Folate, Vitamin B12, and S-Adenosylmethionine

Folate (vitamin B-9) and cobalamin (vitamin B-12) are essential for the normal development and function of the central nervous system. The metabolism of these vitamins is intimately linked and supports the synthesis of S-adenosylmethionine (SAMe), the major methyl group donor in methylation reactions. This article reviews the metabolic and clinical importance of folate, vitamin B-12, and SAMe, as well as clinical trials in relation to depression and dementia.