--- In morelife@yahoogroups.com, Paul Wakfer <paul@...> wrote:
[big snip]
> 2) Any loss of essential body cells will require their progenitor cells
> to divide in order to replace those lost cells. While this is not going
> to be a problem acutely (if occurring only a few times or very
> infrequently), if done chronically (as some people are advising), it
> will, over time, deplete the division potential of the cells that
> produce the blood cellular components, and if done sufficiently often
> the doubling time potential of those cells (the Hayflick limit) may be
> reached and become a limiting factor to lifespan. (There is already
> good evidence that the Hayflick limit plays a part in the exhaustion
> of white cell division that occurs with AIDS.)

One thing to consider is that average blood loss during menstruation
is 35 ml with 10–80 ml considered normal (from Wikipedia on menstrual
cycle). Assuming 12 cycles, the total comes to 0.42 liter, or 0.89 US
pints per year lost to menstration, just a bit less than the typical
donation.

Perhaps donating once a year might affect the gap between average male
and female life expectancies, if the over-mineralization theory of
aging has some merit.

Speaking of the Hayflick limit, I was surprised that a search for
"astragalus" didn't turn up a match in this group's archives. I've
participated in discussions
(http://www.imminst.org/forum/index.php?showtopic=19921) on using
astralagus extract along with a small dose (I use 250 mg) of chitosan
to increase its bioavailability (http://pmid.us/16715776 -- I don't
have the text, but the study apparently reports that 0.1% chitosan
increases absorption by over 60 fold).

Of course, does it really work to extend telomeres and in which
tissues are still open questions.

StephenB