Symptoms Vitamin B12 Deficiency?



Vitamin B12 (also known as cobalamin) is used to create blood cells. When the body doesn’t have enough B12, it will be unable to transport enough oxygen throughout the body. When this occurs, the body will show symptoms of a B12 deficiency. These symptoms are not only physical, but also sometimes mental.

Vitamin B12 is a important vitamin to the human body. Since our body is unable to create this vitamin itself, we need to get Vitamin B12 from our foods. Vitamin B12 is mostly found in animal products (excluding phytoplankton) like meat, chicken, milk, fish.

When living on a vegan diet, there are chances that you’re lacking this vitamin, which can create health problems (3). There are certain groups of people that have a higher risk of creating a B12 deficiency. Those people may benefit from using vitamin B12 supplements next to their daily meals.

It is, however, important to note that if you suspect you have a shortage of cobalamin, you should always consult a doctor before taking any supplements.

People with a higher risk of obtaining an vitamin B12 deficiency are:

  • Those following a vegetarian or vegan diet,
  • Patients with a small bowel disease (such as Crohn's disease),
  • Those who abuse alcohol and / or laughing gas.
  • People with a stomach disorder (stomach operation or gastric bypass),
  • Seniors.

A shortage of vitamin B12 can be recognized by the following symptoms. If you experience one or more of these symptoms, it may be wise to consult a physician.


Vitamin B12 is needed for DNA synthesis. The DNA-sequences in the organs which have a greater cell turnover rate (meaning they grow much faster) will be affected by this. Bone marrow is one of them.

A too high deficiency in vitamin B12 can cause deformities in the bone marrow, making it harder to move (9)(10).

In short: a deficiency of vitamin B12 stops DNA synthesis and causes the bone marrow to deform.


A theory about vitamin B12 says that B12 helps to break down a chemical in the brain called homocysteine. This chemical is responsible for a lesser mental health.

A lack in vitamin B12 can cause someone’s mood to be influences by this chemical, resulting in them getting irritated more often or even becoming depresse (1).

In short: vitamin B12 helps to break down a chemical responsible for a bad mental health. A shortage of B12 causes a person to become more irritable or depressed.


Red blood cells help to give the body its natural colour. A lack of blood cells due to a vitamin B12 deficiency can turn the body pale. It can also turn the body yellow. This is called jaundice. When the blood cells are weakened, they get broken down more easily by the liver.

This then creates a waste product called bilirubin, which turns the skin yellow-ish. It’s one of the main characteristics of jaundice. It’s also commonly associated with anaemia (4).

In short: a lack of red blood cells can turn the body pale or yellow due to the build-up of bilirubin.


A study has linked a deficiency of vitamin B12 to Alzheimer’s (5).

More studies connect a lack of vitamin B12 to problems with thinking and memorizing. This is caused by the lack of red blood cells in the body. They transport oxygen to the brain. When there aren’t enough blood cells to transport this oxygen, there is not enough to be transported to the brain as well.

In short: a deficiency in vitamin B12 has been associated with memory and thinking problems due to the lack of oxygen being transported towards the brain.


Vitamin B12 helps in the production of a protein called myelin. This substance protects our nerves, all around, by this greasy insulation layer. When there is not enough B12 in the body, there won’t be enough myelin produced to protect these nerves.

In the long term, these nerves can become damaged. Damaged nerves, especially peripheral nerves will respond with a tingling sensation in both hands and feet (6)(7).

In short: a shortage of vitamin B12 will reduce the amount of myelin produced, which stops the protection of the nervous system. This can result in tingling sensations in the hands and feet.


]When the body is short of vitamin B12, this can cause the nerve ends to become damaged. This happens because the production of myelin is halted. Long-term damage will eventually also reach the nerves of the eyes. It obstructs the nervous signal that travels from your eye to your brain.

This can lead to blurred or missing visual. This condition is called optic neuropathy (11).

In short: a lack of vitamin B12 can damage the optic nerves, causing you to get blurred vision.


The digestive tract is an important system in the body. When a lack of oxygen occurs due to a lack of vitamin B12, it will affect the digestive system. It will have troubles functioning and processing foods and minerals.

This can cause nausea, diarrhoea or even vomiting (4)(9).

In short: a lack of oxygen due to a B12 deficiency will affect the digestive track, resulting in nausea, diarrhoea and even sometimes vomiting.


When there are less red blood cells produced, there will be less oxygen to transport towards the mouth. When someone has a B12 deficiency and because of that a lack of red blood cells, it will affect the health of their mouth.

Symptoms include a burning sensation, mouth ulcers and even a swollen tongue (9).

In short: a B12 deficiency can cause the tongue to swell and the mouth to experience a burning sensation and ulcers due to a lack of oxygen being transported to the mouth.


Because a lack of vitamin B12 can cause problems with the digestive track, a person may experience loss of appetite due to nausea or vomiting.

When this person also experiences excessive diarrhoea, this can lead to weight loss (4).

Kortom: vanwege de misselijkheid als gevolg van de problemen rond het spijsverteringskanaal, kan je een verlies van eetlust of zelfs gewichtsverlies ervaren.


A lack of vitamin B12 has been proven to affect the myelin production, which protects the nerves. Short term nerve damage will lead to a tingling sensation in hands and feet, like we discussed before.

However, a long-term damage to the nerves will result in problems with walking and moving. Eventually this may lead to loss of muscle mass as well (6)(7).

In short: a lack of vitamin B12 can cause movement problems in the long term. Even resulting in the loss of muscle mass.

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