I thought I would like to share with you an assignment I did for my nutrition class. We each had to reasearch a Vitamin or Mineral to discover any benefits, toxicity and deficiencies. It was to be only a few pages long, including references.
I was assigned Vitamin B12. So here it is...
Vitamin B12, otherwise known as Cyanocobalamin or Cobalamin is a water-soluble vitamin. Its many functions include roles as a coenzyme in the metabolism of proteins, carbohydrates and fats (Shils, Ross, Caballero & Cousins, 2006). Supplemental B12 injections on premature infants have been shown to stimulate the formation of red blood cells (Haiden et al, 2006), additionally it may act as a protection against cognitive impairment such as forgetfulness and mental confusion (Morris, Jacques, Rosenberg, & Selhub, 2007).
Unlike the other water-soluble vitamins, B12 can be stored in the liver for up to 5 years. To prevent the depletion of these stores it is recommended that a diet containing foods rich with B12 be included. The best food sources are clams, liver, fortified breakfast cereals, salmon, oysters, eggs, red meats, and dairy products.
The Required Daily Allowance (Health Canada Website) for Vitamin B12 is as follows:
Deficiencies associated with Vitamin B12 due to malabsorption and poor diet, often found in the elderly, have been treated in a variety of ways. These patients have been treated successfully by oral intake of vitamin B12 supplements and a change in diet. A more serious deficiency called pernicious anemia, can occur when there is no absorption of Vitamin B12. In this case the glycoprotein (intrinsic factor), normally secreted by the stomach, required to facilitate the uptake of Vitamin B12 in the intestines is missing. Patients lacking intrinsic factor or those who had complete gastrectomies have been successfully treated with intramuscular injections and nasal sprays (Andres et al, 2004). This treatment must be continued for the life of the patients.
There are certain factors which will affect the absorption of Vitamin B12. ; chronic alcoholism, autoimmune diseases, AIDS, gastritis, long term use of antacids, chronic microbial infections all interfere with absorption of Cobalamin.
It would seem that in the case of Vitamin B12, supplements are needed only in the presence of deficiencies. This is supported by numerous research indicating success in treating patients with defiencies and the lack of research indicating possible negative effects of long-term supplemental Cobalamin.
Andres, E., Loukili, N. H., Noel, E., Kaltenbach, G., Maher, B. A., Perrin, A. E., Noblet- Dick, M., Maloisel, F., Schlienger, J-L., Blickle, J-F. (2004) Vitamin B12 (Cobalamin) deficiency in elderly patients. Canadian Medical Association Journal, 171(3): 251.
Haiden, N., Klebermass, K., Cardona, F., Schwindt, J., Berger, A., Kohlhauser- Vollmuth, C., Jilma, B., and Pollak, A.,(July 2006) A randomized, controlled trial of the effects of adding Vitamin B12 & folate to erythropoietin for the treatment of anemia of prematurity. Pediatrics, 118(1) pp. 180-188.
Marieb, E. N., Hoehn, K., (2007). Human Anatomy & Physiology 7th Edition, San Francisco CA: Pearson Benjamin Cummings Publishers
Morris, M. S., Jacques, P. F., Rosenberg, I. H., Selhub, J., (January 2007) Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older americans in the age of folic acid fortification, American Journal of Clinical Nutrition, 85(1), 193-200.
RDA Values for Vitamin B12. Health Canada Website. Retrieved from http://www.hc-sc.gc.ca/dhp-mps/prodnatur/applications/licen-prod/monograph/mono_vitamin_b12-eng.php.
Shils, M. E., Shike, M., Ross, A. C., Caballero, B., Cousins, R. J., (2006) Modern Nutrition in Health and Disease 10th Edition, Lippincott Williams & Wilkins Publishers.