Vitamin B12 is a crucial B vitamin. It is needed for nerve tissue health, brain function and the production of red blood cells. Vitamin B12 deficiency occurs when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly. Vitamin B12 deficiency symptoms can develop if a person lacks the vitamin in their diet. Having a deficiency to the vitamin could lead to irreversible neurological symptoms.
Vitamin B12 is naturally found in animal foods, including meats, fish, poultry, eggs and dairy.
It can also be found in products which are fortified with B12 which include some varieties of bread and plant-based milk.
Having a deficiency to the vitamin is unfortunately quite common, especially in the elderly, vegans and vegetarians.
A person is at risk of developing a deficiency if they don’t get enough from their diet or aren’t able to absorb enough from the food you eat.
READ MORE: Vitamin B12 deficiency symptoms: Look out for this sign when you go to the toilet
One of the main symptoms of having a vitamin B12 deficiency is experiencing blurred or disturbed vision.
This can occur when an untreated B12 deficiency results in nervous system damage to the optic nerve that leads to the eyes.
The damage can disrupt the nervous signal that travels for the eye to the brain, impairing one’s vision.
In a study with the US National Library of Medicine National Institutes of Health, B12 deficiency was analysed.
The study noted that a deficiency to vitamin B12 doubled alter the neurological manifestations in the absence of anaemia.
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Eye twitch
An eye twitch could be a sign of vitamin B12 deficiency, according to Thyroid Patient Advocacy.
This usually occurs in one eye or the other and can appear even in “borderline” vitamin B12 deficiency.
It advises: “It can occur on the eyelid or just below the eye.
“This is not usually painful, just annoying.”
The twitch can occur in one eye or the other.
Jaundice
If a person has a vitamin B12 deficiency they could develop jaundice, according to Bupa.
This makes a person look pale or have a yellow tinge. In terms of the eyes, they may appear to have a yellowish colour to them and look a lot less white.
Jaundice is caused due to the fragility of red blood cell production which thens breaks down and causes an excess of bilirubin.
Bilirubin is produced by the liver when it breaks down old blood cells and is slightly red or brown colour.
Having large amounts of bilirubin gives the eyes a yellow colour.
Most cases of vitamin B12 deficiencies can be easily treated with either injections or tablets which help to replace the missing vitamins in the body.
The NHS said: “Vitamin B12 supplements are usually given by injection first. Then, depending on whether your B12 deficiency is related to your diet, you’ll either require B12 tablets between meals or regular injections.
“These treatments may be needed for the rest of your life.” In some cases, improving one’s diet can help treat the condition.
“Eating more foods such as meat, eggs, yeast extracts found in Marmite and specially fortified foods could help treat the deficiency.