Sep 25 2008

Calorie Restriction for Life Extension

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Comments: 87

There is a fairly direct correlation between scientific medicine and life expectancy, both historically and geographically. This makes sense – as we get better at preventing and treating diseases people will live longer. But the ultimate “disease” is aging itself. As we get older, our cells age, their DNA is damaged and the repair mechanisms are less effective. In short, our cells wear out.

Some researchers have therefore focused their efforts on discovering what, exactly, is happening to our cells as they age and can these processes be stopped or reversed. The motto of these researchers is “death in an engineering problem.” It is not inevitable – it is simply a challenge. Researcher Aubrey de Grey has been one of the most visible proponents of so-called “rejuvenation research.”

I have watched this research with an open mind but skeptical eye. Theoretically there does not have to be anything inevitable about aging. It is just another physical process. There is not theoretically reason why it should not be possible to intervene in whatever processes constitute aging.

However, I think aging will be a much tougher nut to crack than the rejuvenation enthusiasts imagine. Once we pick the low-hanging fruit, we are likely to find that some effects of aging are very difficult to address. Further, once we start trying to fix some of the effects of aging, only then will we discover what the true implications of such interventions are. There may be a host of downstream effects that then have to be addressed.

One of the current lines of research in life extension is calorie restriction. Mice who are fed a low-calorie diet (just enough to stay alive) live substantially longer (20-40%) than mice fed a more typical diet.  This is an impressive and reproducible effect. Some people, in fact, have decided to live with a calorie-restricted diet in order to reap the life-extension benefits seen by mice. Calorie restriction research has also gone beyond merely demonstrating an effect, towards looking at what the specific effects of calorie restriction are on cells and in specific diseases. Some research shows benefit, other research does not.

While the notion of calorie restriction to prolong life makes some sense – if a candle burns more slowly it will last longer – I have always had a problem extrapolating from mice to humans when it comes to life extension. The two primary reasons for my hesitance are: mice models of human disease are sometimes useful, but other times do not predict human responses; and mice only live months in the lab (a well-cared for mouse can live a few years), which makes it difficult to extrapolate to the 80 year life span of a human.

This latter fact has always been a real sticking point for me. It seems likely that the processes of aging that kill off a mouse in months would differ from those that take years in a human. Not necessarily in every way, but probably in some important ways. Looking through the literature I find that this is probably true – some metabolic factors turn out to be the same in humans and mice, while others differ.

A recent study looks at what at present is the likely primary mechanism by which calorie restriction extends life in mice – IGF-1. Insulin-like growth factor 1 is decreased by calorie restriction. Research also shows that if you knock out the gene for IGF-1 mice will live longer.  What the new study does is look at IGF-1 levels in humans on a calorie-restricted diet. They found no difference from normal controls. Therefore calorie restriction does not seem to lower IGF-1 levels in humans as it does in mice, and this may negate the longevity effect seen in mice.

But, there is more to this research. They did find that those on a low protein diet did have lower IGF-1 levels. And, when they had some of those on the low-calorie diet change to a lower protein diet their IGF-1 levels decreased. So perhaps it is low-protein and not low calorie that is the key (which, if true, throws a monkey wrench into the low-carb/high-protein diet craze).

What this research shows is that animal metabolism is a complex interwoven web and when you pull on one thread you cannot always predict all of the consequences. It also shows that while humans and mice are similar enough to make mice a useful model for research, there are differences and so mouse research is always considered preliminary and not definitive. It paves the way for human research, but not does replace it. Specifically, the question is whether or not mice are a good model of human aging, and I think there is good reason to conclude – probably not.

It is too soon to go on a protein restricted diet, and I would seriously reconsider a calorie-restricted diet if you think it will make you live longer. But this research is likely to teach us a great deal about human metabolism and the mechanisms of aging, and will also likely lead to specific recommendations for healthy living. But we are a long way from the elixir of life, despite the enthusiasm of the early adopters.

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87 responses so far

87 Responses to “Calorie Restriction for Life Extension”

  1. Fred Cunninghamon 25 Sep 2008 at 9:17 am

    At one point it was thought that a period of calorie restriction would have a lasting effect. I imagine that someone would have made a study of concentration camp survivors or similar group to see if there is an effect. Just wondering if anything has been published or maybe there are too many confounding factors.

  2. Johnon 25 Sep 2008 at 9:21 am

    As my partner is a vegetarian, we frequently have to put thought into making sure our diet contains good sources of protein. Eating low-protein meals not only fails to fill me up (making me more likely to snack), but also leaves me feeling tired. Even if a low-protein diet does work, I think I’d rather be happy and active than have an extra 20-40 years of lethargy. :D

  3. Perky Skepticon 25 Sep 2008 at 10:33 am

    Even if calorie-restriction does provide a longer life, I cannot imagine that the commensurate drop in quality of life would make up for it.

    Pass the creme brulee!

  4. jimon 25 Sep 2008 at 11:26 am

    Whilst I couldn’t imagine following a calorie restricted diet for a lifetime, restricting protien is more feasable, do we know how much makes a difference?

    it does get me thinking however that cultures with low protien intake should show a greater maximum lifespan, or that the worlds oldest human being should be a vegetarian?

  5. daedalus2uon 25 Sep 2008 at 12:28 pm

    Bruce Ames has done some recent work that indicates that some of the “damage” of aging is due to deficiencies in some essential nutrients. I went to a talk he presented a month ago, and his premise is that physiology does what he calls “triage”, that is that when there is not enough of a certain nutrient, the body directs it to the most important near term use and longer term less important uses don’t get enough.

    He used an example of folate, where low folate causes more frequent substitution of the incorrect base in DNA during DNA replication. Later DNA repair enzymes can fix it, but if there are too many substitutions too close together, it ends up causing a double strand break which is not repairable.

    Depending on what type of cell that happens in, and where the break is, it may be important or not.

    The RDAs of nutrients was determined in a pretty ad hoc manner, find out what level causes an acute deficiency disease in healthy young individuals then add a safety factor. Not terribly evidence based if you are interested in what the effect is on health in 20, 50, or 100 years.

  6. James Foxon 25 Sep 2008 at 1:20 pm

    It seems logical to assume that one bad case of the flu, infection, serious accidental injury or an otherwise treatable cancer is more likely to be a death sentence for a calorie restricted (under fed) inordinately thin older person.

  7. rc_mooreon 25 Sep 2008 at 2:55 pm

    …Bruce Ames has done some recent work that indicates that some of the “damage” of aging is due to deficiencies in some essential nutrient…

    It always sounds good when people say major health benefits can be gained from simple changes is diet. But there is a big difference in a nutrient, that lacking, causes illness, and a nutrient that significantly improves the health of an otherwise healthy person.

    The snake oil salesmen are endemic is this area, and many have MD or Ph.d after their name. We can watch this research with interest, but I prefer the biggest bang for the buck — put the money into cures for disease that are cost effective and help the planet as a whole. Everyone deserves a normal, healthy lifespan.

    On a different note, I for one shudder at the prospect of a planet of 300 year old people, with the same level of education and intelligence we have today. No research has suggested starvation diets make you a better person.

  8. daedalus2uon 25 Sep 2008 at 3:59 pm

    rc, I wasn’t clear in my explanation. The Ames’s hypothesis is that deficiencies in certain nutrients cause damage that causes difficulty in the future, maybe 20 or 40 or more years in the future. It isn’t snake oil, but it is very difficult science to actually do because it takes so long.

