Re: Longer Life Comes From Higher Metabolism, Not Lower

[Guest guest]

Jeff,

I think the link below describes the details of the same article:

Medical Science News

Published: Wednesday, 2-Jun-2004

http://www.news-medical.net/?id=2079

Tony

--- In , " jeffp54252 " <jeffp54252@...>

wrote:

>

> There is a link for the following in the " Extreme CRON vs. Moderate

> CRON " document in the files:

>

> Metabolic Aging Theory Turned Upside Down

> Seven-year study in mice suggests that longer life comes

> from higher metabolism, not lower

>

> http://www.betterhumans.com/News/news.aspx?articleID=2004-05-31-2

>

> Unfortunately, the link no longer works and I have been unable to

> track down the original article. It looks like the study results were

> published about three years ago. Does anyone have anymore info? Have

> these findings been supported by additional research? Unraveling the

> mysteries of aging and longevity can sure be complicated and seemingly

> filled with paradoxes.

>

> Jeff

>

[Guest guest]

Theres a few things I'd want to know before coming to any conclusions

about whats going on here. First, how long did the mice in each group

live on average. Secondly we know that slow metabolism plus ad lib

eating = higher body weight leading to increased disease and death.

However, decreased metabolism and being CR'd has a beneficial effect

as we all know. It could just be that mice eating an ad libitum diet

were more prone to obesity if their metabolism was slow, whereas a

'faster metabolic rate' prevented diseases associated with

overweight/obesity. Thus extended average lifespan. But these mice

with a faster metabolism compared to CR'd mice may not look so good.

Matt

> >

> > There is a link for the following in the " Extreme CRON vs. Moderate

> > CRON " document in the files:

> >

> > Metabolic Aging Theory Turned Upside Down

> > Seven-year study in mice suggests that longer life comes

> > from higher metabolism, not lower

> >

> > http://www.betterhumans.com/News/news.aspx?articleID=2004-05-31-2

> >

> > Unfortunately, the link no longer works and I have been unable to

> > track down the original article. It looks like the study results were

> > published about three years ago. Does anyone have anymore info? Have

> > these findings been supported by additional research? Unraveling the

> > mysteries of aging and longevity can sure be complicated and seemingly

> > filled with paradoxes.

> >

> > Jeff

> >

>

[Guest guest]

Hi Tony and Matt:

Interesting. How did they measure metabolic rate?

Depending on the measurement technique, might the findings be

explained by the healthier mice feeling more enthusiastic and being

more active, while the unhealthy ones hid in the corner feeling sick?

Rodney.

> > >

> > > There is a link for the following in the " Extreme CRON vs.

Moderate

> > > CRON " document in the files:

> > >

> > > Metabolic Aging Theory Turned Upside Down

> > > Seven-year study in mice suggests that longer life comes

> > > from higher metabolism, not lower

> > >

> > > http://www.betterhumans.com/News/news.aspx?articleID=2004-05-31-

2

> > >

> > > Unfortunately, the link no longer works and I have been unable

to

> > > track down the original article. It looks like the study

results were

> > > published about three years ago. Does anyone have anymore info?

Have

> > > these findings been supported by additional research?

Unraveling the

> > > mysteries of aging and longevity can sure be complicated and

seemingly

> > > filled with paradoxes.

> > >

> > > Jeff

> > >

> >

>

[Guest guest]

