B12

DESCRIPTION:
Vitamin B12, or cobalamin, is one of the most important nutrients we obtain from animal-derived foods. Vitamin B12 participates in many bodily processes alongside folic acid, including DNA synthesis, red blood cell formation, and the insulating sheath (myelin sheath) that surrounds nerve cells and enables signal transmission through the nervous system. B12 is found almost exclusively in animal-derived foods such as liver, kidneys, meat, fish, shellfish and crustaceans, dairy products, and eggs. The true source of B12 in nature are bacteria, which are the only organisms capable of producing this vitamin. In humans and animals, these bacteria produce B12 in the large intestine, from which little to no absorption occurs through the intestinal wall; therefore, we must obtain our B12 through animal-derived foods. Vitamin B12 deficiency often occurs in vegetarians who do not consume fish or dairy products. The body’s reserves of vitamin B12 are substantial, so symptoms of deficiency due to insufficient dietary intake typically manifest after approximately 10 years. Fasting is required before blood collection.

DETERMINATION:
SAMPLE: Blood (serum) – must be protected from light

CLINICAL SIGNIFICANCE:
Severe vitamin B12 deficiency manifests as pernicious anemia. However, before the onset of anemia, various issues may arise: neurological in nature (numbness, tingling, burning sensation in the legs, tremors, muscle weakness, sleep disturbances, memory loss, irrational anger, impaired mental function, and Alzheimer’s disease) or psychological problems (dementia, depression, psychoses, and obsessive-compulsive behavior). Pernicious anemia occurs when an individual lacks intrinsic factor and cannot absorb B12. The most common cause of pernicious anemia is an autoimmune reaction that affects and destroys the gastric cells producing intrinsic factor. The disease is characterized by immature, abnormally large red blood cells (macrocytes), which are highly inefficient in oxygen transport, and white blood cells with abnormal nuclei. Causes of deficiency may include: – vegetarian diet (10-20 years of such a diet, especially during pregnancy) – poor nutrition (elderly individuals) – intestinal malabsorption (Crohn’s disease, bowel resection, etc.)

RESULT:
REFERENCE VALUES: Men and women: 145–637 pmol/L