    He doesn’t suggest that what he is talking about will improve the health of an otherwise healthy person. What he hypothesizes is that it will slow the decline in health of an otherwise healthy person.

    His hypothesis does make a lot of sense, and it parallels much of my thinking which is related to nitric oxide. Nitric oxide regulates the ATP level, and cells do “triage” ATP metabolism by shutting things off when there isn’t enough ATP (that is what ischemic preconditioning is). Repeated bouts of ischemic preconditioning do cause increased wear and tear on cells and increase the incidence of many degenerative diseases.

  9. sonicon 25 Sep 2008 at 4:27 pm

    Is the goal a longer life?
    I have had people beg me to end their lives.
    We must be clear what it is we are shooting for- the statistic “number of years alive” is not a correct statement of something we need to maximize.
    Be careful what you wish for…

  10. pecon 25 Sep 2008 at 8:36 pm

    “There is a fairly direct correlation between scientific medicine and life expectancy, both historically and geographically. This makes sense – as we get better at preventing and treating diseases people will live longer.”

    That is such a misleading statement. You know that most of the increase in life expectancy results from dramatic decreases in infant mortality, and from antibiotics. Infant mortality can’t be reduced to less than zero, and we already have benefited from antibiotics. Life expectancy is NOT increasing very much because of advances in treating anything aside from bacterial infections and diseases that used to cause infants and children to die.
    Other major causes of increasing life expectancy, such as decreasing cigarette smoking and better sanitation and nutrition, are unrelated to medical advances.
    You know this, and other blog authors at this site or at sciencebasedmedicine have stated it directly not long ago. But that does not prevent you from implying that ongoing medical progress is responsible for steadily increasing life spans.

    “But the ultimate “disease” is aging itself.”

    Ridiculous. If people find a way to stop dying — which fortunately won’t ever happen — they will have to also stop reproducing. Aging is not a disease; it is programmed into organisms to prevent over-population, and to allow reproduction and evolution.

  11. Roy Nileson 25 Sep 2008 at 10:09 pm

    Pec,
    Actually my understanding (such as it is) has been that aging is not programmed into organisms to prevent over-population. What is programmed, if anything related to life expectancy is concerned, is enough resistance to the wear and tear of living to allow time for the organism to successfully replicate itself. After that, death occurs mainly after the various parts wear out sufficiently to cause resistance to be, as some would say, futile.

  12. nwtk2007on 25 Sep 2008 at 10:45 pm

    If that were true Roy, there would not be uniform, or close to it, life expectancies within measurable and recognizable ranges for specific species.

    I think most biologists would say and most references would suggest that aging is programed into organisms.

    There is wear and tear and the need to stay alive to reproduce is, indeed, there, but the need to reproduce is seen inherently in the organisms ability to repair the damage.

    When damage occurs to an organism, the repair process is such that, at least in mammals, to repair sufficiently to be able to gain sustenance and survive to reproduce. Case in point, scar tissue and inflammation. Not repair to as good as new, but repair to survivablility.

    Even in culture, cells will limit themselves to specific numbers of divisions, exceptions being cancer cells. There are some exceptions here also, but many were ruled out as being contaminated by cancer cells. And there are variable ranges of this as well so one cannot delineate by setting examples of just a few cell types, or above, with specific species or organisms.

  13. Roy Nileson 25 Sep 2008 at 11:20 pm

    ntwk,
    Actually you have pretty much made my point, except that you seem, like pec, to have the programming aspect of things bass-ackwards.
    The uniformity is due more to the adaptation process of the particular organism in its particular niche in a particular environment with a particular amount of competition for its survival. What appears to be a program for setting an upper limit on the length of its whole life is more likely the inevitable consequence of programming for the minimum life span that the species would need for individual members to collectively produce enough offspring to replenish losses due to other than simply reaching a specific age within that species.

    If the cells you cite have set limits, it would be more because that’s how long they have “need” to live rather than that there is any need foreseen of the benefits of dying for its own sake. In other words, everything that looks like it is the result of programming is not for that reason alone likely to be such in actuality.

  14. nwtk2007on 25 Sep 2008 at 11:34 pm

    You’re not familiar with cells in culture. I won’t go there.

    Your idea about environment is cancelled out when looking at domesticated animals and those same ones in the wild.

    Either way you look at it, it is still programed in. Whether programmed for minimum life span or maximum, makes no difference.

  15. Roy Nileson 25 Sep 2008 at 11:54 pm

    nwtk,
    What I’m familiar with is the writing of George C Williams, Plan and Purpose in Nature, and more to the point, as cell cultures are concerned, the information presented by Carl Zimmer in the book, Microcosm. In particular, look on page 95 where reference is made to the aging process of microbes.

    And of course, programming for minimum as opposed to maximum life-span makes a hell of a difference when you’re interested in the the nature and mechanism of evolution in general and of the programming functions in particular.

  16. Roy Nileson 26 Sep 2008 at 4:16 am

    nwtk, check this commentary out while you’re at it:
    http://www.evolutionary-philosophy.net/aging.html

  17. Calli Arcaleon 26 Sep 2008 at 1:07 pm

    When asking the interesting question of whether aging is preprogrammed or merely the result of stuff wearing out, it may be useful to look at patients with progeria. They usually die of old age before even getting into high school. It’s a rare condition, but interesting, because they suffer from geriatric diseases despite their youth, and age at an astonishing rate. They even get wrinkly, and most die of heart attacks due to atherosclerosis. But they don’t get things like Alzheimers, and they don’t suffer cataracts or osteoporosis. It seems that aging is too complex to summarize as “wearing out”, and some elements may be genetically programmed (such as baldness, gray hair, wrinkled skin, and menopause) while others are merely our bodies succumbing to the forces around them.

  18. Roy Nileson 26 Sep 2008 at 1:50 pm

    Calli,
    pec had said, with his usual take on nature’s alleged purposes, that: “Aging is not a disease; it is programmed into organisms to prevent over-population, and to allow reproduction and evolution.”

    He was also saying this in the context of life-expectancy, and my point was that such programming was simply not the case – and the following expands on the wearing out process much better than I could:
    http://www.evolutionary-philosophy.net/aging.html

    Baldness, grey hair, menopause, cannot (in my view) be held to be part of the programming that allegedly results in a pre-planned death of the individual in a species. They may in fact be ways we react to the deterioration of various parts and functions, or to their cessation when no longer needed.
    And don’t ask me why, for example, salmon suddenly deteriorate after spawning, because that certainly appears to be part of their programming. But I strongly suspect this representation of nature’s purpose is deceiving as well.

  19. Roy Nileson 26 Sep 2008 at 3:17 pm

    Note that nwtk2007 had also remarked that: “Your idea about environment is cancelled out when looking at domesticated animals and those same ones in the wild.”

    I just can’t resist adding this quote from the previously cited commentary:

    “Researchers have observed that animals living in the harsh conditions of the wild survive for only a short period of time compared to those living in the protected conditions of captivity. For example, nine out of ten mice living in the wild will be dead before the age of ten months, whereas mice raised in captivity have an average lifespan of twenty-four months. Very few individuals of any species living in the wild survive long enough for there to be any evolutionary pressure to set an age limit.

    Studies have also shown that when animals grow old in protected conditions, there is no particular age at which they begin to die off more quickly. In fact, for many animals, the rate of death starts to slow down in extreme old age, which is the opposite of what would be expected if death was programmed.”

