Vitamin B12 Deficiency Symptoms and Recommended B12 Intake

Vitamin B 12, also known as cobalamin, helps make DNA, blood cells and is also crucial for a healthy brain and immune system. It is mainly found in animal products like eggs, meat, shellfish and dairy products. Vegetarians are more likely to be deficient in this vitamin. When you grow older, your ability to absorb this vitamin also decreases and this too can cause vitamin B12 deficiency.

People at higher risk of B12 Deficiency

Though most people can get this vitamin from their diet, some people are at a higher risk of developing vitamin B12 deficiencies. These groups of people include:

  • People above the age of 50
  • People who have undergone surgery to remove a part of their bowel
  • Individuals who mainly eat vegetarian food
  • People with atrophic gastritis, a condition where your stomach lining becomes thin
  • People suffering from pernicious anemia find it difficult to absorb vitamin B12
  • Individuals with medical problems related to small intestines like Crohn’s disease, celiac disease, bacterial grown or a parasite
  • People with immune system disorders like Grave’s disorder or lupus
  • People who take metformin for diabetes
  • Individuals who have been taking antacid drugs over an extended period

Suggested Read Vitamin-D Deficiency Symptoms

Vitamin B12 Deficiency Symptoms

Symptoms of vitamin B12 deficiency can take a long time to show up and can sometimes be mistaken for folate deficiency. These are the signs and symptoms of vitamin B12 deficiency:

1. Fatigue

Fatigue is one of the most common signs of vitamin B12 deficiency. Our body depends on this vitamin to make red blood cells, which supply oxygen to the organs. Without an adequate supply of oxygen, you are bound to feel tired.

Pernicious anemia, an autoimmune condition, can cause this kind of anemia in the elderly. People suffering from pernicious anemia (1) do not produce enough intrinsic factor, which is essential for preventing vitamin B12 deficiency.

This intrinsic factor is an important protein which is responsible for binding vitamin 12 in our gut so that we can absorb it.

2. Pins and needles sensation

These pins and needles feeling in the body is a result of the nerve damage caused by the lack of oxygen in the cells. Vitamin B12 plays an essential role in the metabolic pathway that produces myelin.

Myelin is a fatty material, and it covers and protects our nerves. Without myelin, our nerves can get damaged, and this can lead to paresthesia (2).

3. Jaundiced skin

If your skin is looking pale and yellow, vitamin B12 deficiency may be the culprit. When there is a cobalamin deficiency, the red blood cells become very fragile, and they break easily.

This loss of red blood cells leads to a release of the bilirubin pigment that makes your skin yellow. This type of anemia is known as megaloblastic anemia (3).

4. Lesser balance and coordination

People with cobalamin deficiency often feel wobbly. This loss of balance happens when this deficiency is left untreated for a long time.

This deficiency damages the nervous system and affects your balance and coordination. People above the age of 60 are prone to these symptoms. It is essential to prevent and treat this deficiency in the elderly to improve mobility and coordination (4).

5. Memory loss

Short-term memory loss and cognitive decline are also the signs of vitamin B12 deficiency (5). Sometimes this forgetfulness can be misdiagnosed as dementia or Alzheimer’s in the elderly.

Thankfully once it is correctly identified as a deficiency by the blood test and you start taking supplements, the symptoms of forgetfulness will begin to disappear.

Vitamin B12 Deficiency Symptoms info graphic

6. Mood changes

Low level of cobalamin is the body has also been linked to mood changes, depression, and even dementia. Low levels of vitamin B12 in the body can lead to an increase in the homocysteine levels in the body.

This increase in homocysteine levels can cause damage to the brain tissue, which further leads to interference in the signals of the brain and this leads to mood changes (6).

Though regular intake of supplements can improve the symptoms of depression, however medical therapy is as important.

7. Blurred vision

Vitamin B12 deficiency can result in damage to the optic nerve. The damage can disrupt the nerve signals between the eye and the brain and can cause this condition known as optic neuropathy.

If you have blurred or double vision, you must get your vitamin B12 levels checked. This condition is treatable and reversible with supplements (7).

8. Breathlessness

People with vitamin B12 deficiency can suffer from shortness of breath and dizziness when they exert themselves. You may also feel dizzy if you get up from a sitting position too fast or if you are going up the stairs.

This breathlessness and dizziness are because your red blood cells can not get enough oxygen to your body cells.

9. Glossitis

Glossitis is a condition in which your tongue changes shape and color and becomes red and swollen. The papillae or those tiny bumps on the tongue disappear, making the tongue look smooth.

Since most of these papillae contain taste buds, you may also lose your sense of taste. In some cases, this loss of taste can make you lose weight.

Burning and itching on the tongue and mouth ulcers are also some common signs of vitamin B12 deficiency (8).

10. High fever

In some rare cases, vitamin B12 deficiency can also lead to high temperature (also known as pyrexia).

Though it is not very clear why this happens, this fever disappears once you treat the patient with supplements of vitamin B12 (9).


However, you must note that not all fevers are linked to vitamin B12 deficiency.

Recommended daily intake of B12

The recommended daily intake varies according to age. Here is the recommended daily dose of vitamin B12 in Micrograms (mcg):


  • 0 to 6 months: .4 mcg
  • 7 to 12 months: .5 mcg


  • 1 year to 3 years: .9 mcg
  • 4 years to 8 years: 1.2 mcg
  • 9 years to 13 years: 1.8 mcg
  • 14 years to 18 years: 2.4 mcg


  • 2.4 mcg
  • Pregnant women: 2.6 mcg
  • Breastfeeding women: 2.8 mcg


You can prevent vitamin B12 deficiency by including meat, fish, eggs and dairy products in your diet. If your body cannot absorb this vitamin naturally due to some medical condition, your doctor will prescribe supplements for you.


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