Vitamin B-12 is a water-soluble vitamin that is found in certain foods, particularly shellfish, fin fish, meat and dairy. According to MayoClinic.com, the human body stores vitamin B-12, so it is uncommon for people to have a deficiency. However, vegans may not get sufficient amounts of vitamin B-12 in their diets and may rely on supplements for the source of the nutrient. There are three types of vitamin B-12.
Methylcobalamin
Methylcobalamin is a biologically active form of vitamin B-12 that makes various substances in the body such as red blood cells, nerve cells, proteins, fats, hormones and DNA , according to the George Mateljan Foundation. A methylcobalamin deficiency can cause pernicious anemia, a disease that affects red blood cells and has symptoms that include diarrhea, fever, weight loss, weakness, pale skin, numbness in the hands and feet, confusion, memory loss, according to the University of Maryland Medical Center website. Research by S.J. James published in the "American Journal of Clinical Nutrition" in 2009 found that methylcobalamin can benefit autistic children by improving metabolic abnormalities involved with the neurobehavioral disorders associated with autism.
Cyanocobalamin
A popular type of vitamin B-12 in supplements is cyanocobalamin. This form of B-12 is available by pill over-the-counter or injection with a prescription. Inside the body, cyanocobalamin produces methylcobalamin and 5-Deoxyadenosylcobalamin. The University of Maryland Medical Center website states that vitamin B-12 supplementation can be used to treat pernicious anemia, fatigue, heart disease caused from elevated homocysteine levels in the blood, reduce risks of breast cancer, improve sperm count and fertility, improve cognition and reduce symptoms of asthma. Cyanocobalamin is helpful for vegetarians who do not consume shellfish, fin fish, meat or dairy products. Research by S.J. Eussen published in "Archives of Internal Medicine" in May 2005 discovered that supplementation of oral cyanocobalamin in doses of 2.5 mcg, 100 mcg, 250 mcg, 500 mcg and 1000 mcg reduces methylmalonic acid, a metabolite excreted in the urine that is inversely associated with vitamin B-12 levels in the body. Furthermore, the research demonstrates that the lowest dose of oral cyanocobalamin required to normalize vitamin B-12 deficiency is over 200 times greater than the recommended dietary allowance of 3 mcg per day.
Hydroxocobalamin
Hydroxocobalamin is a type of vitamin B-12 available for injection to treat cyanide poisoning. Research by S.W. Borron published in "Annals of Emergency Medicine" in June 2007 discovered that intravenous infusion of hydroxocobalamin is associated with survival of 67 percent of patients confirmed to have cyanide poisoning. Moreover, the research showed that hydroxocobalamin injection does not have any serious adverse effects and is safe for out-of-hospital treatment of people that are presumed to have been exposed to smoke inhalation of cyanide poisoning.
References
- MayoClinic.com: Vitamin B12
- The George Mateljan Foundation: Vitamin B12
- University of Maryland Medical Center: Vitamin B12 (Cobalamin)
- "American Journal of Clinical Nutrition"; Efficacy of Methylcobalamin Treatment in Children with Autism; James, S.J.; Jan 2009
- "Archives of Internal Medicine"; Oral Cyanocobalamin Supplementation in Older People with Vitamin B12 Deficiency; Eussen, S.J.; May 23 2005
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