  20. daedalus2uon 26 Sep 2008 at 5:41 pm

    I think there is much confusion over what “programmed” means in the context of aging. Much of this confusion comes from anthropomorphizing how non-human organisms behave, and how cells behave and attributing that behavior to human-like motivations such as altruism.

    Organisms and cells are not “programmed” in the same sense that computers are programmed, to follow an algorithm. There is no overall “goal” other than survival and reproduction. What ever specific developmental path an organism proceeds down during its lifespan is an emergent property of its genes and the environment it developed in.

    A trait that causes cell aging and death may have important survival features. For example the eventual senescence and death of dividing cells as their telomeres decrease in length is likely an important “feature” preventing cancer cells from dividing uncontrollably. Similar mechanisms of degeneration may have the same function but not be so explicitly observable. There may be limits to DNA repair mechanisms, not to cause programmed death of organisms per se, but so that individual cells suffer DNA damage that cause individual cell death rather than repair that damage and lead to cancer and death of the entire organism. Death of cells in an organ that can be replaced via stem cells or not replaced and the organ allowed to shrink is much better than death of the organism due to uncontrolled replication of a tumor.

    There is metabolic “overhead” associated with keeping DNA in an undamaged form. It takes ATP to repair it, ATP to prevent formation of free radicals that damage it, ATP to fix other things that are damaged. ATP used for “overhead” and maintenance is ATP that can’t be used for reproduction.

    A way to look at a potential evolutionary advantage of a longer life would be to consider the evolutionary value of producing a single clone (the evolutionary equivalent of extending lifespan) vs producing multiple offspring that share half the genome. Most organisms have multiple offspring, sometimes hundreds or thousands or even more. The metabolic cost of producing many small offspring that are free living is tiny compared to the cost of producing a single full size adult. It makes no evolutionary sense to spend resources to make a single adult clone when those same resources could make hundreds of half clones.

    I think that the rejuvenation advocates such as Aubrey de Grey are hopelessly naïve as to the degree of difficulty of what they are proposing. Physiology is more complicated than they appreciate by many orders of magnitude (my guess is at least 6 orders of magnitude, but such guesses are extremely imprecise, it could easily be 10 or more, it can’t be as low as 4). We don’t “fully understand” the function of any single protein in human physiology and how that protein interacts with all others. There are ~10^5 proteins in human physiology. Understanding interactions between proteins goes as the number factorial. Until we do understand physiology, we don’t know how much there is to understand. There is great potential for the arrogance of ignorance to lead people to believe they know more than they actually do.

    While there is no theoretical limit to lifespan, implementing changes to physiology to implement an indefinite lifespan is something we don’t have the foggiest clue of how to do when starting from scratch, let alone along a path to implement it onto an already living organism without changing that organism’s memories. If the guess of 6 orders of magnitude is correct, then to get to where we do understand physiology enough to do these things we need a million times more effort than has already gone into understanding physiology. That is roughly a million times more labor than has already gone into studying physiology. That is a lot of research.

    The main difficulty in understanding physiology is that biological systems did not evolved to be modular and easy to understand. They have evolved simply to work, how they work is unimportant for them to work, but is critically important for understanding how to hack into them and make them work many orders of magnitude better than they ever have worked before.

    How easy would it be to hack into the hardware of a 286 and turn it into the latest Pentium? While it is running and without having it crash? A trivial exercise compared to what the rejuvenation enthusiasts are trying to do. Biological systems only seem simple because we are ignorant of the details.

  21. Roy Nileson 26 Sep 2008 at 6:44 pm

    http://www.instantrimshot.com/

  22. pecon 26 Sep 2008 at 7:45 pm

    “nine out of ten mice living in the wild will be dead before the age of ten months, whereas mice raised in captivity have an average lifespan of twenty-four months. Very few individuals of any species living in the wild survive long enough for there to be any evolutionary pressure to set an age limit.”

    Infant mortality is generally very high in nature, for all species. This brings the average life span way down and leads to the misconception that wild animals are less healthy than domesticated animals. Infant mortality is one of nature’s primary mechanisms for preserving the integrity and health of species.

    So we can’t draw any conclusion based on average life span.

    Aging and death is universal for all sexually-reproducing species. And every species has its own typical life span. Therefore, aging and death are at least partly genetically determined.

  23. Roy Nileson 26 Sep 2008 at 8:40 pm

    Yes, but not for the purpose that you gave, which was “to prevent over-population, and to allow reproduction and evolution.”

    Deaths of such individual biological organisms as humans (and animals in general, etc.) are not the goal of purposeful programming, either to allow for reproduction or limit population growth.

    You might say that the effect that death has had on evolution, or contributed to evolution, was to signal the trial and error process that it needed to try again. The tree of life itself has never stopped growing. If it is programmed to do anything, that thing is to not die.

  24. nwtk2007on 26 Sep 2008 at 9:27 pm

    That fact that there are cell lines that have, essentially, immortality, shows that wear and tear is not the essence of aging. It is not limited by DNA repair or free radical damage, etc. This is fact.

    Also, as to life expectancy, comparing the wild to the domestic, one in a harsh environment and the other in a “less wear and tear” environment, it has been shown repeatedly that without the harsh environment, the life of the individuals is not greater than the longest lived individuals in the wild, harsh environment.

    In terms of evolution, it must be remembered that individuals do not evolve, only populations. Also, within populations, without death, there is no room for change and thus death is and has to be a mechanism of evolution and therefore must be a part of the population, in some form or fashion programmed, with variations within ranges due, simply, to variable combinations of genes and changing environmental conditions.

  25. Roy Nileson 26 Sep 2008 at 9:43 pm

    nwtk: Horseshit. Consequences cannot be assumed to coincide with the goals of a programmer. I don’t think you have the slightest grasp of how evolution creates programs, but it’s certainly not a goal oriented process.

  26. nwtk2007on 26 Sep 2008 at 11:14 pm

    Horse$hit, my a$$,

    I would not begin to presume that there is a programmer.

    Not in the least.

    It is has simply been selected for. The aging and death of individuals in populations.

    There is no “creation” of “programs” in evolution. And there is no implied “goal” oriented process either.

  27. Roy Nileson 26 Sep 2008 at 11:33 pm

    nwtk: Death is a concept that exists with sentient beings – to have it selected for in a population (to use your own word here) would be of no more significance to the evolutionary process than selecting for the elimination of excessive fur on a Neanderthal. So you don’t understand the process of selection any more than you presumed to understand adaptation.

    There are no creators of programs in evolution, but they are nevertheless created by the process. But it’s only those like pec and yourself that imply there’s a goal involved.

    Every time you shoot from the hip, you miss so badly that there’s little doubt left that you have no business claiming to teach science, or at least to do so with any degree of competence.

  28. nwtk2007on 26 Sep 2008 at 11:53 pm

    Still trying to insult.

    What have I said that implies that there is a “goal” in evolution?

    Obviously death would not be significant to the evolutionary process, unless it enhanced the survivability of the genes in the individuals of the population?

    That is the point. Aging and death other than by violent means, has been selected for and thus is “programmed” into the individuals of the population. Even death by violent means affects the sift in the gene pools, through selection of behavioral preferences and development of instincts, which ultimately, are determined by genetics.

    Outside of philosophical dogma, what is your point?

  29. Roy Nileson 27 Sep 2008 at 1:19 am

    My point is that I can and have cited credible sources that support my views and you cannot cite any but your own alleged status as a science teacher.

