Vitamin B12, or cobalamin, is important for the processing of carbohydrates, proteins and fats into glucose that can be utilized by the body. Vitamin B12 is naturally found only in animal foods such as milk, dairy products, eggs, meat, fish and shellfish. Strict vegetarians are more likely to experience low levels of B12. Older patients may also have low B12 levels due to decreased absorption of B12. Low B12 levels may cause several symptoms.
Hematologic
Vitamin B12 works together with folic acid to make red blood cells. Patients with low B12 levels experience a form of anemia called megaloblastic anemia. In megaloblastic anemia, the bone produces immature red blood cells that are larger than normal red blood cells. These abnormal red blood cells are not able to store hemoglobin, which results in low oxygen levels in the blood. Symptoms of megaloblastic anemia include fatigue, pale skin, palpitations, feeling weak, shortness of breath and chest pain.
Neurologic
Vitamin B12 is necessary for maintaining healthy nerve cells. Patients with low B12 levels may experience symptoms such as tingling and numbness in the hands and feet, changes in ability to walk, memory problems, depression, sadness, personality changes, psychosis, irritability and dementia, according to the Centers for Diseases Control and Prevention. Untreated B12 levels may lead to permanent nerve damage.
Cardiovascular
Vitamin B12 together with vitamin B6 and folic acid are important for lowering levels of the amino acid homocysteine, according to the American Family Physician website. Homocysteine is an amino acid produced during digestion of food. Low levels of homocysteine lead to decreased risks for myocardial infarction and stroke. Patients with high levels of homocysteine are more likely to experience cardiovascular events such as heart attack and stroke.
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