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Here's a report of a new study that seems to be "on target:"
QUOTE: How does it work? During the aging process, free radicals -- highly reactive byproducts of our cells' respiration -- wreak havoc on our cellular machinery. Mitochondria, the tiny power plants that keep a cell functioning, are especially vulnerable to this type of damage.
The effects can be disastrous -- if malfunctioning mitochondria aren't removed, they begin to spew out suicidal proteins that prompt the entire cell to die. Cell death, on a whole-body scale, is what aging is all about.
Fortunately, younger cells are adept at reducing, recycling and rebuilding.
In this process, damaged mitochondria are quickly swallowed up and degraded. The broken down pieces are then recycled and used to build new mitochondria. However, older cells are less adept at this process, so damaged mitochondria tend to accumulate and contribute to aging.
"Cell survival is dependent upon the ability of the cell to reduce and recycle by a mechanism called autophagy," said William Dunn Jr., Ph.D., a professor of anatomy and cell biology in UF's College of Medicine and senior author of the study, which was published online this month in the journal Rejuvenation Research. "When a cell is under stress, autophagy is turned on to clean up the cell by removing damaged cellular components, while recycling building blocks necessary to rebuild the cell. It's there to protect the cell. But in aged cells, they're basically not able to adjust to stress as well..." UNQUOTE.
Source: http://www.sciencedaily.com/releases/2007/08/070823105436.htm |
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Rats are one thing and people other. It seems that humans are already enough long lived so that CR would produce minimal results in extending our maximal lifespan. It can however prevent chronic diseases linked to premature death. I have some doubts about the people practicing CR as they reduce calories by substituting sugar with chemicals like aspartame, splenda etc., supplement Omega-3 and just "hunt" for their blood markers:
http://www.calorierestriction.org/
http://www.matthewlake.plus.com/results.htm
It may be interesting to investigate what led to the extreme longevity of some primates like the chimp Cheeta (equals 150 years old in human) who doesn't seem to be calorie-restricted:
http://cheetathechimp.org/
http://en.wikipedia.org/wiki/Cheeta
In the cited article they say that stress boosts autophagy. I wonder whether also other kinds of stress wouldn't boost autophagy in humans even more - e.g. strenuous exercise with proper regeneration or heat stress like living in a tropical climate or practicing saunas ... |
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One very likely possibility is that if you keep the free radicals at bay in the first place, there will be much less severe "aging," and so the body can "recycle" well even in advanced age. Remember what Dr. Spindler said:
"The results can be summed up by saying that a calorically restricted animal, even one that has just eaten, is rapidly turning over (renewing) its peripheral tissues. It's an effect that you'd expect, in fact, because insulin is a very powerful anabolic (tissue-building) hormone. Insulin levels fall in calorie-restricted animals, but you get a spike (rapid increase) in insulin levels after they eat, an intense spike, and they're very insulin-sensitive (able to respond to insulin). What I expect happens after they eat is an intense wave of protein biosynthesis under the influence of insulin. As soon as the insulin level falls, they start to break down their proteins again and put the products out into the blood for energy generation. This keeps calorie-restricted animals constantly recycling their proteins so they don't accumulate damaged, oxidized, old, defective and toxic proteins."
Source: http://search.lef.org/cgi-src-bin/MsmGo.exe?grab_id=0&page_id=3807&query=spindler%20insulin%20spike&hiword=
INSULINS%20SPIK%20SPIKED%20SPIKES%20SPIKING%20SPIKY%20SPINDLE%20SPINDLERS%20SPINDLING
%20SPINDLY%20insulin%20spike%20spindler%20
Obviously, it's more complicated than just free radical damage, and antioxidant supplements can do more harm than good. As I've said many times, getting AA out of your cells safely will probably make a huge difference in long-term health. What I've found is that restricting oneself to three meals a day seems to work very well, so long as you eat slowly, and of course, eat the right food. |
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It seems that the FOXO genes determine how long we live. Here they talk about an experiment from 1930 which doubled(!) the rat lifespan:
QUOTE: The first experiments in calorie-restricted diets go back to the 1930s. Laboratory rats and mice fed a severely calorie-restricted diet, but with normal levels of vitamins and minerals, lived almost twice as long as rodents with unrestricted access to food. Experiments with other creatures found that the phenomenon appeared to be ubiquitous in the animal kingdom. Some scientists suggested it was an evolutionary adaptation to surviving hard times until enough food became available. UNQUOTE.
SOURCE: http://www.alternet.org/environment/51394
I wonder whether the SFA versus PUFA dietary manipulations would also result in nearly twice the lifespan ... |
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| That's what Ray Peat thinks, and I tend to agree, but there are a lot of variables that would need to be controlled, and that's not likely to be done any time soon. I also don't think that comparing rats to humans in this context is a particularly good idea. Personally, I find a diet rich in high-quality protein and SFAs (but low in UFAs) keeps me from eating too much. My blood relatives, on UFA-rich diets, seem to always be hungry, whether or not they eat a lot of meat (some do, some don't) or a lot of "simple carbs" (some do, some don't). |
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