    Take this sentence for example:
    “Even death by violent means affects the sift in the gene pools, through selection of behavioral preferences and development of instincts, which ultimately, are determined by genetics.”

    That’s so much patched together drivel – sound without even fury or significance.

  30. pecon 27 Sep 2008 at 7:12 am

    Aging and death are obviously programmed. Whether there is a programmer is a philosophical question beyond our pay grade. But the fact of aging and death is a big problem for those of you who belligerently and self-righteously insist that evolution cannot be goal-directly or purposeful.

  31. pecon 27 Sep 2008 at 7:14 am

    typed: goal-directly
    meant: goal-directed

  32. nwtk2007on 27 Sep 2008 at 8:27 am

    What I am saying is that even their behavior and instincts are controlled by genetics and evolutionary process, which can effect longevity, by effecting their ability to avoid a violent death at the hands of predators, etc.

    In other words all aspects of a creatures longevity are controlled by genetics and evolutionary changes, thus, essentially programed.

    This is common knowledge and doesn’t need reference, especially philosophical reference.

    And your doubting my being an “alleged science teacher” is, if anything, cute but ineffective in explaining your position.

  33. Roy Nileson 27 Sep 2008 at 12:44 pm

    nwtk, it’s not my position that needs explaining, as it is one held by prominent evolutionary biologists, who, as a matter of fact, owe quite a bit to evolutionary philosophers, the most prominent of which was Charles Darwin.

    ALL aspects of a creatures longevity are NOT genetically programmed. Daedulus2u, a respected contributor here, made that abundantly clear earlier.

    Citing common knowledge as a reference is something a chiropractor might consider adequate, but not a bona-fide science instructor.

    ****

    pec, although you have a slightly better grasp of basic science than nwtk, you are still a believer in a purposeful force in nature, which is a philosophical position with no scientific support.

    My suggestion to you two birds is that you find some solace by talking amongst yourselves.

  34. Fifion 27 Sep 2008 at 12:57 pm

    Genetic expression is also influenced by environment so to say that “all aspects of a creatures longevity are controlled by genetics and evolutionary changes, thus, essentially programed” is just silly. A recent example would be some of the work on fruit flies exploring longevity.

    As Roy Niles points out, this is another example of why its problematic to have people who believe in and promote pseudoscience (and who want to claim their pseudoscience is science or “alternative” science, and have a vested financial interest in doing so because they make a living from pseudoscience) make for problematic science teachers and are part of the problem rather than contributing to a solution.

  35. daedalus2uon 27 Sep 2008 at 1:05 pm

    In “the wild”, there is no death other than by violent means, by starvation or by infection. When an organism becomes so debilitated that it can’t escape from a predator, it becomes a predator’s meal. When it becomes so debilitated it can’t get enough food it starves, when its immune system becomes so debilitated it succumbs to infection. If there are essentially no instances of organisms dying due to other means, there is no evolutionary pressure to evolve pathways to cope with those instances that never happen.

    If death were somehow “programmed”, then populations wouldn’t crash catastrophically (as they are observed to do). If death were programmed, deaths due to that programmed mechanism would be obvious and unrelated to any type of degeneration in any organ system. Those programmed deaths would increase as a fraction of deaths as organisms age. This is simply not observed.

    If there were some sort of programmed death which evolved to increase reproductive success of descendents, we would expect people with large numbers of descendents to have shorter lives than people with few or zero, and for them to die via this programmed death response. This is not observed.

    There are plenty of open niches available to organisms. Members of an organism’s species don’t need to die to free up resources for descendents, members of another species can die to free up resources. That is what predators do all the time; they kill another organism and take the resources it was using.

    There are plenty of physiological responses that can lead to death, anaphylaxis for example. It is wrong to think of anaphylaxis any sort of “programmed death”, even though anaphylaxis is programmed and it does cause death. There are many similar physiological responses. The organism tries to respond to a need, devotes resources to that need, and if the organism has insufficient resources to carry out that response successfully then the organism dies.

    As a cell’s DNA degrades over time, its ability to successfully initiate and carry out what ever physiological response it needs to invoke is reduced. As cells die, the remaining organs have less ability to do the same thing and atrophy. As organs atrophy the organism has less ability to do the same thing and when the final straw is reached, the organism dies.

    That organisms eventually senesce and die may give the illusion of programmed death, but that is an illusion caused by faulty thinking in the observer. Organisms can only stay alive if there are metabolic pathways that cause it to do so. If/when those metabolic pathways fail, the only outcome possible is organism death. Since there are no processes that provide arbitrary and unlimited repair capacity to cells, eventually those cells must die as the pathways keeping the cells alive degrade and eventually fail.

    Gravity makes objects fall. Objects are not programmed to fall. There is nothing that one can do to change the “programming” that makes objects fall. Thinking of the property of objects falling as something that is programmed and which can be altered by changing the programming is faulty thinking.

  36. nwtk2007on 27 Sep 2008 at 2:46 pm

    To say that aging is not related to genetics and that there is no inheritable characteristic that is involved in determining the longevity of the organism is very simplistic.

    I would also point out that populations, in theory, could be immortal outside of the deaths as mentioned by daedulus, but they aren’t.

    Assuming that DNA degrades over time without some set mechanism to promote it is a violation of what is seen. Reproductive individuals produce essentially clean and un-degraded DNA at every reproductive cycle and thus individuals are born with what you appear to be calling, un-degraded DNA. If DNA degrades as you say and the individual ages, then the DNA within the gametes would also be degraded and the population would die out and life would end as we know it.

    Certainly there are examples of decreased longevity not related to some aspect of genetic control, but even those can be seen as under genetic influence to some extent.

    Even the rate of DNA degradation is genetically determined when present and there are genes which enhance and others that oppose the repair mechanisms when they are present.

    The complexities of aging in multicellular individuals are such that one cannot say for certain that “programming” is present or absent. To some degree it absolutely is and in other instances it’s effect is canceled out by the huge number of factors.

  37. Roy Nileson 27 Sep 2008 at 3:06 pm

    “To say that aging is not related to genetics and that there is no inheritable characteristic that is involved in determining the longevity of the organism is very simplistic.”

    It would be if anybody here had actually said that. Only a simpleton would infer that they had.

  38. nwtk2007on 27 Sep 2008 at 3:13 pm

    Only a self absorbed snob would imply that it hasn’t been inferred.

  39. nwtk2007on 27 Sep 2008 at 3:15 pm

    And only a defensive, biased, “know it all”, self acclaimed philosopher would think that I was implying that someone had actually said that.

  40. Roy Nileson 27 Sep 2008 at 3:26 pm

    Spoken like a true simpleton. Which I understand IS a programmable place in the hierarchies of biological systems.

  41. Roy Nileson 27 Sep 2008 at 3:44 pm

    I’m also informed that the fact that simpletons were created to be the most expendable has been misinterpreted (often by those very simpletons) as a form of programmable life expectancy.

  42. Fifion 27 Sep 2008 at 4:38 pm

    nwtk – “To say that aging is not related to genetics and that there is no inheritable characteristic that is involved in determining the longevity of the organism is very simplistic.”

    Who said this?

    nwtk said – “all aspects of a creatures longevity are controlled by genetics and evolutionary changes, thus, essentially programed”

    then nwtk waffles and contradicts himself – “The complexities of aging in multicellular individuals are such that one cannot say for certain that “programming” is present or absent. To some degree it absolutely is and in other instances it’s effect is canceled out by the huge number of factors.”

