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Caloric restriction and mitochondrial fatty acid composition

Tom Matthews tmatth at netcom.ca
Thu Jan 21 03:54:17 EST 1999


Aubrey de Grey wrote:

> Best I know of is Mech Ageing Dev 48(3):207-19 from 1989, which found
> that CR *decreases* unsaturation.  This was confirmed in 1993 (Mech
> Ageing Dev 72(2):155-63).   Walter Cefalu presented some very intriguing
> work at the Gerontological Society meeting in 1997 indicating that CR
> increases levels of (the extremely unsaturated) docosahexaenoic acid,
> but it doesn't seem to have appeared in print.

I am confused. How can CR "*decreases* unsaturation" and at the same
time "increases levels of (the extremely unsaturated) docosahexaenoic
acid"?

> > Less saturates = more polyunsaturates = higher proton leak = less ROS =
> > slower ageing.

This would appear to agree with the more DHA (from CR) impling slower
ageing.
 
> I think the most comprehensive destruction of that theory is probably a
> rather recent paper, Pamplona et al, J Lipid Res 1998 Oct;39(10):1989-94.
> Title: "Mitochondrial membrane peroxidizability index is inversely related
> to maximum life span in mammals".

Doesn't more DHA imply *more* peroxidizability? and hence CR would imply
lower maximum life-span by the above finding?
More confusion on my part.

> This follows up on a 1996 study from
> the same group: Mech Ageing Dev 86(1):53-66, "Low fatty acid unsaturation
> protects against lipid peroxidation in liver mitochondria from long-lived
> species: the pigeon and human case".

Which is certainly consistent with the above but again appears to
contradict the finding of what happens under CR. Are you saying that
this more DHA under CR is, in fact, a potentially life-span *decreasing*
effect of CR?

Maybe I am just "thick" this late at night :)

--Tom 
Tom Matthews
 
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