From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Thu Apr 03 2003 - 07:31:22 MST
On Wed, 2 Apr 2003, Ramez Naam, commenting on my discussion of iron
retention/management in the human body wrote:
> This may also be an example of something that was adaptive during the
> process of human evolution but has become less so in the modern
> environment.
Perhaps -- it would be useful to study the few remaining primitive
cultures to learn whether they (a) accumulate iron at the rate
of steak eating individuals in affluent cultures; and (b) whether
they lose iron at higher rates (due to accidents). Conclusions
about (b) may be difficult because humans have eliminated most
of the larger predators from the planet -- we do not have the
hazard function (even in more primitive cultures) that we once had.
The next time I have an opportunity to speak with Steve Austad
I will try to remember to raise these points with him -- he is
perhaps most qualified to consider these topics.
> I've heard it theorized (maybe even by you, Robert?)
> that humans in ancient times had lower iron consumption (less meat)
> and greater iron loss among males (more bleeding from accidents and
> violence).
I have speculated about this in the past so I might be the source.
But it could be developed independently by individuals familiar
with the complexity of iron management in the human body.
> As a result, the negative effects of extremely high iron
> concentrations in the body were never experienced.
Yes -- so "antagonistic plieotropy" might be context sensitive
(i.e. are we talking about "ancient" or "modern" humans).
That adds significantly to the complexity of the discussion.
(Obviously things like fat and calorie management become
significant here -- we (at least in developed nations) are
not in the same situation our ancestors were with respect
to these nutrients. So the genetic programming for their
management is highly likely to be suboptimal (at least
in the environments we currently live in).
R.
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