vitamin b12 deficiency symptoms
October 30, 2019 health No Comments


More people are becoming vegan nowadays. This is a great news, but it can also have consequences. Adults need about 2,4 micrograms of vitamin B12 per day (also known as cobalamin).

Vitamin B12 is mostly found in animal products like meat, fish, chicken and milk. When living on a vegan diet, there are chances that you’re lacking this vitamin, which can create health problems (3).

Vitamin B12 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. Our own body does not produce vitamin B12, therefore we need to get it through our food. Supplements are also a great way to receive enough B12.

But before you do so, please consult a physician if you experience any of the following symptoms.


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 depressed (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).

In short: because of the nausea due to the issues around the digestive track, you can experience a loss of appetite or even weight loss.


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.


To prevent a deficiency in vitamin B12, it’s helpful to take supplements. Especially if you are vegan or vegetarian.

Marine phytoplankton provides you with a stable amount of vitamin B12. These are completely plant-based, making them suitable for vegans and vegetarians.

Our Plant Power Supplements powder 120 and capsules 240, contain 23% of the reference daily intake (RDI) of B12.

How do you recognize an iron, iodine and vitamin B1 deficiency, are also part of the blog series:  Health | Plankton Nutrients


Written by Nannochloropsis