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Vitamin B12

Common Name: Vitamin B12
Synonyms:Cobalamin

Overview:

Vitamin B12 is one of the water soluble B vitamins. Its other name, cobsosmin, indicates that this vitamin contains cobalt in its chemical structure. Of allthe vitamins B12 is the most complex. In chemical structure B12 is closely related to hemoglobin and chlorophyll. B12 is part of what is called the B complex family of vitamins. This complex is essential in the breakdown of fats and proteins. They also play an important role in keeping muscles toned, maintaining the lining of the gastrointestinal tract. They also promote the health of the nervous system, skin, eyes, mouth liver and hair.

B12 not only plays an important role in nerve health but aids in production of DNA and RNA. It also works together with folate in the formation of red blood cells while involved in improving the functioning of the immune system. It also helps the body to withstand stressful conditions. Together with vitamins B6 and folate, B12 helps to control the levels of homocysteine. Elevated homocysteine levels have been linked to an increased risk of heart disease, depression and maybe even Alzheimer’s.

In order for Vitamin B12 to be absorbed by the body, the digestive track must contain what it known as “intrinsic factor. Without this factor, B12 can not be absorbed and a vitamin B12 deficiency is the result. A deficiency of vitamin B12 causes a myriad of symptoms including:

  • Fatigue
  • Shortness of breath
  • Diarrhea
  • Nervousness
  • Numbness or tingling in the fingers and toes.

People who develop pernicious anemia lack the intrinsic factor and therefore cannot absorb vitamin B12. They need to take B12 by injection to ensure that they get enough of this vitamin. It has been found that in people over the age of 60 the neurological symptoms of vitamin B12 deficiency may occur without anemia. The symptoms of this type of B12 deficiency include tingling and numbness in the arms and legs, loss abnormal gait, irritability, depression and loss of cognitive functions (inability to concentrate, memory loss) and dementia. Vitamin B12 deficiency has also been associated with age related hearing loss.

Benefits

The most important use of vitamin B12 is in the treatment of pernicious anemia. Lack of the “intrinsic factor” keeps the vitamin B12 from being absorbed into the body. Eventually this lack of the B vitamin results in a severe anemia. The only treatment for pernicious anemia is vitamin B12 injections for an entire lifetime. Vitamin B12 supplements are especially important in the elderly and those who have undergone gastric surgery. It has been estimated that between 10-15% of people over 60 have a subtle vitamin B12 deficiency. This is because as we age, the stomach production of acid-pepsin decreases. The acid-pepsin combination is what frees vitamin B12 from the foods we eat.

It was once thought that the neurological and physical symptoms of vitamin B12 deficeincy did not occur separately from the development of pernicious anemia. That has now been proven wrong. The neurological symptoms alone are the most common form of vitamin B12 deficiencies. Supplementation with vitamin B12 successfully reverses the memory loss that accompanies the lack of vitamin B12.

Researchers have shown that people with high levels of homocysteine in their blood are 1.7 times more likely to suffer from cardiovascular disease and 2.5 times more likely to suffer a stoke then those whose homocysteine levels are normal. The B vitamins, especially B12 and folate have a strong influence in the maintaining of a normal homocysteine level.

B12 is part of the complex of B vitamins and folate that are important in maintaining eye health and preventing the formation of cataracts. Supplementing with the B vitamins, folate, plus the antioxidants A,C, and E may offer even more protection from cataract development.

Dietary Sources

Fish
 Fish
Dairy
 Dairy
Eggs
 Eggs
Beef and Pork
 Beef and Pork
Organ MeatOrgan Meat

Recommended Dosage:

Daily recommendations for dietary vitamin B12 are listed below.

Pediatric

  • Newborns to 6 months: 0.4 mcg (adequate intake)
  • Infants 6 months to 1 year: 0.5 mcg (adequate intake)
  • Children 1 to 3 years: 0.9 mcg (RDA)
  • Children 4 to 8 years: 1.2 mcg (RDA)
  • Children 9 to 13 years: 1.8 mcg (RDA)
  • Adolescents 14 to 18 years: 2.4 mcg (RDA)

Adult

  • 19 years and older: 2.4 mcg (RDA)*
  • Pregnant females: 2.6 mcg (RDA)
  • Breastfeeding females: 2.8 mcg (RDA)

10-30% of older people do not absorb B12 from food very efficiently. It is recommended that those older than 50 years should add B12 supplements to their diets to ensure proper levels of vitamin B12 in their system.

Contra-indications

  • Vitamin B12 is considered safe and non-toxic. Taking a single B vitamin for long periods of time can cause an imbalance in the entire complex of B vitamins. When supplementing with a particular B vitamin it is recommended that a B complex is taken as well.
  • The B vitamins can interfere with the absorption of tetracycline. Because of this take the B vitamin at a different time than the antibiotic.
  • long term use of antibiotics can deplete the stores of B vitamins. Talk with your healthcare practitioner about supplement with a B complex when on long term antibiotic therapy.
  • Taking stomach acid reducers can decrease the absorption of B12.Medications used in treating cancer, particularly methotrexate, can lower the blood levels of vitamin B12.
  • Taking metformin for diabetes has been shown to lower the blood levels of B12.
  • Phenobarbital and Phenytoin used for the treatment of seizure disorders may interfere with the body’s ability to use vitamin B12.

Web References

  1. http://www.umm.edu/altmed/ConsSupplements/VitaminB12Cobalamincs.html
  2. http://en.wikipedia.org/wiki/Vitamin_B12
  3. http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/vit_0262.shtml
  4. http://healthlibrary.epnet.com/GetContent.aspx?token=e0498803-7f62-4563-8d47-5fe33da65dd4&chunkiid=33802#B

Printed Reference Material

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