General symptoms of B12 deficiency
- A pale yellow tinge to your skin
- A sore and red tongue (glossitis)
- Mouth ulcers
- Pins and needles (paraesthesia)
- Changes in the way that you walk and move around
- Disturbed vision
- Changes in the way you think, feel and behave.
- A decline in your mental abilities, such as memory, understanding and judgement (dementia)
These conditions can often be diagnosed based on your symptoms and the results of a blood test.
People following a strict vegan or vegetarian diet are far more likely to become deficient in B12.
Vitamin B12 is found naturally in a wide variety of animal foods and is added to some fortified foods.
As the NIH explains, plant foods have no Vitamin B12 unless they are fortified.
There are vegan and vegetarian-friendly sources of B12, however, such as yeast extract (including Marmite), as well as some fortified breakfast cereals and soy products, adds the NHS.