How to Know if You Have a Vitamin B12 deficiency

Vitamin B12 plays an important role for our health and we shouldn’t ignore the signals our body sends us when we have a lack of it
How to Know if You Have a Vitamin B12 deficiency

Written by Okairy Zuñiga

Last update: 26 May, 2022

Vitamin B12 is one of the most important vitamins for the body. Proper levels of the vitamin in the body help to maintain a good metabolism, as well as to improve cellular function and mood.

If you had a vitamin B12 deficiency for more than five years, the consequences can be quite serious.

This is because the role played by this vitamin is so fundamental to certain processes in the body that some call it the “energy vitamin”.

We usually get vitamin B12 through food. However, there are occasions when it might be necessary to take an extra dose at least twice a year to maintain an optimal level.

This vitamin is important because:

  • It’s essential to the production of DNA,
  • It helps maintain healthy nerve cells, blood cells, and all genetic material in the body.

Vitamin B12 doesn’t leave the body in our urine. Actually, our liver, kidneys and other organs store it. Then, we use it from there.

Symptoms of a Vitamin B12 deficiency

Vitamin B12

A vitamin B12 deficiency has many different symptoms, so it’s likely that we don’t all recognise it.

There are studies that link the lack of vitamin B12 with the development of Alzheimer’s disease. As well as this, memory problems, lack of concentration, confusion, and permanent forgetfulness can occur.

One of the determining factors of the onset of degenerative diseases is the reduction of brain mass. The good news is that if you regulate your consumption of vitamin B12, you can reverse the effects  in a short time if they are not too advanced.

80% of detected cases of vitamin B12 deficiency have three conditions in common:

  • Older age
  • Drink more than 6 cups of coffee daily
  • Vegan food

Tingling and fatigue

Another symptom that may indicate a lack of vitamin B12 is the sensation of tingling in the arms and legs that comes from bad blood circulation.

It may be due to other factors. However, it’s always worth checking that your intake of vitamin B12 is adequate.

Sometimes, we can show daily signs of fatigue, discouragement, a feeling of apathy, lack of motivation, or mood swings. Depression is one cause of all of these symptoms, but it’s not the only one.

Although it is not a bad idea to see if you need the help of a psychologist, try to increase your levels of vitamin B12. It may be the immediate solution.

Check that your intake of vitamin B12 is adequate

Digestive problems

Occasionally, people with a vitamin B12 deficiency may experience constipation or diarrhea, depending on general health of each individual.

An onset of dizziness that can even result in fainting may also be indicative of this problem. You should pay special attention if any occasional dizziness lasts for a while.

Although anemia may also cause iron deficiency, it can worsen if there is also a deficiency of vitamin B12. This can lead to a decrease in red blood cells which triggers anemia and other blood problems.

Other symptoms include a lack of appetite, diarrhea, or finding that you have serious problems in performing daily activities.

A lower appetite and slower reflexes

Amongt other, less obvious symptoms, such as possible changes in skin colour (first pale then yellow), are slower reflexes. This comes from a decrease in the activity of the nervous system.

A lack of vitamin B12 is also likely to suppress your appetite. Thus, it’s important to be careful, because it’s not just about eating, but about nourishment. Remember, if you stop eating you might develop problems related to anaemia.


Have you always been quite a relaxed person but now suddenly you are prone to uncontrollable nervousness? This is a possible consequence of a lack of vitamin B12.

Also, people affected by this can become disorientated and lose their spatial awareness. Episodes occur discreetly at first but can become more and more regularly.

Chest pain

A very obvious symptom is chest pain. A lack of vitamin B12 causes deficiencies in the muscles surrounding the sternum.

This triggers sternochondritis that causes acute pain as a result of deficiency in the joints of the chest.

Other possible symptoms

In addition to the above, you may also:

  • Feel cold and a constant numbness unless there really is a change in temperature. This may be accompanied by numbness in the hands and feet.
  • Suffer from episodes of diarrhoea. They may start to appear gradually. In serious cases, they may be accompanied by severely painful bowel movements.
  • Fertility problems. As vitamin B12 has a direct relationship with genetic information, its deficiency may increase the risk of spontaneous abortions, decreased sperm count, and problems with the female reproductive tract.
  • Feel pain in your mouth. You shouldn’t ignore the presence of constant infections or regular bleeding due to the build-up of bacteria. Remember that if you aren’t careful, you can lose your teeth.

Medications that can cause a vitamin B12 deficiency

  • Contraceptives
  • Cancer medications
  • Medication for gout, Parkinson’s disease, and tuberculosis
  • Anti-epileptic medication
  • Potassium supplements
  • Anti-hypertensive drugs
  • Treatments to reduce cholesterol
  • Treatments for psychotic illnesses

The importance of monitoring your vitamin B12 levels

The importance of monitoring your vitamin B12 levels

It’s quite probable that, knowing that certain drugs cause this deficiency, you’re scared and want to stop taking them.

Instead, check with your doctor to rule out the problem and increase your consumption of:

  • Liver and beef
  • Clams
  • Poultry
  • Eggs
  • Cereals

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Oh, R. C., & Brown, D. L. (2003). Vitamin B12 deficiency. American Family Physician.
  • O’Leary, F., & Samman, S. (2010). Vitamin B12 in health and disease. Nutrients.
  • Pawlak, R., Parrott, S. J., Raj, S., Cullum-Dugan, D., & Lucus, D. (2013). How prevalent is vitamin B12 deficiency among vegetarians? Nutrition Reviews.
  • Malouf, R., & Evans, J. G. (2008). Folic acid with or without vitamin B12 for the prevention and treatment of healthy elderly and demented people. Cochrane Database of Systematic Reviews.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.