Vitamin B₁2 Deficiency: Causes, Effects, and Dietary Management
Importance of Vitamin B12
Vitamin B12 is an essential vitamin, which is also known as cobalamin. Vitamin B12 play many essential roles in the human body and helps in:
- the formation of red blood cells
- DNA synthesis
- improving human memory
- boosting energy levels
- preventing heart disease
- supporting the normal functions of nerve cells
Vitamin B12 deficiency in human body may lead to serious health disorders. A great care should be taken to to prevent yourself from these illnesses by maintaining the level of Vitamin B12 in the body.
The common cause of vitamin B12 deficiency anemia is the lack of intrinsic factor, a glycoprotein in the gastric juice, which is essential for the vitamin's absorption. The deficiency may also be found in strict vegetarians because vitamin B12 is found only in foods of animal origin. Other causes include partial or total gastrectomy, conditions with bacterial overgrowth in the small bowel (which create a situation of biological competition-blind loop and small bowel diverticulosis) and non-tropical sprue.
With vitamin B12 deficiency a person's red blood cells become large and fewer in number. The large, immature cells are called macrocytes. When the bone marrow becomes crowded with these abnormal cells they are released into the blood. The level of serum B12 may be determined to confirm the deficiency.
In pernicious anemia (the lack of intrinsic factor, resulting in vitamin B₁2 deficiency) the onset is insidious and often the degree of the anemia is great before the patient consults a doctor. There may be intermittent soreness of the tongue and occasionally periodic diarrhoea. The skin and membranes are pale, and the skin of severely anemic patients may have a faint lemon-yellow tint. The central nervous system is also affected. Patients with pernicious anemia very often develop numbness or tingling in the hands and feet, a diminution of the senses of vibration and position, poor muscular coordination, poor memory, and hallucination. If the deficiency of vitamin B12 continues long enough, the damage to the nerves may be irreversible even with treatment.
Patients with pernicious anemia may be given vitamin B12 in the form of an injection. Within 48 hours of the first injection of hydroxocobalamin, the bone marrow shows a striking change from the megaloblastic to the normoblastic state. Within two to three days the reticulocyte count begins to increase, reaching a maximum within five to seven days. About two weeks after the treatment has started, the reticulocyte count returns to one per cent or less. Hydroxocobalamin is given in a dosage of 1,000 ug twice during the first week, then 1,000 g weekly, until the blood count is normal. When a neurological deficit is present, hydroxocobalamin should be given twice weekly for at least six months.
It is vital that patients with vitamin B12 deficiency due to lack of intrinsic factor i.e pernicious anemia) should continue to receive regular doses of hydroxycobalamin for the rest of their lives to keep the level of haemoglobin about 14 g. 100 ml. This may be achieved by giving 1.000 ug of hydroxocobalamin intramuscularly every four to eight weeks.
The Role of Diet
For sufferers from pernicious anemia, the diet should be high in calories (about 3000-3,500 kcal in males and 2,500-3.000 in females) and in proteins. The high protein diet (1.5 g protein per kg body weight per day) is desirable both to help the liver function and to regenerate the blood. A high carbohydrate content, about 400 g per day, helps to bring the weight up to normal. The fat content should be low and made up of largely emulsified fats. Vitamins and minerals should be provided in adequate amounts. Iron supplements are usually given and, since green leafy vegetables contain should contain an increased amount of these. Liver should be included frequently because it is rich iron and vitamin B12 and should be particularly encouraged. The consistency of diet depends on the condition of the patient if there is any soreness in the mouth and any loss of appetite, the initial diet must be liquid. As the patient improves, the diet may be gradually changed to soft and then to ordinary foods.