What Causes B12 Deficiencies?

Vitamin B12, or cobalamin, is vital for metabolic processes affecting nerve tissue, such as the synthesis of neurotransmitters and the formation of myelin sheaths. Along with folic acid, it assists in the formation of red blood cells and helps the body use iron. B12 aids in the digestion of carbohydrates and fats, helps cells live longer and ensures fertility and normal sleep. B12 deficiency may cause anemia, shortness of breath, tinnitus, headaches, bone loss and fatigue. Deficiency can lead to the development of neurological symptoms including tingling sensations, uncoordinated movements, weakness in extremities, loss of balance and memory, mood changes and psychiatric disturbances.

Vegan Diet

B12 is stored in the body for years, once it is absorbed; deficiency may not be apparent immediately. B12 is found in brewer's yeast, clams, eggs, fish, organ meats and dairy products. Seaweeds, soy products and some herbs have lesser amounts of B12. Long-term strict avoidance of animal products was studied by researchers in Finland, as reported in the "Journal of Nutrition," who took blood samples at 2 year intervals from adherents of a vegan raw food diet. B12 stores were found to decline slowly in the vegans; however, subjects who consumed large amounts of chorella had twice the levels of B12 than those who didn't eat the blue-green algae.

Intrinsic Factor Deficiency

Intrinsic factor is a protein produced in the digestive tract that is needed for proper absorption of Vitamin B12. A lack of intrinsic factor can lead to B12 deficiency. According to the National Institutes of Health, B12 deficiency affects the ability of red blood cells to divide properly. Under a microscope, red blood cells appear too large and in too few numbers. The loss of digestive tissue that produces intrinsic factor may occur through gastric surgery or disease processes. Inflammatory bowel disease (ulcerative colitis or Crohn's Disease) or Celiac disease can thicken, ulcerate, injure or otherwise damage the bowel. Long-term abuse of alcohol can also destroy the body's ability to absorb vitamin B12.
Some people are born with the inability to produce intrinsic factor. This condition is called Pernicious anemia. According to nutritionist Phyllis Balch, author of "Prescription for Nutritional Healing," pernicious anemia is genetically linked and is more common in people of Northern European backgrounds, especially those who are fair-haired and light-skinned.

Lack of Stomach Acid

Over time, decreased hydrochloric acid in the stomach can impair the digestion of foods containing B12. Aging and poor dietary habits are associated with this condition and resulting deficiencies. According to Balch, when undigested food passes through the bowel, it creates an overgrowth of bacteria that further depletes the food of any available B12. Sublingual supplements or injections are usually necessary to correct deficiency.