Hi All, It seems quite reasonable the on a per g body mass basis, with relatively more muscle mass, we are going to expend more energy. The pdf of the paper referred to is below a availed. Cheers, Al. Speakman JR, Talbot DA, Selman C, Snart S, McLaren JS, Redman P, Krol E, DM, MS, Brand MD. Uncoupled and surviving: individual mice with high metabolism have greatermitochondrial uncoupling and live longer.Aging Cell. 2004 Jun;3(3):87-95.PMID: 15153176 Two theories of how energy metabolism should be associated with longevity, both mediated via free-radical production, make completely contrary predictions. The 'rate of living-free-radical theory' (Pearl, 1928; Harman, 1956; Sohal, 2002) suggests a negative association, the 'uncoupling to survive' hypothesis (Brand, 2000) suggests the

correlation should be positive. Existing empirical data on this issue is contradictory and extremely confused (Rubner, 1908; Yan & Sohal, 2000; Ragland & Sohal, 1975; Daan et al., 1996; Wolf & Schmid-Hempel, 1989]. We sought associations between longevity and individual variations in energy metabolism in a cohort of outbred mice. We found a positive association between metabolic intensity (kJ daily food assimilation expressed as g/body mass) and lifespan, but no relationships of lifespan to body mass, fat mass or lean body mass. Mice in the upper quartile of metabolic intensities had greater resting oxygen consumption by 17% and lived 36% longer than mice in the lowest intensity quartile. Mitochondria isolated from the skeletal muscle of mice in the upper quartile had higher proton conductance than mitochondria from mice from the lowest quartile. The higher conductance was caused by higher levels of endogenous activators of proton leak through the adenine

nucleotide translocase and uncoupling protein-3. Individuals with high metabolism were therefore more uncoupled, had greater resting and total daily energy expenditures and survived longest - supporting the 'uncoupling to survive' hypothesis.Rodney <perspect1111@...> wrote: Hi Tony and Matt:Interesting. How did they measure metabolic rate? Depending on the measurement technique, might the findings be explained by the healthier mice feeling more enthusiastic and being more active, while the

unhealthy ones hid in the corner feeling sick?Rodney.> > >> > > There is a link for the following in the "Extreme CRON vs. Moderate> > > CRON" document in the files:> > > > > > Metabolic Aging Theory Turned

Upside Down> > > Seven-year study in mice suggests that longer life comes> > > from higher metabolism, not lower> > > > > > http://www.betterhumans.com/News/news.aspx?articleID=2004-05-31-2> > > > > > Unfortunately, the link no longer works and I have been unable to> > > track down the original article. It looks like the study results were> > > published about three years ago. Does anyone have anymore info? Have> > > these findings been supported by additional research? Unraveling the> > > mysteries of aging and longevity can sure be complicated and seemingly> > > filled with paradoxes.> > > > > > Jeff> > >>

>>

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[Guest guest]

Al,

Thanks for providing this reference (Uncoupled and surviving:

individual mice with high metabolism have greater mitochondrial

uncoupling and live longer. Aging Cell. 2004 Jun;3(3):87-95. PMID:

15153176). One of the key observations was the " positive association

between metabolic intensity (kJ daily food assimilation expressed as

g/body mass) and lifespan, but no relationships of lifespan to body

mass, fat mass or lean body mass. "

Back in August 5, 2004 (Message 14018) I asked the question: " What is

CRON? - 18% more food? " which addressed exactly the fact that animals

started on CR at an early age always eat more food per unit of body

weight than the control animals. I have found this apparent paradox

interesting and have repeatedly tried to engage discussion in this

topic, but never with much success.

I really feel that the stunting of body weight reduces the amount of

food that the smaller animal can eat and that this needs to be taken

into account to calculate the real rate of caloric restriction for the

smaller CRed animals. I explain this in the " technical analysis "

section of my CR web page:

http://www.scientificpsychic.com/health/crondiet.html

It is good to see a publication that tries to resolve the paradox in

terms of metabolism.

Tony

>

> Hi All,

>

> It seems quite reasonable the on a per g body mass basis, with

relatively more muscle mass, we are going to expend more energy. The

pdf of the paper referred to is below a availed.

>

> Cheers, Al.

>

>

> Speakman JR, Talbot DA, Selman C, Snart S, McLaren JS, Redman P,

Krol E,

> DM, MS, Brand MD.

> Uncoupled and surviving: individual mice with high metabolism have

greater

> mitochondrial uncoupling and live longer.