    Clearly nwtk lacks even a basic understanding of how genes are expressed and nature/nurture – this isn’t something one needs to be a science teacher to understand, most people have at least a rudimentary understanding that their actions and environment influence genetic expression in terms of cancer and disease. As I mentioned, some of the current issues being discussed regarding research on longevity in fruit flies are directly about the influence of environment and longevity. There’s also been some interesting research on longevity and calorie restriction in rats and how it and if it relates to humans that’s just come out.

  43. daedalus2uon 27 Sep 2008 at 4:42 pm

    nwtk, No one has said there is no genetic component to the rate of aging. Obviously there is because the “only” difference between mice and humans is their genetics and mice and humans have very different life spans. There is a gigantic difference between genes having an effect on the rate of aging and saying that aging is programmed by genetics. If you are unable to appreciate that difference, there isn’t much use in trying to have a conversation with you.

    It is not an assumption that DNA degrades. It is extremely well known that there are mechanisms for DNA degradation, background ionizing radiation damages DNA, so do free radicals that are an inescapable part of metabolism.

    It is not correct that reproducing individuals produce only clean and undegraded DNA in their gametes. Only DNA that is relatively undegraded has sufficiently fidelity to grow into a new individual, but lot of gametes don’t grow into new individuals because their DNA is degraded.

    Gametes may have DNA that is less degraded that the DNA in somatic cells. There is nothing to suggest that that degradation is zero. Somatic cells are much more resistant to DNA damage than are gametes because somatic cells don’t need to express every single bit of DNA that is in the genome. Gametes essentially do need to express everything because the DNA from those gametes will be replicated into all the different somatic cells that makeup the individual that will grow from those gametes.

    There is no evidence that there is programming of aging and death of organisms. Organisms do not behave as if there was a mechanism for programmed organism death, there is no plausible mechanism by which programmed organism death could occur, there is no plausible mechanism by which programmed organism death could originate, there is no plausible mechanism by which programmed organism death would be heritable and stable in a population. There is no plausible mechanism by which programmed organism death would become a universal trait in a population. There are many reasons why programmed organism death would not occur.

    Programmed organism death is “possible” only in so far that it is not impossible. It is “possible” in the same sense that intelligent design is “possible”. Both require an essentially omnipotent intelligent designer to design and poof into existence essentially complete populations of organisms with gene pools precisely as designed. Not something that is impossible, only something for which there is no evidence.

  44. Dan Royon 27 Sep 2008 at 5:16 pm

    Geek fight, geek fight!

  45. pecon 27 Sep 2008 at 8:34 pm

    “you are still a believer in a purposeful force in nature, which is a philosophical position with no scientific support.”

    There is no scientific support for either purposefulness or purposelessness in nature. It is a philosophical question, and would require a precise definition of the concept “purpose,” which is inherently vague and ambiguous.

    Since there is no scientific support for either side of this question we can agree to disagree. I do not feel it’s unscientific to notice when something seems purposeful. The scientific method does not require us to deny purpose in nature.

  46. pecon 27 Sep 2008 at 8:41 pm

    daedalus2u,

    Why does each species have a typical maximum life span? If you exclude cases of premature death, variations in life span within a species would be quite small. How do you explain that, if you’re so sure maximum life span isn’t genetically programmed?

  47. Roy Nileson 27 Sep 2008 at 9:05 pm

    pec,
    Agreed that we are not required to deny purpose in nature, and certainly we find it in life forms. And we can, in my view, presume other purposeful forms exist in the universe. But we should not give preference to any postulation that ascribes intent to such a force as relevant to the workings of nature in our particular corner of the universe.
    We should not therefor postulate that the evolutionary process is goal oriented, which we would be doing if we mistook what seemed purposeful for being the result of some natural version of intention.

    This of course becomes a complicated exercise when it is necessary to sort out the effects that purposeful life forms have on their own evolutionary development. We should know, for example, that we wouldn’t have instincts if this form of purpose was not involved.

  48. nwtk2007on 27 Sep 2008 at 9:05 pm

    I have to agree with Pec here. And I think the bias of posters here are intent in nothing more than winning an argument with a pseudoscience promoter (not) and a science teacher which they are jealous of and cannot match the “contributions to science education” of.

    As yet, I have not heard of any of FiFi’s or Roy Niles contribution to science ed or anything even remotely related to medicine in general. I have taught science since 1978 and have the successful students to show for it. What have you done?

    And daedulus, being the “researcher” that you appear to be, albeit, engrossed in NO chemistry, I would think that you could at least speak reasonably about the DNA degradation issue.

    DNA and genes, to put it simply, have the ability to continue on adinfinum, as demonstrated by the continuation of life, despite the damage from free radials, radiation, etc. It simply happens. There are also ways that have evolved to deal with damage and the repair thereof. It is even redundant in it’s expression and has numerous mechanisms for dealing with it.

    DNA and molecular genetics might be beyond many of you, but to deny what you see or at least should know, is scientific heresy. Coming from the “scientific elite” here, I find it both humerous and laughable.

    To put it simply, your pants are down.

    Now if you are willing to admit that there are many factors influencing aging, including genes that are specific to the aging of an individual, then I am willing to entertain your insulting comments.

    Otherwise, I will continue to use you as examples of what science education is not meant to produce. I have a great audience and they enjoy your biased and insulting lunacy.

  49. Roy Nileson 27 Sep 2008 at 9:16 pm

    nwtk: If you had something to show, you have avoided every opportunity offered to show it.
    And any ignoramus can find an appreciative audience of fellow loonies.

  50. nwtk2007on 27 Sep 2008 at 9:33 pm

    As I have said, to those of us in the field. it is common knowledge.

    You want I should give evidence of water’s formula also?

    Take it leave it, makes no never mind to me.

  51. Roy Nileson 27 Sep 2008 at 9:56 pm

    Would that be the water that retains a memory? Or the version with the structure that reflects our consciousness?

  52. nwtk2007on 28 Sep 2008 at 12:24 am

    Homeopathist’s think water has memory, at least the purists do.

    I just think you are drunk.

  53. Roy Nileson 28 Sep 2008 at 12:45 am

    No, just trying to establish the parameters that measure the extent of your ignorance.

  54. nwtk2007on 28 Sep 2008 at 12:57 am

    Define the parameters you lush.

  55. Roy Nileson 28 Sep 2008 at 1:01 am

    Oh, and since you asked, my contribution to science involved many years working with the Atomic Energy Commission during the cold war and with NASA when the astronaut program was new.

  56. Roy Nileson 28 Sep 2008 at 1:10 am

    Parameters are measurable factors used to establish boundaries. The common reference to “defining the parameters” is a form of California speak, that was copied by Texans, and the use of which helps to establish the degree to which teaching standards have declined in both jurisdictions.

  57. nwtk2007on 28 Sep 2008 at 1:13 am

    Define them, as they pertain to as you say “the extent of ignorance”. Duh!

    And your contribution to science education?

  58. Roy Nileson 28 Sep 2008 at 1:20 am

    Well. we’ve acquired data here that points to the uppermost level of your cognitive abilities, which correlates remarkably well with observable ignorance, all other things being somewhat equal. Now data is being sought to establish how dumb you really are.

    My contribution to science education has been to try to undo the damage that people like you would have done to their students, had you actually been a science teacher.

