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 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=24293