Submitted to: Encyclopedia of Dietary Supplements
Publication Type: Book / chapter
Publication Acceptance Date: 3/3/2005
Publication Date: 5/1/2006
Citation: Allen, L.H., Jones, K.M. Vitamin B-12. Encyclopedia of Dietary Supplements. 2005. ISBN:0-8247-5504-9;112-121. Interpretive Summary:
Technical Abstract: Because vitamin B-12 is only found in animal source foods, strict vegetarianism has long been associated with a greater risk of deficiency of this vitamin. The elderly, many of whom lose their ability to absorb vitamin B-12, and the small proportion of the population with pernicious anemia due to lack of intrinsic factor, are also established high risk groups for this vitamin deficiency. It is generally assumned that clinical symptoms of deficiency take many years to appear after intake or absorption becomes inadequate. However, in recent years it has become apparent that vitamin B-12 deficiency is much more prevalent than previously assumed, a high proportion of people in developing countries and even many lacto-ovo vegetartians. Considering the number and size of population groups at risk of deficiency, it is important that we develop the most sensitive and specific methods of assessing vitamin B-12 status and understand the potential adverse functional consequences of this deficiency across the life span.