Vitamin B12 deficiency occurs when the blood levels of vitamin B 12 drop below normal. Vitamin B 12 is essential for the development of red blood cells (RBC), and is also important for the appropriate functioning of nerve tissues.
Deficiency of vitamin B12 significantly affects the functioning of the nerves associated neurological functioning. The following are the signs and symptoms of vitamin B12 deficiency:
In more advanced stages, when the deficiency continues for a prolonged duration, then the nervous system can get affected, and would showcase the following symptoms :
A preliminary physical examination will be done, to study for the signs of vitamin B12 deficiency. In addition, the following tests would also be carried out to diagnose the condition :
Supplementation of vitamin B12, either orally or intravenously, is employed for correcting its deficiency. The vitamin supplement is available either as a single component, or in combination with other nutrients. Complete repletion of liver stores with vitamin B12 requires about 20 injections, along with injections given on monthly basis for maintenance of the stores .
Vitamin B12 injections are either given through the subcutaneous route, or intramuscularly. These injections contain hydroxycobalamin, cyanocobalamin or methycobalamin. Administration of vitamin B12 through the parenteral route, has been shown to enhance the absorption of this vitamin .
Hypokalemia is a common occurrence in patients, who are given supplements of vitamin B12. This is so because potassium is excessively used by the new hematopoietic cells for the process of growth and division.
Individuals with vitamin B12 deficiency have a good prognosis, if the treatment is initiated within 6 months of experiencing the symptoms. Failure to do so can cause permanent damage to the nerves, and other associated problems.
The following are the various factors responsible for causing vitamin B12 deficiency:
The exact prevalence of vitamin B12 deficiency is unknown. However, it has been estimated that about 300,000 – 3 million individuals can get affected by its deficiency. It was also reported that about, 3 to 16% of the population had a vitamin B12 level less than 200 pg/mL (using the cut offs of radioassay techniques). Using cut off value of 300 pb/mL for elderly population, vitamin B12 deficiency was found in 21% of population. In European countries, vitamin B12 deficiency is found in approximately 1.6 to 10% individuals .
After ingestion of foods containing vitamin B12, the low pH of the stomach cleaves cobalamine from dietary protein. This then binds to gastric R binder, and reaches the duodenum and jejunum, where the enzymes present in pancreas digest the complex, and release cobalamin. Following this event, free cobalamin binds with the gastric intrinsic factor (IF). The secretion of IF is dependent on secretion with hydrochloric acid. Therefore, during conditions of achlorhydria, when the secretion of IF is reduced, lead to deficiency of vitamin B12  .
Vegans and vegetarians, who do not consume eggs, are at an increased risk for developing vitamin B12 deficiency. Such individuals should consider consuming several breakfast cereals, which are fortified with vitamin B12. In addition, certain types of soy milk are also fortified with the vitamin, which if consumed, can help maintain the blood levels of vitamin B12. Individuals can also consider popping in multivitamin, which contain about 6 micrograms of vitamin B12, which is sufficient to cover an individual’s daily requirement.
Deficiency of this vitamin, can therefore lead to anemia, and can also cause serious damage to the nerve and brain functioning. Vitamin B12 deficiency occurs at all age groups, and often goes undiagnosed due to its complex etiology. According to the research conducted by the Framingham Offspring Study, it was postulated that deficiency of vitamin B12 primarily occurs due to its improper absorption, rather than its poor consumption .
Definition: Vitamin B12 deficiency is characterized by low levels of vitamin B12 in the body. It is an essential vitamin required for optimal functioning of nervous tissues. Therefore, deficiency of the vitamin can have serious consequences on the neurological functioning.
Cause: A diet deficient in vitamin B12, and all those factors that interfere with the absorption of the vitamin, causes its deficiency to set in. In addition, various other underlying disease conditions, such as pernicious anemia, and condition of chronic alcoholism, can cause deficiency of vitamin B12 to develop.
Symptoms: In the initial stages, vitamin B12 deficiency manifests with signs of fatigue, weight loss, diarrhea, sores in the mouth and tongue, menstrual disorders and increased susceptibility to infections. In advanced stages, when neurological problems set in, individuals experience confusion, irritability, forgetfulness, tingling sensation in the hands and feet, and difficulty in walking properly.
Diagnosis: Vitamin B12 deficiency is diagnosed through blood tests and bone marrow biopsy. These tests also help determine the shape of the red blood cells, and presence of pernicious anemia. A new test known as breath test is also used for diagnosis of vitamin B12 deficiency.
Treatment: The condition is treated with supplements, administered either through the oral or intravenous route. Parenteral administration of vitamin B12 has been shown to enhance the absorption of this vitamin.