Vitamin B12 deficiency is caused by pernicious anemia. Pernicious anemia is caused by a lack of glycoprotein called intrinsic factor. Without the glycoprotein, which is required for absorption of vitamin B12, a deficiency occurs. When intrinsic factor is secreted by the stomach it binds with B12 and is transported to the small intestine for absorption. When the absorption is unable to occur, a B12 deficiency is the result. Vitamin B12 is required for the conversion of homocysteine to methionine, which is one of the essential amino acids that is required to synthesize proteins.

When vitamin B12 is deficient or impaired cell division is slowed. When this slow division occurs, red blood cells are enlarged and are more likely to be destroyed by the immune system. Vitamin B12 deficiency causes many symptoms, which include gastrointestinal problems as well as neurological problems. The following is a list of common symptoms caused by vitamin B12 deficiency.

There are some symptoms of B12 deficiency that can be similar to other disorders or problems and in many causes seem mild. These symptoms include:

1. Incontinence

Incontinence is the inability of the bladder to hold urine and leakage occurs.

2. Chronic Fatigue

Chronic fatigue is caused by Vitamin B12 deficiency and is a persistent feeling of tiredness and weakness in the body.

3. Weight Loss

Weight loss occurs when the body does not have adequate amounts of B12. When excessive weight loss occurs many other problems can arise including sleeplessness, weakness and gastrointestial problems.

4. Shortness of Breath

When the body has a B12 deficiency, often shortness of breath is a symptom that occurs. Labored breathing results because the B12 is not being absorbed properly.

5. Tingling in Fingers and Toes

Tingling in the fingers and toes is caused by either poor circulation or a neurological problem. With adequate B12, this symptom can be treated.

6. Forgetfulness and Confusion

When the neurological system is deprived of B12, forgetfulness and confusion is often a result.

7. Psychosis and Hallucinations

Psychosis and both audio and visual hallucinations can occur at the advanced stages of a vitamin B12 deficiency.

8. Tremors

Uncontrolled movements of the extremities results in prolonged deficiency of B12 in the body.

9. Depression

Depression is also a symptom that occurs after the body has been deprived for a long period of time. The mental state of a person can be altered without adequate nutrition.

The neurological symptoms often happen after a prolonged vitamin B12 deficiency and can be confused with other disease such as Gullian-Barre Syndrome, Multiple Sclerosis, Alzheimer's, Parkinson's Disease and Amyotrophic lateral sclerosis (ALS). There are several tests that can be performed to diagnose a B12 deficiency and in turn rule out any other health problems. It is important to eat foods rich in B12 or to incorporate supplements of B12 into daily life to avoid health problems.