Methionine is one of the 10 essential amino acids which cannot be manufactured in the body, and must therefore be obtained from the diet. Like other amino acids, methionine is vital for the formation of the countless proteins which make up not only the body’s dry tissue, but many of its vital enzymes. Logically enough, as it is an essential component of protein, it is protein foods which are the best source of dietary methionine. Meat, poultry, fish and dairy products are known as first class proteins because they contain all of the essential amino acids. A diet containing a good supply of each of these food groups should normally provide sufficient amino acids, including methionine, for most purposes, but vegetarians can also achieve satisfactory intakes through careful food combining.
Particular attention, however, has been focussed on methionine as the precursor of s-adenosyl methionine, also known as SAM or SAM-e, a compound produced naturally in the body by the metabolism of methionine. S-adenosyl methionine was isolated in Europe in the 1950s, and has been used there as a prescription drug, but it has only very recently been seen as a food supplement in the US. A large number of biochemical reactions are known to require its presence, including the transmission of nerve impulses between cells. Conventional medical opinion insists that healthy people should obtain all the SAM-e they need for these purposes from their intake of dietary methionine, but various clinical or sub-clinical conditions may affect the body’s ability to metabolise SAM-e in this way.
In particular, the brains of sufferers from depression have been observed to be deficient in s-adenosyl methionine as well as serotonin, the so-called “feel-good” hormone. There is some good research evidence from Europe that supplementation with between 800 and 1,600 mg per day of SAM-e increased serotonin levels, significantly improved the condition of patients suffering from moderately severe clinical depression, and was also helpful in some more severe cases. This research appears to validate the long standing practice of methionine supplementation by psychiatrists interested in the possibilities of nutritional therapy.
So there appear to be encouraging grounds for believing that methionine or SAM-e may be useful alternatives to conventional drug therapies in some cases of depression, and may offer similar benefits without the side effects of drugs.
But depression is only one of the conditions for which s-adenosyl methionine appears to offer therapeutic value. There’s also good evidence from European studies that supplement doses similar to those used to tackle depression may be useful in tackling problems with liver function, including hepatitis and even cirrhosis. And given SAM-e’s apparent potential for boosting emotional and psychological health, it has been suggested by some therapists that it may be useful in the rehabilitation programs of alcoholics and drug addicts.
At least one large scale study has shown the anti-inflammatory effects of s-adenosyl methionine to provide to relief from the symptoms of osteo-arthritis, and there are some more speculative grounds for believing that it may also be of benefit to sufferers from Parkinson’s disease and multiple sclerosis.
Orthodox medical opinion, however, insists that more research is required before the potential value of s-adenosyl methionine for any of the above conditions can be definitively established. While these concerns may appear to reflect undue caution, it is certainly true in any case that supplements of methionine or any other amino acid should not be taken in isolation for any extended period of time because of the risk of creating an imbalance.
And importantly, in the case of s-adenosyl methionine, it needs to be noted that there is a potential risk of supplementation leading to a build up of homocysteine. This is another amino acid produced naturally in the body, but excess levels of which are known to be a factor in increasing the risk of cardiovascular and related diseases. Fortunately, however, this is a risk which may be easily avoided simply by ensuring a generous intake of the B vitamins, folic acid, B6 and B12. And, as always with the B complex, these do not function correctly in isolation, so that a good dietary supply of the entire complex is also required.
With this important caveat, and although its potential benefits have perhaps been exaggerated in the media, it does appear that supplementation with s-adenosyl methionine may be worth trying for sufferers of the specific conditions highlighted above, whose natural levels of methionine and SAM-e are likely to have been depressed both by their condition itself and other factors.
