de Grey on why CRON may only lengthen life by 2-3 years

[Guest guest]

Hi folks:

In short, blame the weather (but I think he means climate) .....

" The unfortunate influence of the weather on the rate of ageing: why

human caloric restriction or its emulation may only extend life

expectancy by 2-3 years.

de Grey AD.

Department of Genetics, University of Cambridge, Cambridge, UK.

ag24@...

Much research interest, and recently even commercial interest, has

been predicated on the assumption that reasonably closely-related

species--humans and mice, for example--should, in principle, respond

to ageing-retarding interventions with an increase in maximum

lifespan roughly proportional to their control lifespan (that without

the intervention). Here, it is argued that the best-studied life-

extending manipulations of mice are examples of a category that is

highly unlikely to follow this rule, and more likely to exhibit only

a similar absolute increase in maximum lifespan from one species to

the next, independent of the species' control lifespan. That category-

-reduction in dietary calories or in the organism's ability to

metabolize or sense them--is widely recognized to extend lifespan as

an evolutionary adaptation to transient starvation in the wild, a

situation which alters the organism's optimal partitioning of

resources between maintenance and reproduction. What has been

generally overlooked is that the extent of the evolutionary pressure

to maintain adaptability to a given duration of starvation varies

with the frequency of that duration, something which is--certainly

for terrestrial animals and less directly for others--determined

principally by the weather. The pattern of starvation that the

weather imposes is suggested here to be of a sort that will tend to

cause all terrestrial animals, even those as far apart

phylogenetically as nematodes and mice, to possess the ability to

live a similar maximum absolute (rather than proportional) amount

longer when food is short than when it is plentiful. This

generalization is strikingly in line with available data, leading

(given the increasing implausibility of further extending human mean

but not maximum lifespan in the industrialized world) to the

biomedically and commercially sobering conclusion that interventions

which manipulate caloric intake or its sensing are unlikely ever to

confer more than 2 or 3 years' increase in human mean or maximum

lifespan at the most. "

PMID: 15711074

[Guest guest]

Hi folks:

Worth remembering, though, that a dutch study posted here about a

year ago found that a BMI of 30 reduced life expectancy by seven

years. Although I do not remember what the base BMI was supposed to

be. I doubt they had used a true CRON BMI for the 'zero years of

reduced life expectancy' base.

Rodney.

--- In , " Rodney " <perspect1111@y...>

wrote:

>

> Hi folks:

>

> In short, blame the weather (but I think he means climate) .....

>

> " The unfortunate influence of the weather on the rate of ageing:

why

> human caloric restriction or its emulation may only extend life

> expectancy by 2-3 years.

>

> de Grey AD.

>

> Department of Genetics, University of Cambridge, Cambridge, UK.

> ag24@g...

>

> Much research interest, and recently even commercial interest, has

> been predicated on the assumption that reasonably closely-related

> species--humans and mice, for example--should, in principle,

respond

> to ageing-retarding interventions with an increase in maximum

> lifespan roughly proportional to their control lifespan (that

without

> the intervention). Here, it is argued that the best-studied life-

> extending manipulations of mice are examples of a category that is

> highly unlikely to follow this rule, and more likely to exhibit

only

> a similar absolute increase in maximum lifespan from one species to

> the next, independent of the species' control lifespan. That

category-

> -reduction in dietary calories or in the organism's ability to

> metabolize or sense them--is widely recognized to extend lifespan

as

> an evolutionary adaptation to transient starvation in the wild, a

> situation which alters the organism's optimal partitioning of

> resources between maintenance and reproduction. What has been

> generally overlooked is that the extent of the evolutionary

pressure

> to maintain adaptability to a given duration of starvation varies

> with the frequency of that duration, something which is--certainly

> for terrestrial animals and less directly for others--determined

> principally by the weather. The pattern of starvation that the

> weather imposes is suggested here to be of a sort that will tend to

> cause all terrestrial animals, even those as far apart

> phylogenetically as nematodes and mice, to possess the ability to

> live a similar maximum absolute (rather than proportional) amount

> longer when food is short than when it is plentiful. This

> generalization is strikingly in line with available data, leading

> (given the increasing implausibility of further extending human

mean

> but not maximum lifespan in the industrialized world) to the

> biomedically and commercially sobering conclusion that

interventions

> which manipulate caloric intake or its sensing are unlikely ever to

> confer more than 2 or 3 years' increase in human mean or maximum

> lifespan at the most. "

>

> PMID: 15711074

>

[Guest guest]

Hi folks:

Worth remembering, though, that a dutch study posted here about a

year ago found that a BMI of 30 reduced life expectancy by seven

years. Although I do not remember what the base BMI was supposed to

be. I doubt they had used a true CRON BMI for the 'zero years of

reduced life expectancy' base.

Rodney.

--- In , " Rodney " <perspect1111@y...>

wrote:

>

> Hi folks:

>

> In short, blame the weather (but I think he means climate) .....

>

> " The unfortunate influence of the weather on the rate of ageing:

why

> human caloric restriction or its emulation may only extend life

> expectancy by 2-3 years.

>

> de Grey AD.

>

> Department of Genetics, University of Cambridge, Cambridge, UK.

> ag24@g...

>

> Much research interest, and recently even commercial interest, has

> been predicated on the assumption that reasonably closely-related

> species--humans and mice, for example--should, in principle,

respond

> to ageing-retarding interventions with an increase in maximum

> lifespan roughly proportional to their control lifespan (that

without

> the intervention). Here, it is argued that the best-studied life-

> extending manipulations of mice are examples of a category that is

> highly unlikely to follow this rule, and more likely to exhibit

only

> a similar absolute increase in maximum lifespan from one species to

> the next, independent of the species' control lifespan. That

category-

> -reduction in dietary calories or in the organism's ability to

> metabolize or sense them--is widely recognized to extend lifespan

as

> an evolutionary adaptation to transient starvation in the wild, a

> situation which alters the organism's optimal partitioning of

> resources between maintenance and reproduction. What has been

> generally overlooked is that the extent of the evolutionary

pressure

> to maintain adaptability to a given duration of starvation varies

> with the frequency of that duration, something which is--certainly

> for terrestrial animals and less directly for others--determined

> principally by the weather. The pattern of starvation that the

> weather imposes is suggested here to be of a sort that will tend to

> cause all terrestrial animals, even those as far apart

> phylogenetically as nematodes and mice, to possess the ability to

> live a similar maximum absolute (rather than proportional) amount

> longer when food is short than when it is plentiful. This

> generalization is strikingly in line with available data, leading

> (given the increasing implausibility of further extending human

mean

> but not maximum lifespan in the industrialized world) to the

> biomedically and commercially sobering conclusion that

interventions

> which manipulate caloric intake or its sensing are unlikely ever to

> confer more than 2 or 3 years' increase in human mean or maximum

> lifespan at the most. "

>

> PMID: 15711074

>