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Has anyone read any of the studies in animals using caloric restriction (but with proper nutrition) to study longevity?
Yes. It slows down the rate of cell division and as such it takes longer for telomeres to shorten to the critical point. Studies have shown that you can increase your life expectancy by reducing your caloric intake but the downside is you will not have much energy to do anything. Live longer but less of a life.USCguy said:Has anyone read any of the studies in animals using caloric restriction (but with proper nutrition) to study longevity?
USCguy said:When you say "ROS" are you talking about oxidative damage to the cells of the people running everyday. If so, I guess the first foundation of this would have to be loading up on all the vitamins/anti-oxidants out there...maybe eating a predominantly vegetarian diet would do the trick...plenty of cruciferous veggies and sweet potatoes. I guess this would some what fall in line with the present food guide pyramid recommendations.
FutureDocDO said:Yes. It slows down the rate of cell division and as such it takes longer for telomeres to shorten to the critical point. Studies have shown that you can increase your life expectancy by reducing your caloric intake but the downside is you will not have much energy to do anything. Live longer but less of a life.
Yet we and other researchers have found that a family of genes involved in an organism's ability to withstand a stressful environment, such as excessive heat or scarcity of food or water, have the power to keep its natural defense and repair activities going strong regardless of age. By optimizing the body's functioning for survival, these genes maximize the individual's chances of getting through the crisis. And if they remain activated long enough, they can also dramatically enhance the organism's health and extend its life span. In essence, they represent the opposite of aging genes--longevity genes.
We began investigating this idea nearly 15 years ago by imagining that evolution would have favored a universal regulatory system to coordinate this well-known response to environmental stress. If we could identify the gene or genes that serve as its master controllers and thereby act as master regulators of an organism's life span, these natural defense mechanisms might be turned into weapons against the diseases and decline that are now apparently synonymous with human aging.
Many recently discovered genes, known by such cryptic names as daf-2, pit-1, amp-1, clk-1 and p66Shc, have been found to affect stress resistance and life span in laboratory organisms, suggesting that they could be part of a fundamental mechanism for surviving adversity. But our own two laboratories have focused on a gene called SIR2, variants of which are present in all organisms studied so far, from yeast to humans. Extra copies of the gene increase longevity in creatures as diverse as yeast, roundworms and fruit flies, and we are working to determine whether it does the same for larger animals, such as mice.
http://www.sciam.com/article.cfm?chanID=sa006&colID=1&articleID=000B73EB-3380-13F6-B38083414B7F0000
QuikClot said:This was an early theory for why calorie restriction works; it's no longer in vouge. From Scientific American:
If true, this is the best news possible; it means that CR is not the cause of extended lifespan, but rather it is a hostile enviroment that the body recognises as such and extends the lifespan of the organism.
This means we ought to be able to activate the genes and extend our lives without starving ourselves.
It is also very promising that the trade-off appears to be decreased fertility. Obviously, there must be some evolutionary reason that these genes aren't on all the time. And we all know how evolution feels about decreased fertility. From the human point of view, however, it is a very managable side effect (we could do with a few fewer people on the globe, for that matter!)
After reading this article, I really think they can do it; extend not just our lives but our prime of life (what the eggheads call anti-senescence) with a simple pill regime (they even have a canadidate! It's called resveratrol. (In addition to the article, see http://www.eurekalert.org/pub_releases/2006-02/cp-rpl020206.php.))
Not intrigued? Did I mention it's implicated in fat storage . . . so it makes you lean and muscular as well as long-lived?
Of course this could all go the way of the flying car. Personally, after seeing this article, I'm re-deadicating myself to a healthy lifestyle; I want to live long enough to live even longer.
jonathon said:Hi quickclot,
You did a good job! You are correct in all phases of your analysis. However, try to let the evidence speak for itself. There are drawbacks, though, with the thought of just being able to activate high expression levels of certain genes. Gene expression is highly regulated. So a lot of research is needed to be done to see the results of tweaking the gene expression levels. There is also lack of evidence to date that shows that this method will work in all population groups. Slowing down the metabolic reactions in an organism is not known if it is beneficial in the long run.
QuikClot said:A few things:
* The tone of your reply is rather patronizing. If I wake up some morning and I feel the need for your validation, I'll let you know.