> Aging Cell. 2004 Jun;3(3):87-95.

> PMID: 15153176

>

> Two theories of how energy metabolism should be associated with

longevity, both mediated via free-radical production, make completely

contrary predictions. The 'rate of living-free-radical theory' (Pearl,

1928; Harman, 1956; Sohal, 2002) suggests a negative association, the

'uncoupling to survive' hypothesis (Brand, 2000) suggests the

correlation should be positive. Existing empirical data on this issue

is contradictory and extremely confused (Rubner, 1908; Yan & Sohal,

2000; Ragland & Sohal, 1975; Daan et al., 1996; Wolf & Schmid-Hempel,

1989]. We sought associations between longevity and individual

variations in energy metabolism in a cohort of outbred mice. We found

a positive association between metabolic intensity (kJ daily food

assimilation expressed as g/body mass) and lifespan, but no

relationships of lifespan to body mass, fat mass or lean body mass.

Mice in the upper quartile of metabolic intensities had greater

resting oxygen consumption by 17% and lived 36%

> longer than mice in the lowest intensity quartile. Mitochondria

isolated from the skeletal muscle of mice in the upper quartile had

higher proton conductance than mitochondria from mice from the lowest

quartile. The higher conductance was caused by higher levels of

endogenous activators of proton leak through the adenine nucleotide

translocase and uncoupling protein-3. Individuals with high metabolism

were therefore more uncoupled, had greater resting and total daily

energy expenditures and survived longest - supporting the 'uncoupling

to survive' hypothesis.

>

[Guest guest]

Hi All, The below free full-text paper is another example of Resting Metabolic Rate (RMR) being decreased even by a short period of modest caloric restriction (50 days of 20% CR). According to the abstract, 22.3% of the caloric deficit was compensated by a reduction of the RMR. See the full texts below. Body mass was not significantly different in CRed versus control mice, but fat-free mass was lower. Mice were only 10 weeks old at the beginning of the experiment, and so hardly late-life. Resting Metabolic Rate was lower in the CRed mice and they were less active, it seemed. Why was the body temperature of the CRed mice higher? Why was there less energy/g in the feces, yet no difference in apparent energy absorption? Hambly C, Speakman JR.Contribution of different mechanisms to compensation for energy restriction in the mouse.Obes Res. 2005

Sep;13(9):1548-57.PMID: 16222057 OBJECTIVE: Restriction of energy intake produces weight loss, but the rate of loss is seldom sustained. This is presumed to be a consequence of compensatory reductions in energy expenditure, although the exact contributions of different components to the energy budget remain uncertain. We examined the compensatory responses of mice to a 20% dietary restriction. RESEARCH METHODS AND PROCEDURES: We measured body mass, body fatness, body temperature, and the components of daily energy expenditure for 50 MF1 mice. Forty mice were then placed on a restricted diet at 80% of their ad libitum intake for 50 days. The remaining 10 mice continued to feed ad libitum. Ten days before the end of the restriction period, the same measurements were taken. RESULTS: There were no significant differences between the control and restricted groups in any parameters before restriction. During the restriction period, body mass

increased in both the control and restricted groups, but at a slower rate in the restricted mice. The control group increased in both fat and fat free mass; however, although the restricted group increased fat to the same extent as the controls, fat free mass increased to a lesser extent. The contributions of the different components of the expended energy to compensate for the reduced energy intake were energy deposition, 2.2%; resting metabolic rate, 22.3%; and activity, 75.5%. DISCUSSION: Mice were able to compensate almost completely for the restricted energy intake that was achieved by altering the amount of energy required for each component of the energy budget except digestive efficiency. http://www.obesityresearch.org/cgi/content/full/13/9/1548http://www.obesityresearch.org/cgi/reprint/13/9/1548citpeks <citpeks@...> wrote: Al,Thanks for providing this reference (Uncoupled and surviving:individual mice with high metabolism have greater mitochondrialuncoupling and live longer. Aging Cell. 2004 Jun;3(3):87-95. PMID:15153176). One of the key observations was the "positive associationbetween metabolic intensity (kJ daily food assimilation expressed asg/body mass)

