X-Message-Number: 24293
From: "michaelprice" <>
References: <>
Subject: What animal lifespan experiments are really telling us.
Date: Thu, 24 Jun 2004 09:53:43 +0100

Thomas Donaldson offers some speculation as to why 
antioxidants may not extend our human lives as much, 
in percentage terms, as they do rats or mice.

I have two objections to this; one theoretical, one empirical:
1) Theoretical: antioxidants (and by implication free-radicals) may 
    not have a lot to do with aging; there is a surprising lack of 
    empirical support for the free-radical theory of aging, despite 
    the extensive media attention it receives amongst the public and 
    within gerontological circles.  That calorie restriction extends 
    lifespan by reduction of free-radical levels is conjectural, 
    remember.  Vitamin E, which acts purely as an antioxidant, IIRC,
    has not had a good track record of extending lifespan.  The other
    minerals and vitamins (B-vitamins, specifically) that *have* 
    extended lifespan have many other roles, in addition to their 
    antioxidant activities; they boost the effect of enzymes (which is 
    why B-vitamins are termed co-enzymes); their anti-oxidant effect 
    is due purely to the fact that *some* enzymes act as anti-oxidants; 
    most of their effect operates though a whole host of other enzymes 
    (e.g. DNA repair enzymes, enzymes responsible for melatonin and 
    CoQ10 production, operation of the Krebs cycle etc, etc, etc) 

    This probably why the LEF lifespan experiment was such a
    failure - they were testing mostly antioxidants, and not
    very large amounts of them, either.

2) Empirical: the B-vitamins and minerals that have extended life
    span have extended the lives of flies (lifespans of weeks) 
    and rodents (lifespan of a few years) equally, as percentages.
    By the logic that Thomas and a great many other people have
    used we would expect the lives of flies to be extended by a 
    greater proportion than that of rodents.  This does NOT happen.
    Ergo the logic is flawed.  Pick a reason.

Cheers,
Michael C Price
http://mcp.longevity-report.com
http://www.hedweb.com/manworld.htm

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