Vitamin B₁₂ - Definciency or Pernicious anemia

Vitamin B₁₂ is essential for the production of red blood cells in the bone marrow, neurological function, and DNA synthesis. Vitamin B₁₂ can only be absorbed with the aid of an enzyme known as the intrinsic factor, normally produced by glands in the stomach.

Pernicious anaemia is an autoimmune disease that affects the stomach lining. This leads to failure to produce intrinsic factor, resulting in vitamin B₁₂ mal-absorption. If pernicious anaemia is left untreated, it causes vitamin _B12 deficiency, leading to megaloblastic anaemia and neurological disorders, even in the presence of adequate dietary intake of vitamin B₁₂.

The main causes of vitamin B₁₂ deficiency include

1. mal-absorption from food
2. pernicious anaemia
3. postsurgical mal-absorption
4. and dietary deficiency

Vitamin B₁₂ is found in foods that come from animals, including fish and shellfish, meat (especially liver), poultry, eggs, milk, and milk products.

Who is at risk?

• People taking anti-acids regularly may cause mal-absorption of vitamin B₁₂, as some anti-acids reduce the production of the intrinsic factor.
• People with atrophic gastritis are unable to absorb vitamin B₁₂ that is naturally present in food. Most, however, can absorb the synthetic vitamin B₁₂ added to fortified foods and dietary supplements.
• People with pernicious anaemia.
• People with stomach and small intestine disorders, such as celiac disease and Crohn's disease, may be unable to absorb enough vitamin B₁₂ from food to maintain healthy body stores.
• Surgical procedures in the gastrointestinal tract, such as weight loss surgery or surgery to remove all or part of the stomach, often result in a loss of cells that secrete hydrochloric acid and intrinsic factor.
• Strict vegetarians and vegans are at risk because natural food sources of vitamin B₁₂ are limited to foods from animals.

What are the symptoms of vitamin B₁₂ deficiency?

Symptoms may be very mild, but can include

• Diarrhea or constipation
• Fatigue, lack of energy, or light-headedness when standing up or with exertion
• Loss of appetite
• Problems concentrating
• Shortness of breath, mostly during exercise
• Swollen, red tongue or bleeding gums

The neurological symptoms of vitamin B₁₂ deficiency can occur without anaemia, so early diagnosis and intervention is important to avoid irreversible damage. Symptoms from nerve damage caused by vitamin B₁₂ deficiency that has been present for a longer time include:

• Confusion or change in mental status (dementia) in severe cases
• Depression
• Loss of balance
• Numbness and tingling of hands and feet

Folic acid and vitamin B₁₂

Large amounts of folic acid can mask the damaging effects of vitamin B₁₂ deficiency by correcting the anaemia caused by vitamin B₁₂ deficiency without correcting the neurological damage that also occurs.

Moreover, preliminary evidence suggests that high serum foliate levels might not only mask vitamin B₁₂ deficiency, but could also aggravates the anaemia and worsen the cognitive symptoms associated with vitamin B₁₂ deficiency. Permanent nerve damage can occur if vitamin B₁₂ deficiency is not treated.

For these reasons, folic acid intake from fortified food and supplements should not exceed 1,000 mcg daily in healthy adults.

If you suspect that you may be deficient in vitamin B₁₂, see your doctor who will run blood test

For more researched information on vitamin B₁₂ go to The Office of Dietary Supplements

Back to Home Page Back to Vitamins