Vitamin B12 Deficiency: Signs, Causes and Food Sources
Vitamin B12 helps make red blood cells and keeps nerves healthy, and a shortage can cause tiredness, tingling in the hands and feet, and memory or mood changes. It is found mainly in animal foods, so vegetarians, vegans and older adults, and people with certain stomach conditions or medicines, are more likely to run low.
What Does Vitamin B12 Do?
Vitamin B12 is needed to make red blood cells, build DNA and keep the nerves working. Without enough, the body can develop a type of anaemia and nerve problems. The body stores B12 in the liver for years, so deficiency often develops slowly.
Common Signs of Low B12
Tiredness has many causes, including low vitamin D and an underactive thyroid; see vitamin D deficiency signs and causes and why hypothyroidism causes fatigue.
Who Is More at Risk?
- People who follow a vegan diet or eat little meat, fish, eggs or dairy
- Older adults, who absorb B12 less well
- Pernicious anaemia, Crohn’s disease or coeliac disease
- Weight-loss or stomach surgery
- Long-term use of metformin or acid-reducing medicines
Food Sources of B12
Testing and Treatment
A simple blood test shows your B12 level, and your doctor may check for related causes. Treatment depends on the cause and may be B12 tablets or injections. Do not start high-dose supplements without advice, because symptoms like tingling can also come from other conditions that need different treatment.
- You have numbness, tingling or trouble walking or balancing
- You have memory problems or confusion
- You are very tired, breathless or look pale
Have questions about supplements?
Talk to a pharmacist before starting any vitamin or medicine.
Contact usFrequently Asked Questions
Can vegans get enough B12?
Only from fortified foods or supplements, so vegans are advised to use them regularly.
Can you take too much B12?
B12 has a low risk of toxicity, but you should still follow your doctor’s advice on dose and form.
How long does recovery take?
Energy often improves within weeks, but nerve symptoms can take months and may not fully recover if treatment is delayed.
More Reading
Sources: U.S. National Institutes of Health, Office of Dietary Supplements, “Vitamin B12 Fact Sheet for Health Professionals”; NHS guidance on vitamin B12 deficiency; Mayo Clinic patient information.