Since I have no education on any of these subjects, this is only my
opinion.
At conception we begin as a single cell. As it divides only its sperm or
egg cells will express telomerase, so that their telomeres will be make
long again each time its cells divides.
So that later when we procreate, the egg and sperm will be able to read
the entire DNA from both parents. That way the human germ line will not
suffer much mutation.
The rest of our cells loose some of its telomeres each time they divide,
this is necessary for if the temomere did not shorten they could be no
human growth.
The telomere acts like a mask when its full length, like a sperm or egg
cell, it can read all of the cells DNA.
When our cells divide there telomeres shorten, that way some of its DNA
cant be read. This caused gene expression within our cells to change,
some genes will be turned on and others off.
As we grow from conception to birth, thru childhood, 21-year-old adult,
then into old age, our cell structures will continually communicate with
each other, about what the body should act and look like, depending upon
the genes that each cell reads from its masked DNA.
Our cells cause Cancer, as they get very old, their gene expression
changes.
Free radicals are very useful to our bodies, and are very well
controlled until we get old.
Then Free radical controlling genes are turned off.
Free radicals then damage our cells DNA.
DNA repair genes are also turned off, so damage cant be repaired.
Our aging immunize system also has some of its genes turned off, the
ones that seek out and destroy mutated cells, DNA damaged cells, and
growing cancers.
Shorting of telomeres is not natures way of protecting us from cancer.
Nature doesnt care about us after we have children and raise them.
But she has gone to a lot of trouble to see that we die of old age and
its diseases.
I really want to know why that is so.
Telomerase expression in a cell group will not cause cancer, unless that
group already has pre-cancer.
If there is pre-cancer, Then we must express telomerase in all the
bodys cells.
The immune system will clean up the cancers.
Caloric restriction works by slowing down the rate that our cells
replicate.
So we grow slower, reach adulthood later, grow old later and suffer the
diseases of old age later.
It changes the way our telomeres count time, they shorten slower.
An animal or human that is restricted of calories, any kind of calories
will have an internal clock that runs a little slower.
Also Since there is less food eaten in old age, you will have less free
radical to deal with, as repair systems are turned off, so you will have
a very low cancer risk.
You will probably die of heart disease 30 years later then normal.