B12 & Folate Deficiencies

Vitamin B12 and folate are essential to several metabolic functions in the human body. Humans derive vitamin B12 and folate from the diet. Insufficient dietary intake and certain medical conditions can lead to vitamin B12 and folate deficiencies, which may interfere with the normal growth or function of various body tissues.

Causes

Absorption of vitamin B12 from the intestine requires intrinsic factor, a protein produced by the stomach. Patients with defective intrinsic factor production and those who have undergone stomach removal or gastric bypass surgery often develop a vitamin B12 deficiency caused by the absence of intrinsic factor, notes the medical reference text "Hematology Clinical and Laboratory Practice." Intestinal abnormalities can also cause poor vitamin B12 absorption, potentially leading to a deficiency. Strict vegans may develop a vitamin B12 deficiency because of a lack of animal-derived foodstuffs in the diet.

The body possesses a limited capacity to store folate. Deficiencies, therefore, can develop quickly. Intestinal disorders, lack of gastric acid, certain medications and rare genetic abnormalities may also lead to folate deficiencies.

Effects

A vitamin B12 or folate deficiency, or both, commonly leads to megaloblastic anemia, notes New York-Presbyterian Hospital. Bone marrow production of red blood cells requires both vitamin B12 and folate. Deficiencies slow production, leading to a shortage of red blood cells, or anemia. The term "megaloblastic" refers to the fact that the red blood cells produced with this form of anemia prove abnormally large.

Among infants and young children, vitamin B12 and folate deficiencies may lead to poor growth and development, reports the National Institutes of Health's Office of Dietary Supplements. Vitamin B12 deficiency may also adversely affect nervous system function in children and adults. Folate deficiency during pregnancy can lead to birth defects of the brain and spinal cord, such as spina bifida and anencephaly.

Treatment

Replacement therapy with vitamin B12 and folic acid supplements is the primary form of treatment for patients with deficiencies. Doctors commonly administer vitamin B12 preparations by intramuscular injection for patients with impaired intestinal absorption.

Prevention

Eating a healthful, well-rounded diet can prevent nutritionally induced vitamin B12 and folate deficiencies, advises the National Institutes of Health. Vitamin B12 occurs in abundance in animal-derived foods, including meat, fish, poultry, eggs and milk products. Foods rich in folate include leafy vegetables, citrus fruits, beans, whole grains, poultry, shellfish, liver and pork. Manufacturers also add folic acid to enriched cereal, pasta, bread, rice, flour and grain meals.

Warning

Brain and spinal cord birth defects associated with a folate deficiency develop during the first month of pregnancy, notes the National Institute of Child Health & Human Development. During this critical time of development, a woman may not yet realize she is pregnant. To help prevent these potentially devastating birth defects, the U.S. Public Health Service urges all women capable of childbearing to consume a minimum of 400 mcg of folic acid daily.