💊 Nutrition
Vitamin B12 Foods — Complete List and Who Needs to Supplement (2026)
The best food sources of vitamin B12 ranked by content, daily requirements, deficiency symptoms, and who should supplement. Updated January 2026.
Key Takeaways
- B12 is only found naturally in animal products — vegans and vegetarians must supplement
- Clams and oysters contain vastly more B12 than any other food
- 1 in 6 UK adults over 60 are B12 deficient — absorption decreases with age
- Untreated B12 deficiency causes irreversible nerve damage
- UK RDA is 1.5 mcg/day — one tin of sardines provides more than 400%
Why Vitamin B12 Is Critical
Vitamin B12 is essential for red blood cell formation, neurological function (myelin sheath maintenance), DNA synthesis, and cellular energy metabolism. Unlike most nutrients, it is found almost exclusively in animal-derived foods. Deficiency causes megaloblastic anaemia, peripheral neuropathy, cognitive decline, and depression — and the neurological damage can be irreversible if prolonged.
1.5 mcg
UK daily RDA — easily met with animal foods
1 in 6
UK adults over 60 have B12 deficiency
0
Natural B12 in plant foods — vegans must supplement
Best Food Sources Ranked
| Food | B12 per 100g | % UK RDA per typical serving |
|---|---|---|
| Clams (cooked) | 98.9 mcg | 6,600% per 100g |
| Beef liver | 70.7 mcg | 4,700% per 100g |
| Oysters | 16.0 mcg | 1,070% per 100g |
| Sardines (canned) | 8.9 mcg | 593% per 100g tin |
| Salmon (150g cooked) | 3.2 mcg | 213% per serving |
| Tuna (canned, 185g) | 2.5 mcg | 167% per tin |
| Beef (100g cooked) | 2.6 mcg | 173% per serving |
| Eggs (2 large) | 0.9 mcg | 60% per 2 eggs |
| Milk (200ml) | 0.5 mcg | 33% per glass |
| Fortified plant milk (200ml) | ~0.75 mcg | ~50% per glass |
Deficiency Symptoms
- Persistent fatigue and weakness
- Pins and needles in hands and feet
- Pale or yellowish skin
- Mouth ulcers and inflamed tongue (glossitis)
- Memory problems and cognitive difficulties
- Mood changes — depression, irritability
- Unsteady gait in advanced deficiency
Who Must Supplement
- Strict vegans and vegetarians — no natural plant B12 sources
- Adults over 50 — reduced stomach acid impairs B12 absorption from food
- Long-term metformin users — metformin depletes B12 over years (30% of users)
- People with pernicious anaemia — autoimmune condition blocking B12 absorption
- Those who have had gastric surgery
Frequently Asked Questions
How do I know if I am B12 deficient?▼
Blood test for serum B12 and MMA (methylmalonic acid — more sensitive marker) from your GP. Symptoms: fatigue, tingling hands/feet, mouth ulcers, pale skin, cognitive difficulties. Note: serum B12 can appear 'normal' while tissue deficiency exists — MMA is a better functional marker.
How much B12 should vegans take?▼
2,000 mcg cyanocobalamin weekly OR 250 mcg daily — both are effective standard recommendations. Methylcobalamin at the same dose is an alternative. Take with food for best absorption. Annual blood test to confirm adequate levels.
Does cooking destroy B12?▼
B12 is relatively heat-stable — typical cooking destroys only 20–30%. For maximum retention, prefer shorter cooking times. Canned fish retains essentially all B12 and is one of the most economical high-B12 foods available.
Related Health Guides
Article
B12 Deficiency — Full Guide
Article
Iron Deficiency Symptoms
Calculator
TDEE Calculator
Article
High Protein Foods List
⚕️ Medical Disclaimer: For informational purposes only. Not a substitute for professional medical advice.
Dr
Dr. Emma Clarke, PhD, RD
WellCalc Medical Contributor
All articles reviewed by qualified healthcare professionals following NHS, AHA, and WHO guidelines.