  59. nwtk2007on 28 Sep 2008 at 1:42 am

    Roy Niles – “My contribution to science education has been to try to undo the damage that people like you would have done to their students,”

    In other words, none. You have made NO contribution to anything science education related.

    I thought so. All else is is hot air.

    Good night el “done nothing”.

  60. Steve Pageon 28 Sep 2008 at 5:00 am

    *fetches popcorn*

  61. pecon 28 Sep 2008 at 8:23 am

    nwtk2007,

    This blog is written by and for atheists/materialists and its main purpose is to fight against alternative science and medicine. It is associated with influential political organizations, such as JREF.

    Anyone who disagrees with any aspect of their ideology is insulted and called an idiot. They are absolutely certain their ideology is absolutely correct, and they are not interested in logical or scientific debate. My comments were censored and banned because I try to debate logically and provide scientific evidence.

    Just ignore the insults, and realize they call you stupid and ignorant only because they have no better way to defend their ideology.

  62. daedalus2uon 28 Sep 2008 at 8:55 am

    pec, if death was “programmed”, the cause of death via that “program” would be the same. If there was one type of programmed death, there would be no evolutionary need for another type of programmed death, any evolutionary change would occur on the control system regulating that already existing cause of death, not in generating a new type of programmed death requiring a separate control system.

    In other words, if an evolved system works perfectly, there is no evolutionary pressure to make it work better. Any system that caused programmed death would (if invoked) be 100% effective. Dead is dead and is irreversible. Any evolutionary pressure would be on optimizing the regulation of what triggers and regulates that death, not on the death process. If there is one programmed death pathway that has provided sufficient evolutionary benefit for it to have evolved, can another death pathway evolve in parallel to be redundant? No, because it takes many changes to many pathways to make a new programmed death mechanism and make it work appropriately. It would be much simpler to evolve changes in the regulation of the already existing programmed death pathway to make it work better. It is inconceivable that a newly evolving programmed death pathway would be sufficiently superior to an already existing already evolved pathway to evolve separately. The one that works “better” would be the only one selected for.

    Since there can’t be two or more programmed death mechanisms, is there at least one? Well, if so, which one is it. If we look at death rates

    http://www.ncbi.nlm.nih.gov/pubmed/18512336

    If we look at Table 9. Death rates by age and age-adjusted death rates for the 15 leading causes of death in 2005: United States, 1999–2005. We see that for most diseases the death rates have declined for each age group in the past 7 years. If a certain type of death were “programmed” to occur, I think you would agree that it would be beyond the power of feeble materialistic medicine to prevent it by physical interventions. If modern medicine can reduce the death rate from a certain mechanism, that mechanism cannot be the programmed death mechanism. The diseases which exhibited an increased death rate were Alzheimer’s, Parkinson’s, essential hypertension and kidney disease. Could any of these be the “programmed death”?

    If we look at table B, we see that Alzheimer’s causes 2.9% of deaths. Can something that causes 2.9% of deaths be the programmed death mechanism? No, 2.9% is too small a percentage to be a significant cause of death.

    Figure 5 shows the same thing in graphical form going back to 1958. Gradual decline in the incidence of most diseases with the exception of Alzheimer’s. Deaths due to Alzheimer’s go off scale low in 1980 at ~3 orders of magnitude rarer than heart disease, cancer and cerebrovascular disease. In the absence of modern medicine, modern sanitation, modern food supplies, modern heating systems, etc. deaths due to things other than Alzheimer’s in old age would be higher. In “the wild” which is where humans lived during evolutionary time, deaths due to Alzheimer’s would be exceedingly rare. Is there any mechanism where such a rare occurrence would so improve the survival of an individual’s descendents that it would be highly selected for? No there isn’t. If it was highly selected for it wouldn’t be rare.

    Could the programmed organism death mechanism be cancer? If we look on table 10, cancer deaths are subdivided into 20 or more types of cancer in different specific tissue compartments. These are all different diseases. Only one of them could be the programmed death mechanism.

    Could the programmed organism death mechanism be heart disease? Again, table 10 shows that heart disease is subdivided into many different mechanisms of heart failure. At most one of them could be the programmed death mechanism.

    The common causes of death can’t be the programmed death mechanism. Could there be a programmed death mechanism that is only triggered rarely? No, a rarely used trait doesn’t provide enough evolutionary benefit to be selected for.

    In summary, if we look at the actual causes of death in humans, there is no evidence that there is a single programmed death mechanism that is frequent enough to have a significant effect on populations.

  63. daedalus2uon 28 Sep 2008 at 9:51 am

    nwtk, if you have taught science since 1978, perhaps you should get a refresher course; there have been new things learned during that time. DNA does not replicate itself with absolute fidelity ad infinitum. Cancer, the second leading cause of death, is the consequence of DNA errors.

  64. rc_mooreon 28 Sep 2008 at 12:46 pm

    I think this discussion proves my point about a world with 300 year old people.

  65. Roy Nileson 28 Sep 2008 at 1:20 pm

    Yes, but if people lived 300 years, there would conceivably be only one generation of simpletons to tolerate.

  66. nwtk2007on 28 Sep 2008 at 1:31 pm

    daedulus,

    As if I don’t know that. One of the profs on my graduate committee mathematically predicted the presence of the repair enzyme photolyase and another on my committee isolated it. You know, the first repair enzyme ever found. It repairs thymine dimers produced by UV radiation.

    As to cancer, since you brought it up, the cancer cell lines are essentially immortal; Hela cells being a good example. Scientist are still reeling and trying to recover, albeit quietly, from the contamination of these cells in their cultures.

    Any other suggestions?

  67. daedalus2uon 28 Sep 2008 at 2:44 pm

    nwtk, you apparently don’t know that, or if you do know it are unable to appreciate what it means.

    So how does the DNA damage that causes cancer occur in the first place?

    According to your idea that DNA lasts for ever, cancer simply can’t happen. It does happen, and about 25% of individuals eventually die from cancer. Proving that your idea the DNA lasts forever is wrong.

    So what about the enzyme that fixes double strand DNA breaks? Oh, that’s right, there isn’t one. There (probably) can’t be one because once the DNA strand is broken, there is no way to match up the broken ends and glue them back together.

  68. Roy Nileson 28 Sep 2008 at 2:55 pm

    Look, this guy nwtk2007 has to be right because I’ve discovered evidence that he is a child prodigy. By his own admission, he started teaching science in 1978, and at the time he was only 4 years old, having also disclosed on another forum that he was born 10/25/1974.

  69. nwtk2007on 28 Sep 2008 at 7:08 pm

    Roy, I don’t think I’ll explain why the different birthday but if you are that interested in “investigating” me, I am 52 yoa at present.

    My hair is brown and graying slowly but I am in fair shape; running, playing racquetball and now kayaking. (Did 6 miles yesterday preparing for a long one next month.)

    One thing is for certain, I have been around the block and in a wide variety of science related fields and endeavors. However, if I had it to do over again, I would drive for Fed-X and be an Ecclesiastical offspring. In other words I would eat, drink (as you did last night) and be merry for the day ends soon. There is nothing new here and although entertaining, it is vanity.

    Daedulus, your comment

    “According to your idea that DNA lasts for ever, cancer simply can’t happen. It does happen, and about 25% of individuals eventually die from cancer. Proving that your idea the DNA lasts forever is wrong.”

    is too nonspecific to respond to.

