Vitamin

Vitamin B12

Vitamin B12 helps make red blood cells and keeps the nervous system healthy. It is found mainly in animal foods, so vegans and some others can become deficient, causing tiredness and anaemia.

Written by Meds Global Health Clinical Team · Clinically reviewed by Dr Muhammad Suffyan, MB BS, Founder & Clinical Director · Last reviewed · How we review

What it is

Vitamin B12 is a water-soluble vitamin essential for blood and nerve health, obtained mainly from animal-based foods.

What it does

It helps make red blood cells, keeps nerves healthy, and supports the release of energy from food and the making of DNA.

Good sources

Meat, fish, eggs, milk and dairy, and fortified foods such as some plant milks, yeast extract and breakfast cereals.

Deficiency and who is at risk

Because it comes mainly from animal foods, vegans and vegetarians can be at risk, as can older adults and people with certain gut conditions that reduce absorption (such as pernicious anaemia). Deficiency causes tiredness, a particular anaemia, and sometimes nerve symptoms like tingling.

Balance

Can you have too much?

B12 from food and normal supplements is not associated with harm, as excess is generally removed by the body.

Education and reference only. This is general nutrition information, not personal advice, and does not give doses. Ask a pharmacist, GP or registered dietitian before starting supplements, especially with a health condition or in pregnancy.

Answers

Vitamin B12: frequently asked questions

Who is at risk of vitamin B12 deficiency?

Vegans and vegetarians (as it comes mainly from animal foods), older adults, and people with conditions affecting absorption such as pernicious anaemia or after some gut surgery.

What are the symptoms of low B12?

Tiredness, breathlessness, a sore tongue, and sometimes tingling or numbness. A blood test can check your level, and treatment (tablets or injections) depends on the cause.

Related

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Sources

Where this is drawn from

  • NHS — Vitamins and minerals
  • British Dietetic Association (BDA)
  • UK Scientific Advisory Committee on Nutrition (SACN)

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