and lifespan, but no relationships of lifespan to bodymass, fat mass or lean body mass."Back in August 5, 2004 (Message 14018) I asked the question: "What isCRON? - 18% more food?" which addressed exactly the fact that animalsstarted on CR at an early age always eat more food per unit of bodyweight than the control animals. I have found this apparent paradoxinteresting and have repeatedly tried to engage discussion in thistopic, but never with much success.I really feel that the stunting of body weight reduces the amount offood that the smaller animal can eat and that this needs to be takeninto account to calculate the real rate of caloric restriction for thesmaller CRed animals. I explain this in the "technical analysis"section of my CR web page:http://www.scientificpsychic.com/health/crondiet.htmlIt is good to see a

publication that tries to resolve the paradox interms of metabolism.Tony>> Hi All,> > It seems quite reasonable the on a per g body mass basis, withrelatively more muscle mass, we are going to expend more energy. Thepdf of the paper referred to is below a availed.> > Cheers, Al.> > > Speakman JR, Talbot DA, Selman C, Snart S, McLaren JS, Redman P,Krol E,> DM, MS, Brand MD.> Uncoupled and surviving: individual mice with high metabolism havegreater> mitochondrial uncoupling and live longer.> Aging Cell. 2004 Jun;3(3):87-95.> PMID: 15153176> > Two theories of how energy metabolism should be associated withlongevity, both mediated via free-radical production, make

completelycontrary predictions. The 'rate of living-free-radical theory' (Pearl,1928; Harman, 1956; Sohal, 2002) suggests a negative association, the'uncoupling to survive' hypothesis (Brand, 2000) suggests thecorrelation should be positive. Existing empirical data on this issueis contradictory and extremely confused (Rubner, 1908; Yan & Sohal,2000; Ragland & Sohal, 1975; Daan et al., 1996; Wolf & Schmid-Hempel,1989]. We sought associations between longevity and individualvariations in energy metabolism in a cohort of outbred mice. We founda positive association between metabolic intensity (kJ daily foodassimilation expressed as g/body mass) and lifespan, but norelationships of lifespan to body mass, fat mass or lean body mass.Mice in the upper quartile of metabolic intensities had greaterresting oxygen consumption by 17% and lived 36%> longer than mice in the lowest intensity quartile.

Mitochondriaisolated from the skeletal muscle of mice in the upper quartile hadhigher proton conductance than mitochondria from mice from the lowestquartile. The higher conductance was caused by higher levels ofendogenous activators of proton leak through the adenine nucleotidetranslocase and uncoupling protein-3. Individuals with high metabolismwere therefore more uncoupled, had greater resting and total dailyenergy expenditures and survived longest - supporting the 'uncouplingto survive' hypothesis.>

Looking for earth-friendly autos? Browse Top Cars by "Green Rating" at Autos' Green Center.

[Guest guest]

The papers cited by Al illustrate the interesting CR paradox:

1) CR decreases Resting Metabolic Rate, which means fewer calories are

required.

2) CR animals eat more calories per unit of body weight than the

controls, i.e., a higher " metabolic intensity " .

Both statements are true and experimentally verified.

Tony

> >

> > Hi All,

> >

> > It seems quite reasonable the on a per g body mass basis, with

> relatively more muscle mass, we are going to expend more energy. The

> pdf of the paper referred to is below a availed.

> >

> > Cheers, Al.

> >

> >

> > Speakman JR, Talbot DA, Selman C, Snart S, McLaren JS, Redman P,

> Krol E,

> > DM, MS, Brand MD.

> > Uncoupled and surviving: individual mice with high metabolism have

> greater

> > mitochondrial uncoupling and live longer.

