Vitamin B12, or cobalamin, helps to keep your nerve and red blood cells healthy and is necessary for DNA formation. Unlike most vitamins, B12 absorption begins in your mouth through the mucous membrane, according to the U.S. Department of Agriculture. Because of this, the sublingual form is often promoted as a superior choice of vitamin. A 2003 study published in British Journal of Pharmacology discovered no real difference in blood levels of B12 when sublingual and swallowed pills were compared. Another study, reported in "Journal of Alternative and Complementary Medicine" in 2006, compared oral and sublingual B-complex that contained 1000 mcg of B12. Researchers used both forms to test their efficacy in reducing homocysteine. Homocysteine levels were lowered equally in both groups, indicating that the sublingual form offers no superiority.
Treatment for Pernicious and Megaloblastic Anemias
Some people are unable to absorb vitamin B12 due to pernicious anemia.This form of anemia occurs due to the lack of a substance that normally binds with B12 before it can be absorbed and utilized by the body. The Mayo Clinic cites B12 supplementation as the appropriate treatment for this disorder. The Mayo Clinic also recommends B12 supplementation as a treatment for megaloblastic anemia. In this form of anemia, red blood cells are abnormally large. Laboratory testing should be performed to determine the underlying cause of megaloblastic anemia, because there are several other causes of this disorder. If B12 deficiency is found, then supplementation with B12 is the preferred treatment.
B12 a Necessity for Vegans and Older Adults
Vitamin B12 is a nutrient found primarily in animal foods such as meat, seafood and dairy products. The Vegan Society, the Vegetarian Resource Group, and the Physicians Committee for Responsible Medicine, among others, recommend that vegans supplement their diets with B12 to avoid deficiency. "Vegan Health" published an article discussing purported plant sources of B12 such as tempeh and seaweed, and all sources tested were found to be inadequate for raising B12 levels in humans.
Another population in need of B12 supplementation is older adults. Men and women over 51 are advised to eat foods fortified with B12 or take supplements to meet the RDA, because the elderly face a heightened risk of deficiency, according to the USDA.
Protection for Aging Brains
High vitamin B12 levels as you age may protect against the brain atrophy linked to Alzheimer's disease and reduced mental facility. One 2008 study from A. Vogiatzoglou and colleagues, published in "Neurology" investigated B12 levels and brain shrinkage in older people.
Those with the lowest measured B12 levels showed the greatest mental decline and brain shrinkage.
In another study, published in "American Journal of Clinical Nutrition" in 2007, researchers at Oxford sought to establish a relationship between elevated homocysteine, B12 levels and mental decline. High levels of homocysteine have been associated with mental impairment, and in this study it was found that low B-12 accompanied high homocysteine in those who rapidly lost mental function. When sublingual and oral routes have been compared, both methods have been shown to reduce homocysteine levels, and The American Heart Association recommends B12 supplementation for this purpose.
References
- "The Lancet"; Sublingual Cobalamin for Pernicious Anaemia;Anthony G Freeman; 1999
- Vegan Health: B12 in Tempeh, Seaweeds, Organic Produce, and Other Plant Foods
- USDA: Vitamin B12
- Mayo Clinic: Vitamin B12
- "British Journal of Clinical Pharmacology"; Replacement Therapy for Vitamin B12 Deficiency; Sharabi A, Cohen E, Sulkes J, Garty M; 2003
- "Neurology"; Vitamin B12 Status and Rate of Brain Volume Loss in Community-Dwelling Elderly;Vogiatzoglou A, Refsum H, Johnston C, Smith SM, Bradley KM, de Jager C, Budge MM, Smith AD; 2008
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