i see where you're going, but i still doubt that'd prevent natural death, it just wouldn't be something that is age related.... we may still be able to preserve our bodies in pristine condition for hundreds of years, but not every natural death we face is due to old age.... cancer, illness, organ failure, clogged arteries/heart problems, etc etc...

and the longer and longer we lived, the more and more the chance of us dying one of those deaths would increase, and at some point, if you were even lucky enough to live for so long, it'd be a miracle you even woke up that day....

in all honesty, there is nothing you could ever do to prevent death.. if you found a way to use this so thta your body didn't detoriate, and lived as healthy as you possibly could, you could still very well die a natural death.