> > Aging Cell. 2004 Jun;3(3):87-95.

> > PMID: 15153176

> >

> > Two theories of how energy metabolism should be associated with

> longevity, both mediated via free-radical production, make completely

> contrary predictions. The 'rate of living-free-radical theory' (Pearl,

> 1928; Harman, 1956; Sohal, 2002) suggests a negative association, the

> 'uncoupling to survive' hypothesis (Brand, 2000) suggests the

> correlation should be positive. Existing empirical data on this issue

> is contradictory and extremely confused (Rubner, 1908; Yan & Sohal,

> 2000; Ragland & Sohal, 1975; Daan et al., 1996; Wolf & Schmid-Hempel,

> 1989]. We sought associations between longevity and individual

> variations in energy metabolism in a cohort of outbred mice. We found

> a positive association between metabolic intensity (kJ daily food

> assimilation expressed as g/body mass) and lifespan, but no

> relationships of lifespan to body mass, fat mass or lean body mass.

> Mice in the upper quartile of metabolic intensities had greater

> resting oxygen consumption by 17% and lived 36%

> > longer than mice in the lowest intensity quartile. Mitochondria

> isolated from the skeletal muscle of mice in the upper quartile had

> higher proton conductance than mitochondria from mice from the lowest

> quartile. The higher conductance was caused by higher levels of

> endogenous activators of proton leak through the adenine nucleotide

> translocase and uncoupling protein-3. Individuals with high metabolism

> were therefore more uncoupled, had greater resting and total daily

> energy expenditures and survived longest - supporting the 'uncoupling

> to survive' hypothesis.

> >

>

>

>

>

>

>

> ---------------------------------

> Looking for earth-friendly autos?

> Browse Top Cars by " Green Rating " at Autos' Green Center.

>

[Guest guest]

No argument.

Isn't it true the CRed mice are smaller and being smaller eat less and higher metabolic rate?

I think we cannot confuse that with grown humans?

Isn't our drop in RMR due to a "natural" lowering of intake?

regards.

[ ] Re: Longer Life Comes From Higher Metabolism, Not Lower

The papers cited by Al illustrate the interesting CR paradox: 1) CR decreases Resting Metabolic Rate, which means fewer calories arerequired. 2) CR animals eat more calories per unit of body weight than thecontrols, i.e., a higher "metabolic intensity".Both statements are true and experimentally verified.Tony-- In , Al Pater <old542000@...> wrote:>> Hi All,> > The below free full-text paper is another example of RestingMetabolic Rate (RMR) being decreased even by a short period of modestcaloric restriction (50 days of 20% CR). According to the abstract,22.3% of the caloric deficit was compensated by a reduction of the RMR.> > See the full texts below. Body mass was not significantlydifferent in CRed versus control mice, but fat-free mass was lower. Mice were only 10 weeks old at the beginning of the experiment, and sohardly late-life. Resting Metabolic Rate was lower in the CRed miceand they were less active, it seemed. Why was the body temperature ofthe CRed mice higher? Why was there less energy/g in the feces, yetno difference in apparent energy absorption?> > Hambly C, Speakman JR.> Contribution of different mechanisms to compensation for energyrestriction in the mouse.> Obes Res. 2005 Sep;13(9):1548-57.> PMID: 16222057>

..

[Guest guest]

Hi Tony:

Might at least part of the explanation be that the first reflects

results of CR experiments started in adult animals after full growth

has been achieved, while the second reflects experiments where CR is

commenced at a very young age, growth is retarded, and full

adult 'height' is considerably less as a result?

Rodney.

> > Al,

> >

> > Thanks for providing this reference (Uncoupled and surviving:

> > individual mice with high metabolism have greater mitochondrial

> > uncoupling and live longer. Aging Cell. 2004 Jun;3(3):87-95. PMID:

> > 15153176). One of the key observations was the " positive

association

> > between metabolic intensity (kJ daily food assimilation expressed

as

> > g/body mass) and lifespan, but no relationships of lifespan to

body

> > mass, fat mass or lean body mass. "

> >

> > Back in August 5, 2004 (Message 14018) I asked the

question: " What is

> > CRON? - 18% more food? " which addressed exactly the fact that

animals

> > started on CR at an early age always eat more food per unit of

body

> > weight than the control animals. I have found this apparent

paradox

> > interesting and have repeatedly tried to engage discussion in this

> > topic, but never with much success.

> >

> > I really feel that the stunting of body weight reduces the amount

of

> > food that the smaller animal can eat and that this needs to be

taken

> > into account to calculate the real rate of caloric restriction

for the

> > smaller CRed animals. I explain this in the " technical analysis "

> > section of my CR web page:

> > http://www.scientificpsychic.com/health/crondiet.html

> >

> > It is good to see a publication that tries to resolve the paradox

in

> > terms of metabolism.

> >

> > Tony

> > --- In , Al Pater <old542000@>

wrote:

> > >

> > > Hi All,

> > >

> > > It seems quite reasonable the on a per g body mass basis, with

> > relatively more muscle mass, we are going to expend more energy.

The

> > pdf of the paper referred to is below a availed.

> > >

> > > Cheers, Al.

> > >

> > >

> > > Speakman JR, Talbot DA, Selman C, Snart S, McLaren JS, Redman P,

> > Krol E,

> > > DM, MS, Brand MD.

> > > Uncoupled and surviving: individual mice with high metabolism

have

> > greater

> > > mitochondrial uncoupling and live longer.

> > > Aging Cell. 2004 Jun;3(3):87-95.

> > > PMID: 15153176

> > >

> > > Two theories of how energy metabolism should be associated with

> > longevity, both mediated via free-radical production, make

completely

> > contrary predictions. The 'rate of living-free-radical theory'

(Pearl,

> > 1928; Harman, 1956; Sohal, 2002) suggests a negative association,

the

> > 'uncoupling to survive' hypothesis (Brand, 2000) suggests the

> > correlation should be positive. Existing empirical data on this

issue

> > is contradictory and extremely confused (Rubner, 1908; Yan &

Sohal,

> > 2000; Ragland & Sohal, 1975; Daan et al., 1996; Wolf & Schmid-

Hempel,

> > 1989]. We sought associations between longevity and individual

> > variations in energy metabolism in a cohort of outbred mice. We

found

> > a positive association between metabolic intensity (kJ daily food

> > assimilation expressed as g/body mass) and lifespan, but no

> > relationships of lifespan to body mass, fat mass or lean body

mass.

> > Mice in the upper quartile of metabolic intensities had greater

> > resting oxygen consumption by 17% and lived 36%

> > > longer than mice in the lowest intensity quartile. Mitochondria

> > isolated from the skeletal muscle of mice in the upper quartile

had

> > higher proton conductance than mitochondria from mice from the

lowest

> > quartile. The higher conductance was caused by higher levels of

> > endogenous activators of proton leak through the adenine

nucleotide

> > translocase and uncoupling protein-3. Individuals with high

metabolism

> > were therefore more uncoupled, had greater resting and total daily

> > energy expenditures and survived longest - supporting

the 'uncoupling

> > to survive' hypothesis.

> > >

> >

> >

> >

> >

> >

> >

> > ---------------------------------

> > Looking for earth-friendly autos?

> > Browse Top Cars by " Green Rating " at Autos' Green Center.

> >

>

[Guest guest]

Hi Tony:

And there is another issue:

In the NOVA (Scientific American Frontiers?) program, the one in

which Dr. Walford was showing his CR'ed and non-Cr'ed mice, the CR

mice were running all around their cage while the non-CR'ed mice, the

same age, were not far from comatose.

So it is easy to believe that the CR mice have a lower **RMR** AND,

at the same time, a higher overall caloric expenditure because of

their increased exercise.

So is this really a paradox?

Rodney.

> > Al,

> >

> > Thanks for providing this reference (Uncoupled and surviving:

> > individual mice with high metabolism have greater mitochondrial

> > uncoupling and live longer. Aging Cell. 2004 Jun;3(3):87-95. PMID:

> > 15153176). One of the key observations was the " positive

association

> > between metabolic intensity (kJ daily food assimilation expressed

as

> > g/body mass) and lifespan, but no relationships of lifespan to

body

> > mass, fat mass or lean body mass. "

> >

> > Back in August 5, 2004 (Message 14018) I asked the

question: " What is

> > CRON? - 18% more food? " which addressed exactly the fact that

animals

> > started on CR at an early age always eat more food per unit of

body

> > weight than the control animals. I have found this apparent

paradox

> > interesting and have repeatedly tried to engage discussion in this

> > topic, but never with much success.

> >

> > I really feel that the stunting of body weight reduces the amount

of

> > food that the smaller animal can eat and that this needs to be

taken

> > into account to calculate the real rate of caloric restriction

for the

> > smaller CRed animals. I explain this in the " technical analysis "

> > section of my CR web page:

> > http://www.scientificpsychic.com/health/crondiet.html

> >

> > It is good to see a publication that tries to resolve the paradox

in

> > terms of metabolism.

> >

> > Tony

> > --- In , Al Pater <old542000@>

wrote:

> > >

> > > Hi All,

> > >

> > > It seems quite reasonable the on a per g body mass basis, with

> > relatively more muscle mass, we are going to expend more energy.

The

> > pdf of the paper referred to is below a availed.

> > >

> > > Cheers, Al.

> > >

> > >

> > > Speakman JR, Talbot DA, Selman C, Snart S, McLaren JS, Redman P,

> > Krol E,

> > > DM, MS, Brand MD.

> > > Uncoupled and surviving: individual mice with high metabolism

have

> > greater

> > > mitochondrial uncoupling and live longer.

> > > Aging Cell. 2004 Jun;3(3):87-95.

> > > PMID: 15153176

> > >

> > > Two theories of how energy metabolism should be associated with

> > longevity, both mediated via free-radical production, make

completely

> > contrary predictions. The 'rate of living-free-radical theory'

(Pearl,

> > 1928; Harman, 1956; Sohal, 2002) suggests a negative association,

the

> > 'uncoupling to survive' hypothesis (Brand, 2000) suggests the

> > correlation should be positive. Existing empirical data on this

issue

> > is contradictory and extremely confused (Rubner, 1908; Yan &

Sohal,

> > 2000; Ragland & Sohal, 1975; Daan et al., 1996; Wolf & Schmid-

Hempel,

> > 1989]. We sought associations between longevity and individual

> > variations in energy metabolism in a cohort of outbred mice. We

found

> > a positive association between metabolic intensity (kJ daily food

> > assimilation expressed as g/body mass) and lifespan, but no

> > relationships of lifespan to body mass, fat mass or lean body

mass.

> > Mice in the upper quartile of metabolic intensities had greater

> > resting oxygen consumption by 17% and lived 36%

> > > longer than mice in the lowest intensity quartile. Mitochondria

> > isolated from the skeletal muscle of mice in the upper quartile

had

> > higher proton conductance than mitochondria from mice from the

lowest

> > quartile. The higher conductance was caused by higher levels of

> > endogenous activators of proton leak through the adenine

nucleotide

> > translocase and uncoupling protein-3. Individuals with high

metabolism

> > were therefore more uncoupled, had greater resting and total daily

> > energy expenditures and survived longest - supporting

the 'uncoupling

> > to survive' hypothesis.

> > >

> >

> >

> >

> >

> >

> >

> > ---------------------------------

> > Looking for earth-friendly autos?

> > Browse Top Cars by " Green Rating " at Autos' Green Center.

> >

>