* Of course more research is needed. And it is ongoing. We are at the stage of musing, speculating, hoping and scheming; all of which are healthy spurs to the process of innovation and discovery.
* "Letting the evidence speak for itself" is a non sequitur. Evidence doesn't speak. People do. Scientists are storytellers who try and tell stories that fit the facts.
* These genes do not, as far as is known, slow down the metabolism. CR, as far as we know, does not, and the mooted protective mechanisms do not imply that.
* It is not necessary to say "we don't know if it will work for all groups" when my own sources say that prominiantly. I have read my own sources. We don't know if these genes exist in humans, but since they exist in flies, flatworms, and fish, my money says that we will find them throughout the animals.
jonathon said:FYI: I study Human genetics.
Obviously you dont know what is meant by let the evidence speak for itself.
Genes do have roles in metabolism.
You should read up on metabolic disorders.
You are better of reading primary journals and not second hand information from a lay magazine.
Population studies are important on this subject. I won't get into it though since I need to get to the lab. < http://grants.nih.gov/grants/guide/rfa-files/RFA-AG-01-001.html>
QuikClot said:I'm happy for you. If you expect the Red Sea to part at those words, you're going to be disappointed.
Obviously your study of genetics has left you little time to think about issues of rhetoric, meaning, truth and language, for you have a very naive view.
Of course they do. But there is no suggestion that the aging genes this group is targeting extend life by slowing the metabolism. They work differently. CR has not been found to slow the metabolism.
So should we all, I'm sure.
The sci american article is not "second hand"; it was written by one of the scientists doing the primary research. Apparently he does not share your disdain for "lay" sources.
Incidently, the adjective "lay" is derived from the modern "layman" cf. "laity" which originally meant "not a member of a religious order." Interesting etymology, don't you think?
You do that. I appriciate your specialized professional take on the subject. I might suggest, with all due respect, that we all have different areas of expertise, and different styles of communicating, and it is always good to leaven our advice with a bit of humility.
jonathon said:Quote: "CR has not been found to slow the metabolism."
You have a lot to learn.
CR diets reduce amounts of thyroid hormone, which stimulates metabolism. By reducing these hormones, CR helps model organisms to conserve energy by slowing the metabolic rate.
calorie restriction for either 3 or 12 months induced endothelial nitric oxide synthase (eNOS) expression and 3',5'-cyclic guanosine monophosphate formation in various tissues of male mice. This was accompanied by mitochondrial biogenesis, with increased oxygen consumption and adenosine triphosphate production.
Understanding the mechanisms by which calorie restriction works and developing medicines that reproduce its health benefits have been tantalizing goals for decades [see "The Serious Search for an Antiaging Pill," by Mark A. Lane, Donald K. Ingram and George S. Roth; Scientific American: The Science of Staying Young, 2004]. The phenomenon was long attributed to a simple slowing down of metabolism--cells' production of energy from fuel molecules--and therefore reduction of its toxic by-products in response to less food.
But this view now appears to be incorrect. Calorie restriction does not slow metabolism in mammals, and in yeast and worms, metabolism is both sped up and altered by the diet. We believe, therefore, that calorie restriction is a biological stressor like natural food scarcity that induces a defensive response to boost the organism's chances of survival. In mammals, its effects include changes in cellular defenses, repair, energy production and activation of programmed cell death known as apoptosis. We were eager to know what part Sir2 might play in such changes, so we looked first at its role during calorie restriction in simple organisms.
What media? If you've ever looked into the biomedical aspects of aging you'll see that telomeres do play a role in aging. Genetics class will also mention it. Although there also seems to be a intrinsic clock but no one has been able to tell what it is up to this point.Moxxie said:telomere length was mentioned by a previous poster, but I honestly think that telomeres have been overplayed in the media.
FutureDocDO said:What media? If you've ever looked into the biomedical aspects of aging you'll see that telomeres do play a role in aging. Genetics class will also mention it. Although there also seems to be a intrinsic clock but no one has been able to tell what it is up to this point.
Matthewlake said:I am 21 years old and have been doing Calorie Restriction just after I turned 20. I currently eat around 1700-1800 calories a day and it is really not difficult.