From: gts (gts_2000@yahoo.com)
Date: Sun Apr 20 2003 - 01:59:45 MDT
"Robert J. Bradbury" <bradbury@aeiveos.com> wrote:
> (Harvey or gts or someone may want to confirm this).
I haven't time to follow this thread closely (I'm
breaking many social graces even to be online at all
during this Easter weekend during which I am not at my
own home) but I see above that I have been mentioned,
so I thought I should scratch up a quick reply.
I scanned the messages here thus far and I'm a little
confused. The original message by Reason pointed to an
article at www.longevitymeme.org, which pointed in
turn to an article at LEF, which comes from
NewsRx.com. That article is about the possible
life-extension benefits of restricting one or more of
three specific amino acids. The title of the LEF
article itself is "A methionine restricted diet may
cause prolongation of life." The two other amino acids
mentioned as AA-restriction candidates are cysteine
and tryptophan.
Am I looking at the right article? Perhaps not.
However if I am looking at the right article then why
is no one here discussing the properties of
methionine, cysteine or tryptophan?
I have often argued (not here at ExI, but rather on
other discussion lists devoted entirely to health and
longevity, some which I manage or moderate) that any
amino acid (AA) considered individually should be
considered as something near to a pharmaceutical drug.
The FDA made a similar argument in its attempt some
years ago to regulate them, and while I oppose the
regulation of AA's I don't think the FDA was too far
off the mark in its arguments. I am inclined to give
some validity to the FDA's argument because the body
expects to receive AA's as part of complete protein
molecules in the company of other AA's and because
each AA has unique activities in the body. It's a bit
of a stretch to say that individual AA's are "natural
foods," given that no animal can consume individual
AA's in a natural diet. It follows also then that a
major restriction in the diet of a single AA might
also have near-drug-like effects, and that the
individual properties of the restricted AA could be
very important.
But I see discussion here only about the general
restriction of amino acids -- nothing about what might
happen if we restrict one or more of the specific AA's
mentioned in the LEF article. (Again, am I looking at
the wrong article?)
Concerning the three AA's mentioned:
Cysteine can act as a neurotoxin ("excitotoxin" to be
more precise), at least when present in large
quantities. This raises the possibility that
restricting cysteine might help to preserve the
nervous system and thus help to extend life-span.
Methionine is one of only a few sulphur containing
AA's. Perhaps restricting intake of sulphur-containing
AA's has relevance to life-extension.
Tryptophan is a precursor to 5-HTP, which is in turn a
precursor to serotonin in the brain. It tends to be a
mild sleep-agent and can help fight depression. Some
studies show that depletion of tryptophan can trigger
psychological depression, and perhaps this type of
depression also works in physical ways similar to
calorie restriction.
These are only thoughts off the top of my head, but
they are the kinds of ideas I would be investigating
more closely if I had time right now to investigate
this subject in detail.
Hope this helps.
-gts
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