Vitamin B12 plays a vital role in a variety of reactions around your body. It is involved in the formation of red blood cells, DNA, and the normal function of the nervous system. Deficiency in Vitamin B12 can result in anaemia and nerve damage.
Potential signs of low Vitamin B12
Feeling weak and fatigued: Vitamin B12 is vital for making healthy red blood cells which carry oxygen around your body. Low levels of Vitamin B12 can reduce the oxygen being transported to your body’s cells, making you feel tired and weak.1
Feeling dizzy and out of breath: Anaemia caused by Vitamin B12 deficiency can result in feeling dizzy and out of breath. This happens as the red blood cells are not able to transport enough oxygen to your body’s cells.1
Mouth ulcers and sore tongue: A sore, red or swollen tongue can be an early sign of Vitamin B12 deficiency.2 The inflammation of the tongue makes it look smooth and can change the way you speak and eat. This condition is known as ‘Glossitis’. Mouth ulcers may also occur with Vitamin B12 deficiency.
Pale or yellow tinge to the skin and white of the eyes: Vitamin B12 deficiency can lead to a type of anaemia called ‘megaloblastic anaemia’, in which the red blood cells are large and fragile.
The fragile red blood cells break down causing an excess of bilirubin, a slightly brown or red coloured substance that is produced by the liver when old red blood cells are broken down. This is what gives the skin and whites of the eyes a yellow tinge.3
Pins and needles: Vitamin B12 is needed to produce myelin, a substance that forms a protective layer around your nerves. Low Vitamin B12 can lead to damage to this protective layer and cause nerves to stop functioning properly. Pain, numbness or a prickling sensation in your hands and feet, like pins and needles, may occur when your Vitamin B12 levels are low.1
If a Vitamin B12 deficiency is left untreated, damage to the nervous system could affect your balance and coordination, which can impact the way you walk and move.4
Who might be at risk of low Vitamin B12?
Deficiency of Vitamin B12 usually occurs due to problems with how your body absorbs it. Vitamin B12 has to be combined with a protein in your stomach called ‘intrinsic factor’ before your body can absorb it. Pernicious (harmful) anaemia can occur when you have a lack of ‘intrinsic factor’ and is a condition most commonly found among middle-aged and older adults.
Vitamin B12 deficiency due to inadequate dietary intake is less common, although it is much more common among plant-based and vegan diets. If your diet contains some animal products (e.g. meat, fish, dairy, eggs), then the small requirement for the vitamin will be met.
However if your diet is vegan or plant-based and you’re not eating animal foods, or fortified foods, you may not be getting enough Vitamin B12. Vitamin B12 fortified foods include yeast extract, such as Marmite or yeast flakes, some plant milk alternative drinks, soya yoghurts and breakfast cereals.
by Dr Laura Wyness, PhD, RNutr
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1. NHS (2020) Symptoms Vitamin B12 or folate deficiency anaemia. Available: https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/symptoms/
2. Graells et al (2009) Glossitis with linear lesions: an early sign of vitamin B12 deficiency. Available: https://doi.org/10.1016/j.jaad.2008.09.011
3. Dusol & Schiff (1975) Clinical approach to jaundice. Available: 1080/00325481.1975.11713948
4. Miles et al (2015) Is there an association of vitamin B12 status with neurological function in older people? A systematic review. Available: 1017/S0007114515002226
5. The Vegan Society (2020) Sources of Vitamin B12. Available: https://www.vegansociety.com/resources/nutrition-and-health/nutrients/vitamin-b12