    I will point out that many cancers are viral in their origin and not all are based upon mutations to oncogenes and none are related to DNA degradation. A mutation is NOT degradation. It either lethal, leads to more non-sense and is passed on, or is beneficial (rare but necessary for evolutionary change to occur).

    I had forgotten also, that there are specific examples of programmed cell death. Look into embrionic and fetal development. Apparently, with out some form of programmed cell death, development would not be possible.

    As to an enzyme which repairs breaks in the double stranded DNA, I will look into it but I would actually bet that there is one or several or many. Of course in most eucaryotic organisms, there are proteins present, histones I think they are called, which would allow for and aid in the free ends finding each other. There has to be some form of repair for this situation as crossover would require a break in both ends, but I am not familiar with the current thinking on the mechanism. And DNA has this ability to fold into consistent shapes (as does RNA) which allow for recognition of regions which are not recognized by their base sequences.

  70. Roy Nileson 28 Sep 2008 at 7:32 pm

    nwtk2007,
    Maybe you can explain why you defended subluxation on that other forum and denied any adherence to the practice on this one.
    http://chirotalk.proboards3.com/index.cgi?action=viewprofile&user=nwtk2007

    So whether you lied on that forum, or on this one, you have nevertheless confirmed you lied on one of them, and clearly on more than one occasion.

    Your persistent demonstration of ignorance in the various fields of science has already been noted. So much now for your credibility as well.

  71. sonicon 28 Sep 2008 at 8:14 pm

    “Phenoptosis (pheno – showing or demonstrating, ptosis – programmed death) signifies the phenomenon of programmed death of an organism, ie that an organism’s biology includes features that under certain circumstances will cause it to rapidly degenerate and die off. Phenoptosis is a common feature of living species, whose ramifications for humans is still being explored.”

    That’s from wikipedia.

    Guys stop degrading each other.

    Have a discussion about phenoptosis if you like, but please…

  72. Roy Nileson 28 Sep 2008 at 8:55 pm

    That’s already been recognized as applying, for example, to spawning salmon. Plus, as you noted, it’s circumstantial, and not evidence that evolution has programmed life-expectancy limitations per se in organisms. But we’ve already gone over that, and credible sources have been cited in support. None have been cited in opposition.

  73. nwtk2007on 28 Sep 2008 at 9:07 pm

    Sonic you are right but what ever the topic, it always comes to that if one is not perfectly inline with their line of thinking.

    And one is also required to be absolutely on their side or are seen as totally against them.

    For example, look one post previous to yours.

    Roy Niles says that I defended the subluxation in other forums (I think he is stalking me in the internet and hopefully just there.) but I only said I would not dismiss it out right as I have seen some things that chiropractic attributes to the removal of “it”.

    I have also stated that there are forms of “subluxation” which I think exist but not to the point that they block the flow of some “innate” energy or intelligence. That is a chiropractic philosophy but since I am a chiropractor, I am thus guilty by association and always accused of following that philosophy.

    It’s OK though because it helps me to affirm what I know and sometimes I get new insight from their arguments and banter. It is also entertaining. I think that if I were a psychology major working on a PhD and needed a topic for a thesis, I might do one on the psychology of bloggers and blog posters. In many ways they remind me of the psychology I witnessed in the audience of the wrestling arena in Dallas some years ago. I was only there once but I found it very interesting to see the reaction of the crowd and their shifts from opponent to opponent.

    So anyway, Roy, if you would, stop stalking me in the other forums and concentrate on the topic at hand. You are beginning to worry me.

  74. nwtk2007on 28 Sep 2008 at 9:12 pm

    And Roy, did you read the posts you sited? Are htey a defense of the dreaded “subluxation”?

    I mean really, did you actually read them?

    Are you like Joe, commenting of studies and siting “evidence’ without so much as reading it?

    Who is lying here Roy?

    My God in Heaven, it truly is a world gone mad.

    Don’t stalk me no more!

  75. Roy Nileson 28 Sep 2008 at 9:56 pm

    You’re a con artist that singled me out to contend with here on this subject. You didn’t have the guts to confront the author of this blog directly. You went to my blog to try to discredit me. It didn’t work. I went to one of your forums in return. You were exposed as a fraud.

    End of story. You want me to leave you alone. Then don’t fuck with me and you’ll be just fine.

  76. Roy Nileson 28 Sep 2008 at 10:03 pm

    Not to worry. My work here on this blog is done.

  77. daedalus2uon 29 Sep 2008 at 8:57 am

    nwtk, If DNA is not transmitted with 100.00000% fidelity there is degradation.

    You say degradation never happens and DNA stays 100.00000% intact ad infinitum.

    That is clearly false.

    You know that some cancers are caused by deletion of certain genes. That fact falsifies your statement that DNA goes on forever ad infinitum. Rather than admit that DNA doesn’t go on forever ad infinitum you bring up that some cancers are not caused by deletion of genes.

    So what? You say there is no deletion, I bring up a counter example and you claim another example where genes are not deleted. So what? DNA does not last forever. No DNA based organism can be expected to live forever because its DNA will eventually degrade.

    That some tumor cells can live in vitro for a couple of decades says nothing about an organism living for ever.

  78. pecon 29 Sep 2008 at 11:06 am

    Why is there so much difference between the typical life spans of different species, if aging and death are caused by degradation of DNA? Why would the DNA of one species degrade much faster than the DNA of another species?

    A dog, for example, will live 15 or so years, if it doesn’t get sick or hit by a car. It doesn’t matter how well you treat your dog, you know it will not live to 25. Why does a dog’s DNA degrade at that particular rate, if death is not programmed?

    Certain parrots, on the other hand, have very long typical life spans, up to 100 years. Why would their DNA degrade so much more slowly than a dog’s DNA?

    And why doesn’t the DNA of non-sexually reproducing organisms like amoebas degrade and wear out?

  79. daedalus2uon 29 Sep 2008 at 2:24 pm

    pec, there are many things that affect the rate at which DNA degrades. How many of what type of DNA repair enzymes has a big role, as does the level of antioxidant defenses, as does the amount of superoxide that mitochondria produce. DNA repair enzymes are subject to selection too, just as every other trait that has a genetic component.

    Hummingbirds that have evolved for higher altitudes have lower mutation rates. This is attributed to the reduced production of superoxide by their mitochondria as a secondary effect due to adaptation to high altitude.

    http ://www.pnas.org/content/95/2/612

    There are some disorders associated with DNA damage. Fragile X for example.

    http ://hmg.oxfordjournals.org/cgi/content/full/14/suppl_2/R197

    There just happen to be some sites in DNA molecules that don’t replicate as well and that these sites sometimes break during replication. Organisms with longer lifetimes have to have fewer of these sites because they experience early death if they don’t.

    Just to clarify, I don’t think that “aging” is solely due to DNA degradation. I think that aging occurs simply because non-aging has not evolved because there hasn’t been any evolutionary pressure for it to happen. There are a great many different causes of death. Evolving solutions to all of them requires modification to a very large part of physiology.

    Rate of aging and lifespan is an emergent property of organisms that have evolved. It isn’t something that is “added in”, or “programmed”, or that can be regulated independently of everything else. If you want to evolve organisms that don’t die from heart disease, you could select for them, but in selecting for fewer deaths due to heart disease you might increase deaths due to ischemic stroke because the heart doesn’t work as hard so the brain fails from lack of blood before the heart fails from overwork.

