S-adenosylmethionine (SAM-e) is an intermediate metabolite of the essential amino acid methionine. SAM-e functions as a methyl doner in many biological reactions and is a precursor for polyamines (33). SAM-e's involvement in the process of methylation assists the body to grow and repair cells, helps maintain phospholipids in the cell membrane and helps maintain the action of several hormones and neurotransmitters that affect mood, including dopamine, serotonin, and melatonin (34). SAM-e is found in every living cell, with its greatest concentrations located in the brain and liver.
S-Adenosylmethionine (SAMe) is a naturally occurring compound that is involved in many biochemical processes in the body. SAMe plays a role in the immune system, maintains cell membranes, and helps produce and break down brain chemicals such as serotonin, melatonin, and dopamine as well as vitamin B12. SAMe also participates in the making of genetic material, known as DNA, and cartilage. Low amounts of folate (vitamin B9) in the body may lead to reduced levels of SAMe. SAMe offers a variety of potential therapeutic uses, primarily in the treatment of the health conditions listed below. It is important to note that SAMe has not been tested carefully over long periods of time. For this reason, it is not yet known whether using SAMe for an extended length of time (months or years) is safe.
S-adenosyl-L-methionine (SAMe) is a natural substance present in the cells of the body. It is a direct metabolite of the essential amino acid L-methionine. It is variously known as ademetionine, S-adenosylmethione, SAM, SAMe and SAM-e. SAMe plays a crucial biochemical role in the body by donating a one-carbon methyl group in a process called transmethylation. SAMe, formed from the reaction of L-methionine and adenosine triphosphate catalyzed by the enzyme S-adenosylmethionine synthetase, is the methyl-group donor in the biosynthesis of both DNA and RNA nucleic acids, phospholipids, proteins, epinephrine, melatonin, creatine and other molecules.
Methylation of DNA is critical in the biological phenomenon known as gene silencing. Gene silencing helps suppress genes that may give rise to cancer or those that may carry information for endogenous retroviruses. Methylation of RNA, particularly transfer RNA, is similarly important in safeguarding the form and function of these molecules in protein synthesis.
SAMe is the methyl donor to phosphatidylethanolamine in the formation of phosphatidylcholine (PC). PC is a major component of cell membranes and is vital for maintenance of cellular membrane fluidity, important in sustaining the bioenergetics and information-processing functions of cells.
SAMe is also involved in the methylation of histones, major elements in chromosomal structure. This methylation is believed to play a key role in the regulation of DNA transcription, the process by which RNA is formed. The carbon and nitrogen atoms of L-carnitine are derived from methylated lysine residues, which are formed by methylating certain proteins with SAMe's methyl group. SAMe's importance in the body is further emphasized by the fact that it is also the methyl donor for the synthesis of epinephrine (adrenaline), creatine, melatonin, glutathione, the polyamines spermine and spermidine, and the amino acids L-cysteine and taurine, all of which play vital roles in human health.
SAMe may be beneficial for mild depression as well as seasonal and postpartum depression. SAMe appears to have some beneficial effects against arthritic inflammation and fibromyalgia. It also appears to lower homocystein levels which when elevated, can increase your risk of heart attack and stroke. SAMe is an interesting and possibly promising substance. Further studies with a double-blind design are needed to confirm this preliminary indication that SAMe is a relatively safe and fast-acting antidepressant.