Re: "Healthy" Omega-3 oils cut your life short

[John H. Gohde]

On May 21, 3:53 am, Taka <taka0...@gmail.com> wrote:
> On May 20, 8:10 am, More Granularity <moregranular...@gmail.com>
> wrote:
>
> > FIGHT AGING! NEWSLETTER
> > May 20th 2013
> > MEMBRANE PACEMAKER HYPOTHESIS AND AMES DWARF MICE
> > Tuesday, May 14, 2013http://www.fightaging.org/archives/2013/05/membrane-pacemaker-hypothe...
>
> > Ames dwarf mice lack growth hormone and as a consequence live much
> > longer than their peers. Here the biochemistry of this lineage is
> > considered in light of the membrane pacemaker hypothesis of aging,
> > which suggests that the degree of resistance to oxidative damage in
> > cell membranes is a driving factor in determining longevity. Thus
> > similar species with different proportions of more resistant and less
> > resistant molecules making up their cell membranes have different life
> > spans. Is it possible that this can happen within a species thanks to
> > genetic engineering of the sort that produced the Ames dwarf mouse
> > lineage?
>
> > "Membrane fatty acid (FA) composition is correlated with longevity in
> > mammals. The "membrane pacemaker hypothesis of ageing" proposes that
> > animals which cellular membranes contain high amounts of
> > polyunsaturated FAs (PUFAs) have shorter life spans because their
> > membranes are more susceptible to peroxidation and further oxidative
> > damage. It remains to be shown, however, that long-lived phenotypes
> > such as the Ames dwarf mouse have membranes containing fewer PUFAs and
> > thus being less prone to peroxidation, as would be predicted from the
> > membrane pacemaker hypothesis of ageing.
>
> > Here, we show that across four different tissues, i.e., muscle, heart,
> > liver and brain as well as in liver mitochondria, Ames dwarf mice
> > possess membrane phospholipids containing between 30 and 60 % PUFAs
> > (depending on the tissue), which is similar to PUFA contents of their
> > normal-sized, short-lived siblings. However, we found that that Ames
> > dwarf mice membrane phospholipids were significantly poorer in n-3
> > PUFAs. While lack of a difference in PUFA contents is contradicting
> > the membrane pacemaker hypothesis, the lower n-3 PUFAs content in the
> > long-lived mice provides some support for the membrane pacemaker
> > hypothesis of ageing, as n-3 PUFAs comprise those FAs being blamed
> > most for causing oxidative damage. By comparing tissue composition
> > between 1-, 2- and 6-month-old mice in both phenotypes, we found that
> > membranes differed both in quantity of PUFAs and in the prevalence of
> > certain PUFAs. In sum, membrane composition in the Ames dwarf mouse
> > supports the concept that tissue FA composition is related to
> > longevity."
>
> > At some point a research group will find a way to alter only membrane
> > constituent molecules and no other factors in laboratory mice, which
> > should go some way towards quantifying the effect on aging and
> > longevity. The challenge with using any of the well known long-lived
> > lineages of mice is that many aspects of their metabolism are
> > different - it is difficult to point to any one of those and talk
> > about how important it may or may not be to extended longevity given
> > the presence of the others.
>
> You see?  Fish oil eaters are doomed to fail ....    Taka
>
> ------------------------
>
> Age (Dordr). 2013 May 3. [Epub ahead of print]
>
> Phospholipid composition and longevity: lessons from Ames dwarf mice.
>
> Valencak TG, Ruf T.
> Department of Integrative Biology and Evolution, Research Institute of
> Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse 1,
> 1160, Vienna, Austria,
>
> Membrane fatty acid (FA) composition is correlated with longevity in
> mammals. The "membrane pacemaker hypothesis of ageing" proposes that
> animals which cellular membranes contain high amounts of
> polyunsaturated FAs (PUFAs) have shorter life spans because their
> membranes are more susceptible to peroxidation and further oxidative
> damage. It remains to be shown, however, that long-lived phenotypes
> such as the Ames dwarf mouse have membranes containing fewer PUFAs and
> thus being less prone to peroxidation, as would be predicted from the
> membrane pacemaker hypothesis of ageing. Here, we show that across
> four different tissues, i.e., muscle, heart, liver and brain as well
> as in liver mitochondria, Ames dwarf mice possess membrane
> phospholipids containing between 30 and 60 % PUFAs (depending on the
> tissue), which is similar to PUFA contents of their normal-sized,
> short-lived siblings. However, we found that that Ames dwarf mice
> membrane phospholipids were significantly poorer in n-3 PUFAs. While
> lack of a difference in PUFA contents is contradicting the membrane
> pacemaker hypothesis, the lower n-3 PUFAs content in the long-lived
> mice provides some support for the membrane pacemaker hypothesis of
> ageing, as n-3 PUFAs comprise those FAs being blamed most for causing
> oxidative damage. By comparing tissue composition between 1-, 2- and 6-
> month-old mice in both phenotypes, we found that membranes differed
> both in quantity of PUFAs and in the prevalence of certain PUFAs. In
> sum, membrane composition in the Ames dwarf mouse supports the concept
> that tissue FA composition is related to longevity.
> PMID: 23640425



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