    All of physiology is coupled and different aspects of it can’t be arbitrarily changed. Evolution has optimized physiology to a very large extent, but there are still individual variations which affect lifespan, but usually those effects only show up much later in life, during periods where “in the wild”, few humans reached.

    (I put a space after http so the link would post without delay)

  80. nwtk2007on 29 Sep 2008 at 3:15 pm

    Without getting too into this biochemistry and the incumbent circular arguments and semmantics, I will just say, and let you look into it, DNA degradation, if you want to call it that, is also programmed in many instances, or is at least suspected to be.

    As far as out and out DNA degradation is concerned, it is a true factor in DNA held not in living cells but when isolated or derived from a non-living source. DNA changes in living cells are usually not seen as degradation, but some would say so.

    Just food for thought.

    Even fragile sites are thought by some to be selected for in nature in many instances.

    Again, aging is very complex but there is ample evidence to suggest a sort of pre-set limit to organism life span, effected by many, many different factors.

  81. daedalus2uon 29 Sep 2008 at 4:16 pm

    nwtk, no, what you call “programmed” is simply a property that changes over time, and which you have anthropomorphically attributed to a “program”. The DNA of organisms is not “programmed” to degrade any more than rocks are “programmed” to turn into soil or water is “programmed” to evaporate. The weathering of rock into soil is simply an inherent property of different types of rock.

    The idea of a program is simply an ad hoc assumption for which there is no evidence and which makes no predictions which could falsify it. At least none that I can think of. If you can think of a prediction that the idea of programmed DNA would predict then we can see if there is data to support or refute it.

  82. nwtk2007on 29 Sep 2008 at 4:27 pm

    You are way too caught up in the term programmed. It does not imply a programmer but it is meant to be a term for selected for and actively induced to happen given the right set of circumstances.

    But one cannot deny the existance of genes that induce cell death and you cannot deny the existnace of genes that induce DNA degradation, per say.

  83. daedalus2uon 29 Sep 2008 at 4:49 pm

    Programmed cell death known as apoptosis is completely different than programmed organism death. Cells also die due to necrosis. Is necrosis programmed?

    Yes all eukaryotes have enzymes that degrade DNA. They have to because there are circumstances where DNA must be degraded. For example if one organism eats another organism the consumer must degrade the DNA of the consumee in order to utilize its nutrient value. During an infection, one strategy of stopping the infection is to degrade the DNA of the infecting organism. During autophagy, something which all eukaryotes exhibit, DNA sometimes must be degraded.

    Do you have any evidence that there is programmed organism death? Any causes of death that are actively selected for and actively induced to happen under certain circumstances?

    pec, each daughter cell descendent of an amoeba doesn’t survive. Those with degraded DNA survive less well, unless the changed DNA confers some advantageous trait.

  84. nwtk2007on 29 Sep 2008 at 5:04 pm

    There are some who belief that cancer is a program for organism death.

  85. papon 30 Sep 2008 at 1:24 am

    nwtk:

    What is their evidence for such belief? You are implying teleology and then shifting the burden of evidence for such fictions onto your opposition. How would your position be falsifiable?

    Give some real data (not merelya vague quote or link). Explain your position…..or cease in your lazy banter.

    Bringing up vacous “what if” statements as if we were sipping cocoa by the stove is simply boring and it is difficult to engage in seriously, given that you are outright disputing scientific consensus. OK you dissent…good…any reason why?

    I heard in an interview with the famous (infamous if you are a French swimmer) Michael Phelps that it was not uncommon for members of the team to comsume over 7000 calories in a day. I wonder how caloric intake is tied to an individuals metabolism, even if it is induced to be high.

    Aubrey de Grey does not strike me as a kook. However, his ultimate goals, if met in an unexpectedly short period of time ( yes I know this is not likely) would surely lead to dramatic crises linked to overpopulation. Don’t get me wrong, I’m all Ponce de Leon on this one.

    ps
    nwtk: If your’e gonna get all pec on me, at least throw in some wit and humor.

  86. sonicon 30 Sep 2008 at 2:52 am

    daedalus2u,

    From
    Osteoarthritis: An example of phenoptosis through autonomic dysfunction? . Medical Hypotheses , Volume 67 , Issue 5 , Pages 1079 – 1085 A . Yun , P . Lee , J . Doux

    “Phenoptosis, the programmed death of organisms akin to cellular apoptosis, constitutes a type of Darwinian selection that enhances inclusive fitness. It provides a means by which senescent and pre-senescent members can self-terminate if they have incurred sufficient cumulative stress such that their continued survival detracts from inclusive fitness. Sepsis, vascular disease, menopause, cancer, and aging all represent examples of phenoptosis at work.”

    Here are two websites that discuss possible mechanisms for phenoptosis:

    http://www.freeradicalscience.com/showabstract.php?pmid=10648966&redirect=yes&terms=phenoptosis

    http://www3.interscience.wiley.com/journal/117890572/abstract?CRETRY=1&SRETRY=0

    I can understand you not liking the term ‘programmed’, but it is commonly used in discussions of phenoptosis.

  87. daedalus2uon 30 Sep 2008 at 1:22 pm

    Ssonic, I looked at one of the papers on phenoptosis and I find it completely unpersuasive. I have done a lot of reading on mitochondrial dysfunction including during sepsis and I see no evidence that it is any type of “programmed” organism death. It looks to me exactly like the normal control of mitochondria pushed into a control regime where the absolutely necessary protective “fail-safe-off-mode” gets triggered inappropriately and the organism dies. I have an extensive blog about mitochondria failure in the context of immune system activation.

    http ://daedalus2u.blogspot.com/2008/06/mechanism-for-mitochondria-failure.html

    (space after http)

    I don’t see death during sepsis as “programmed”, I see it as a consequence of physiology doing something desperate under extremely desperate circumstances. Evolution has configured the immune system to minimize the sum of deaths due to not enough activation of the immune system (death from infection) and from too much activation (death from mitochondrial failure and multiple organ failure). When you have bacteria floating around in your blood stream, those are extremely desperate circumstances. If those bacteria form a biofilm, the chances of that infection killing you go up enormously. Nitric oxide prevents bacteria from forming a biofilm. During sepsis, the immune system makes gigantic amounts of nitric oxide. I think that NO is to prevent what ever microorganisms are causing the sepsis from forming a biofilm. It is “worth” a significant chance of death for the body to try and prevent biofilm formation because once a biofilm forms death becomes likely. Too much NO during high rate production of ATP from mitochondria will kill the mitochondria.

    As I point out in my blog, that is the normal and absolutely necessary “off” switch for mitochondria, to prevent them from consuming O2 and substrate and generating lethal quantities of superoxide and H2O2. Mitochondria have essentially unlimited capacity to produce superoxide. They cannot be allowed to get into that state where even a few percent of mitochondria could consume more O2 and convert it into superoxide and H2O2 than all the rest of the body’s mitochondria combined.

    The normal off mode of mitochondria protects organisms from mitochondrial failure 99.99% of the time. That sometimes it goes bad and organisms die from mitochondrial failure during sepsis is still a pretty good trade-off.

    I think that all the other degenerative diseases mentioned are much the same, a bad physiological state brought about by normal physiology working at a bad setpoint or under physiological conditions where normal function produces pathology. For example I think that the degeneration of Alzheimer’s is due to ischemic preconditioning being continued for longer than is sustainable because the “off signal” for ischemic preconditioning isn’t sufficient to stop it. I think essentially all of the neurodegenerative diseases are a consequence of that.

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