6 Symptoms of Vitamin B12 Deficiency You Should Know

Vitamin B12 is a water-soluble vitamin that is important for human health. This vitamin is important for producing red blood cells and DNA, as well as supporting a healthy nervous system. It is found mostly in animal products, such as fish, meat, poultry, dairy, and eggs. Some plant-based milks or breads may be fortified with B12, and some edible algaes or seaweeds have been found to have active B12, but otherwise, it's difficult to get vitamin B12 from plants.

Having low levels of vitamin B12 is relatively common, especially as we get older. If you are vegan or have trouble absorbing the vitamin from the food you eat, you run a higher risk of deficiency. A person may suffer from vitamin B12 deficiency for years before the symptoms begin to show. Even when they do show, it can be very difficult to diagnose.

Some physicians may even mistake a vitamin B12 deficiency for a folate deficiency. When you are low on vitamin B12, your folate levels may also drop. A doctor may help correct the folate deficiency but still miss the underlying issue of B12 deficiency3. Watch for these 6 signs and symptoms of an actual vitamin B12 deficiency:

1. Pale/Jaundiced Skin

Many people who are B12 deficient may have a slight yellow coloring or a pale appearance. It could be seen in the whites of the eyes or on the skin and it is known as jaundice. This occurs because the low levels of B12 reduce the production of red blood cells.

Without B12, the DNA instructions for building red blood cells are not complete, so the cells don't divide4. This leads to a condition known as megaloblastic anemia, where the red blood cells in your bone marrow are too large to pass into the circulatory system. That reduces the number of red blood cells in the body, and your skin may look pale as a result.

Those blood cells are also fragile and break down quickly, which may produce excessive bilirubin, a brownish red substance that is produced in the liver when old blood cells break down. Too much bilirubin gives your eyes or skin a yellow coloring5.

2. Fatigue and Weakness

Fatigue and weakness are common symptoms of vitamin B12 deficiency and often the first symptoms to show. When you don't have enough B12 to produce red blood cells, your blood has trouble transporting oxygen to the other cells of your body. Since your cells are lacking in oxygen, you may feel weak and tired.

This is sometimes associated with an autoimmune condition in the elderly known as pernicious anemia. Those who have this condition don't produce enough of a protein known as intrinsic factor, which is neccesary for the body to absorb vitamin B12 int he gut. Having enough intrinsic factor can help to prevent a deficiency in vitamin B12.6

3. Pins and Needles

Vitamin B12 produces myelin, a fatty substance that surrounds the nerves and provides protection7. If you don't have enough B12 and myelin is not produced in the proper way, the nervous system experiences problems. You may experience the sensation of pins and needles, known as paresthesia. If you have been B12 deficient for an extended amount of time, nerve damage may occur. 


4. Mobility Changes

B12 deficiency may eventually damage the nervous system and cause changes to how you move and walk. It could have an impact on your coordination and balance, making it more likely for you to fall.

This imbalance is an often underdiagnosed symptom in elderly people who are B12 deficient. Treating and preventing deficiencies in those who are over the age of 60 may help to improve mobility9. It may also be seen in younger people who are severely deficient in B1210.

5. Inflamed Tongue and Mouth Ulcers

B12 deficiency can result in Glossitis, a term that is typically used to describe an inflamed tongue that changes both shape and color. It may appear red, swollen and could be painful. The inflammation may also produce a smooth appearance to the tongue, as the bumps that house the taste buds may stretch out and disappear. Glossitis can also change how you speak and eat. 

Studies have shown that a swollen tongue with long, straight lesions may be one of the first signs of a B12 deficiency11. Other oral symptoms may also appear with a B12 deficiency. These could include a sensation of pins and needles in the tongue, burning and itching sensations in the mouth, and mouth ulcers.

6. Dizziness or Breathlessness

When a B12 deficiency results in anemia, it could leave you short of breath and dizzy. It is a problem that gets worse if you exert yourself. Since your body is lacking sufficient red blood cells, it pulls oxygen from other cells in the body.

It is important to note that these symptoms may occur for many reasons. If you notice that you have a problem with breathlessness, it should be investigated with the help of a physician.

The Bottom Line

Vitamin B12 deficiency is a relatively common issue and can be difficult to identify. If you are at a higher risk for this deficiency, talk to your physician.

A problem with B12 deficiency is often easy to prevent or treat by simply ensuring that you get enough vitamin B12 in your diet, or by taking a B complex or B12 supplement.


1. https://www.ncbi.nlm.nih.gov/pubmed/22116706, Cobalamin deficiency, 2012;56:301-22. doi: 10.1007/978-94-007-2199-9_16

2. https://www.ncbi.nlm.nih.gov/pubmed/23782218/, Biologically active vitamin B12 compounds in foods for preventing deficiency among vegetarians and elderly subjects, 2013 Jul 17;61(28):6769-75. doi: 10.1021/jf401545z. Epub 2013 Jul 2

3. https://www.ncbi.nlm.nih.gov/pubmed/17209196, Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification, 2007 Jan;85(1):193-200

4. https://www.ncbi.nlm.nih.gov/pubmed/16988104, Megaloblastic anemia and other causes of macrocytosis, 2006 Sep;4(3):236-41.

5. https://www.ncbi.nlm.nih.gov/pubmed/1109492, Clinical approach to jaundice, 1975 Jan;57(1):118-24

6. https://www.ncbi.nlm.nih.gov/pubmed/24424200, Diagnosis and classification of pernicious anemia, 2014 Apr-May;13(4-5):565-8. doi: 10.1016/j.autrev.2014.01.042. Epub 2014 Jan 11

7. https://www.ncbi.nlm.nih.gov/pubmed/24248213, Cobalamin deficiency: clinical picture and radiological findings, 2013 Nov 15;5(11):4521-39. doi: 10.3390/nu5114521

8. https://www.ncbi.nlm.nih.gov/pubmed/3374544/, Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis, 1988 Jun 30;318(26):1720-8

9. https://www.ncbi.nlm.nih.gov/pubmed/14695861/, Vitamin B12 and folate deficiency in later life, 2004 Jan;33(1):34-41 10. https://www.ncbi.nlm.nih.gov/pubmed/23536622, Vitamin B12 deficiency presenting as acute ataxia, 2013 Mar 26;2013. pii: bcr2013008840. doi:

10.1136/bcr-2013-008840 11. https://www.ncbi.nlm.nih.gov/pubmed/19231648/, Glossitis with linear lesions: an early sign of vitamin B12 deficiency, 2009 Mar;60(3):498-500. doi: 10.1016/j.jaad.2008.09.011