contributors to B12 intake 4
- Four portions of calcium-rich dairy foods daily are recommended for older adults 3
Eggs:
- Eggs contain vitamin B12, though bioavailability is relatively poor (<9%) compared to other animal products 5, 6
Fortified Foods for Those Avoiding Animal Products
Fortified Breakfast Cereals:
- These are particularly valuable sources for vegans, vegetarians, and elderly individuals 3, 1, 2, 5
- Fortified cereals are key contributors to B vitamin intakes, especially in older age groups 3
Fortified Plant-Based Products:
- Fortified soy milk and other plant milks can help maintain adequate B12 levels 1
- Some dried green and purple seaweeds (nori) contain substantial amounts of B12, though most edible algae contain none or only traces 5
Critical Considerations for Plant-Based Diets
Vitamin B12 is NOT present in foods of plant origin 7, 8
- Strict vegetarians and vegans who consume no animal products (including no milk, eggs, or dairy) require B12-fortified foods or supplements 1, 7, 8
- A vegetarian diet without any animal products does not supply vitamin B12 7
- Most edible blue-green algae (cyanobacteria) predominantly contain pseudovitamin B12, which is inactive in humans and unsuitable as a B12 source 5
Bioavailability and Absorption
Absorption efficiency varies by source:
- Sheep meat: 56-89% bioavailability 5
- Chicken meat: 61-66% bioavailability 5
- Fish meat: 42% bioavailability 5
- Eggs: <9% bioavailability 5
Absorption is limited per meal:
- The intrinsic factor-mediated intestinal absorption system saturates at approximately 1.5-2.0 μg per meal under physiologic conditions 5
- Only about 50% of dietary vitamin B12 is absorbed by healthy adults with normal gastrointestinal function 5
- Small, frequent daily doses are more effective than infrequent large doses 8
Special Population Considerations
Older Adults:
- Food-bound malabsorption affects up to 20% of older adults 2
- Consideration should be given to increasing fortification levels with vitamin B12 to optimize status 3
Pregnant and Lactating Women: