Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: wolram on 17/02/2006 22:13:34
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I have read a little on this subject, but i am not qualified to form
an oppinion.
A born optomist
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I assume you are talking about specific processes, not about general wear and tear. There is no machine that can be prevented from suffering from wear and tear in one way or another. One can protect against certain aspects of wear and tear, and delay the onset of total system failure, but one cannot prevent it from happening.
George.
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So if humans could live to 200,300 yrs, they would be in no phsical condition to do much.
A born optomist
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quote:
Originally posted by wolram
So if humans could live to 200,300 yrs, they would be in no phsical condition to do much.
Not quite what I said.
As far as I am aware, human design parameters are designed for a natural life span of about 40 years. We have pushed those parameters to about 70 years. No doubt we could push those parameters further. All I was saying was that one could not remove those parameters altogether.
That having been said, at least in recent centuries, most of out increased average life span has been achieved by a reduction in early mortality, and very little by an actual increase in maximum survivable age. There have always, in historic times, been individuals who survived to 80 years of age, it is simply that far more of them were dying in infancy and early adulthood. There has never been documented, outside the annals of mythology, an individual who has survived until 200 years of age.
It may well be (though I would not predict it as being inevitable) that we could some day push our life spans to about 400 years, and thus merely be reaching middle age on out 200th birthday, but that is not the same as stopping ageing.
George.
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Three score years and ten has been around for quite some time, so what's changed?
"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
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quote:
Originally posted by Andrew K Fletcher
Three score years and ten has been around for quite some time, so what's changed?
That has been true as far back as we have historic records – i.e. over that last few thousand years; but does not tell us what the life span was in pre-agricultural times.
As I said, what has changed over the historic era is that far more people are actually getting to live to three score years and ten, and far fewer dying within the first 5 of them.
George
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Paleolithic humans had a life span to about 40. This was usually because of hunting accidents, infections, or childbirth. Paleo's were much healthier than we are today, and if they had the technology and medicine we do, could easily have live to be over 100.
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You take some DNA...you change a little bit here and a little bit there....you tell it to stop deciding to fail to replicate and to continue to replicate efficiently..and there you have it ..immortality ...
Men are the same as women.... just inside out !!
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quote:
Originally posted by elegantlywasted
Paleolithic humans had a life span to about 40. This was usually because of hunting accidents, infections, or childbirth. Paleo's were much healthier than we are today, and if they had the technology and medicine we do, could easily have live to be over 100.
More to the point, the unhealthy one's didn't live long enough to reach adulthood.
George
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there werent unhealthy ones... heart disease, stroke, diabetes were not problems in that era. Wild game and naturally occuring fruits are incredibly healthy for you. It wasnt until the advent of agriculture did our health begin to decline, and now with over 50% of American's being overweight and non active im sure the life span will soon drop.
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quite obviously some one has found the elexir of life, otherwise how do you account for cliff(im still 15)richard.[:)]
RE-HAB IS FOR QUITTERS.
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quote:
Originally posted by elegantlywasted
there werent unhealthy ones... heart disease, stroke, diabetes were not problems in that era. Wild game and naturally occuring fruits are incredibly healthy for you. It wasnt until the advent of agriculture did our health begin to decline, and now with over 50% of American's being overweight and non active im sure the life span will soon drop.
But, for the most part, heart disease, stroke, diabetes are not problems for most people in our society who are younger than 40 years of age, and the few to whom it would be a childhood problem, simply would not have lived to adulthood in palaeolithic times anyway.
The issue of weight is probably less to do with diet in palaeolithic times, as to do with all the running around after game. The problem in modern times is that we have a life style closer to that of a blue whale than of a jaguar, and we have the fat levels to go with it.
George
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Another Someone, please take the time to read this article (it is a bit long) I'm sure you will find that the ramifications of lifestyles today do impact our health related problems. Even from a nutritional standpoint Paleolithic humans ate an extremley healthy diet. One that we can all learn something from.
This report is written by S. Boyd Eaton and Loren Cordain two of the leading experts in Paleolithic nutrition.
http://www.thepaleodiet.com/articles/Counter%20Arguments%20Paper.pdf
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About 20% of hunter-gatherers reach age 60 or beyond [6,7], but even in this age bracket, individuals from foraging and other technologically primitive cultures appear almost completely free from manifestations of most chronic degenerative diseases [8,9] (osteoweight, is an exception). Together, these observations strongly suggest that it is current Western lifestyle rather than age alone that promotes those “afflictions of affluence,” the prevention of which is a major goal of contemporary health promotion efforts.
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quote:
Originally posted by elegantlywasted
Another Someone, please take the time to read this article (it is a bit long) I'm sure you will find that the ramifications of lifestyles today do impact our health related problems. Even from a nutritional standpoint Paleolithic humans ate an extremley healthy diet. One that we can all learn something from.
This report is written by S. Boyd Eaton and Loren Cordain two of the leading experts in Paleolithic nutrition.
http://www.thepaleodiet.com/articles/Counter%20Arguments%20Paper.pdf
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About 20% of hunter-gatherers reach age 60 or beyond [6,7], but even in this age bracket, individuals from foraging and other technologically primitive cultures appear almost completely free from manifestations of most chronic degenerative diseases [8,9] (osteoweight, is an exception). Together, these observations strongly suggest that it is current Western lifestyle rather than age alone that promotes those “afflictions of affluence,” the prevention of which is a major goal of contemporary health promotion efforts.
Very interesting, but also, in my view, somewhat inaccurate.
Firstly, your comment above, that people in hunter gatherer communities who reach the age of 60 are less likely to chronic diseases – but my contention is that in such communities, such chronic diseases are more likely to have fatal outcomes, and thus fewer of those who survive will have such diseases, because those who have such diseases will not survive.
Secondly, as has been pointed out, one of the biggest differences between hunter-gatherer communities and modern communities is exposure to certain types of infection. Hunter-gatherer communities will be very highly subject to infections that cross species boundaries, since they will be in constant contact with other species, but will be much less susceptible to diseases that are species specific, since they will have less contact with such a wide range of other human beings. Inter=species diseases tend to be acute diseases, while many species specific diseases tend to be long term, often chronic (or at least with a long latency) diseases.
http://www.thepaleodiet.com/articles/Counter%20Arguments%20Paper.pdf
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This coin has another side, however. While chronic degenerative diseases generally produce mortality in later life, they begin much earlier, often in childhood. This allows comparison between age-matched younger members of industrial and technologically primitive societies. Biomarkers of developing abnormality such as obesity, rising blood pressure, nonobstructive coronary atherosclerosis, and insulin resistance are common among the former, but rare in the latter [3,4]. Measurements of muscular strength and aerobic power reveal similar discrepancies [5], again favoring individuals whose lives more closely resemble the ancestral pattern.
Do we know that there is true proportionality between the biomarkers and the subsequent chronic diseases?
There is a presumption that these biomarkers can of themselves be used as a sole predictor of chronic disease. This is very different from saying that they may have a contribution to play.
http://www.thepaleodiet.com/articles/Counter%20Arguments%20Paper.pdf
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Although technically imprecise, this article uses “life expectancy,” “longevity,” and similar expressions interchangeably to indicate the probable average number of years of life expected, at birth, for members of the entire population under consideration.
Life expectancy estimates for recently studied forager populations converge on a figure of about 40 years [6,7,10,11], and it seems reasonable to extrapolate a similar value for preagriculural, behaviourally modern Scone Agers. The adoption of farming and settled living only considered an advance for humanity, but the new conditions appear to have adversely affected longevity, precipitating a substantial decline to about 20 years [12]. Mortality profiles thereafter remained relatively stable (as late as 1667 average life expectancy n London was estimated to have been 18) [2] and it seems likely that from the Neolithic Revolution until the late 18th century, expectation of life in 'civilized' nations seldom or never exceeded 25 years Thereafter, technological breakthroughs in food production, manufacturing, transportation, trade, communications, and energy generation g rise to what economists call modem economic growth [13,14].
It clearly states earlier that it is inaccurate to confuse life expectancy with longevity, yet goes ahead and does just that.
Yes, life expectancy in pre-modern agricultural civilisation was poor, but the key question that matters for the point of view of our discussion is what was the life expectancy of those who reached late adulthood, or even more importantly, those who reached old age. Pre-modern agricultural societies had very high child mortality rates, which was compensated for by having very much more children; but none of this is relevant to a discussion on long term health in later years.
http://www.thepaleodiet.com/articles/Counter%20Arguments%20Paper.pdf
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If agriculture and “civilization” have significantly altered the human genome, groups like the Kalahari San, arctic Inuit, and Australian Aborigines, whose ancestors were hunter-gatherers until recent centuries, should differ, genetically, in some systematic, identifable way from Near Easterners, Chinese, and New Guineans, whose ancestors adopted farming millennia While there is genetic variation between different human populations, some of which affects disease susceptibility, little of this variation can be ascribed to the effects of cultural developments during the past ten millennia. (Lactose and gluten tolerance, as well genetically, from our Stone Age ancestors.
as several hemolytic anemias, are possible exceptions.) There has been ample time for important changes in the human gene pool since the Neolithic Revolution, but comparative genetic data provide compelling evidence against the contention that long exposure to agricultural and industrial circumstances has distanced us,
I would add our reduced jaw size and changes in dentition is another modern adaptation to diet.
Clearly, changes in skin colour, although an adaptation to changes in sunlight, also have implications for diet, since it effects the amount of vitamin D and folic acid that can be obtained from sun light.
I cannot see that anything I have seen in this, or anywhere else, support the assumption that other genetic changes have not taken place – at best, there can be the negative assertion that no-one has yet identified other changes.
http://www.thepaleodiet.com/articles/Counter%20Arguments%20Paper.pdf
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The answer is that differences between ancestral environments across time and space were minor compared with their essential similarities, especially when contrasted with human experience in the affluent present. Whether Stone Agers lived in the arctic or the tropics, vigorous physical exertion was essential; for foragers living 500,000 or 50,000 years ago food was derived from naturally occurring vegetation and wild game. Age at first pregnancy, nursing patterns, and birth intervals varied little among prehistoric hunter-gatherers but, in general, differed markedly from the reproductive experiences of most women in contemporary affluent nations[29]. If the social organization of recently foragers can be extrapolated into the past—which is studied probably valid at least back to the appearance of behaviourally modern humans—nomadic Stone Agers lived in small groups whose members knew each other intimately, not in megapolitan aggregations of strangers and casual acquaintances.
While I would agree with much of the above, but most of it has little to do with diet. If it is an argument that we should have more physical excursion, that would be fine, except that by his own admission, pre-modern agriculture required at least as much excursion as was applied by hunter-gatherer communities, and yet he regards pre-modern agricultural life as no more healthy than modern life.
If it is argument that women should have their first child soon after reaching puberty, and then have children at approximately 3 yearly intervals, it is not at all clear that this is his conclusion, although it is clearly implied in his logic.
Although he says that “food was derived from naturally occurring vegetation and wild game“, what he omits to say is that naturally occurring vegetation and wild game meant very different things to someone living on a pacific island, someone living in dense forest, and someone living in the Arctic tundra.
George
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I’ve heard aging is just mistakes when DNA is copied. If so to stop aging we would have to check each strand of DNA after the polymerases go through, right.
"Ideas are more powerful than guns. We would not let our enemies have guns, why should we let them have ideas." -Joseph Stalin
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Alright another someone (George is it?), I have my opinions you have yours, sound good?
-Meg
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Can ageing be stopped
I'm living proof[:)]
Michael
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Originally posted by elegantlywasted
Alright another someone (George is it?), I have my opinions you have yours, sound good?
-Meg
Indeed, I would not expect it otherwise.
George
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quote:
Originally posted by neilep
You take some DNA...you change a little bit here and a little bit there....you tell it to stop deciding to fail to replicate and to continue to replicate efficiently..and there you have it ..immortality ...
Men are the same as women.... just inside out !!
“Backward evolution” spawns ape-like people
Feb. 21, 2006
Special to World Science
An editor of a noted scientific journal says he has discovered a genetic defect that seems to set back the clock on human evolution by more than a million years.
Walking patterns of victims of Uner Tan syndrome. (Courtesy Uner Tan/ International Journal of Neuroscience)
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Its victims walk on all fours and mouth a primitive language, the scientist reported. He added that the syndrome may literally undo eons of evolution, and thus reflect with some accuracy what our ape-like ancestors were like.
The researcher, Uner Tan of Cukurova University Medical School in Adana, Turkey, has posted an online video clip of an affected woman walking on all fours, her face blurred.
The idea that evolution can run backward isn’t new; some scientists say there have been confirmed cases of it in animals. But it’s also a controversial subject, and considered hard to prove in any given case.
Tan, at any rate, argued that this could be a case of it, so the mutation—known to run in one Turkish family—might offer scientists an unprecedented glimpse into human origins.
“This syndrome interestingly exhibits prehuman features” and represents “possible backward evolution,” he wrote in a paper describing the condition. As such, it “can be considered a live model for human evolution.”
The paper appears in the March issue of the International Journal of Neuroscience, where Tan sits on the editorial board. He also named the condition after himself: Unertan syndrome.
http://www.world-science.net/exclusives/060221_unertanfrm.htm
[:D]Sorry Neil[:D]
"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"