

The Arsenic Eaters of Styria - fasteo
http://www.ultimatehistoryproject.com/arsenic-eaters.html

======
jandrewrogers
Interestingly, arsenic has long been suspected of being an essential nutrient
in mammalian biology. There are wasting diseases that are nominally caused by
extreme arsenic deficiency and adding arsenic to animal feed in certain
regions of the world (presumably with extremely low environmental arsenic
levels) has been practiced because it increases animal weight and fertility.
And fact is, in some parts of the world (including some regions of the US),
extremely high natural arsenic levels in the water and environment exist at
several times the EPA maximum designated levels with no obvious adverse
consequences. I do not think there is any rigorous scientific evidence for
acquired tolerance but it is a possibility; at a minimum, populations living
in naturally very high arsenic environments don't seem to accumulate notable
pathologies as a result.

The old saying that "the dose makes the poison" probably applies here, and
bioavailability of the arsenic forms probably plays a role. However, the line
from poison to harmless is rarely straight and in many cases is bimodal i.e.
too little is as bad as too much. Many common vitamins have a similar toxicity
curve. Even alcohol consumption has a bimodal distribution in terms of its
effects on mortality. Arsenic having a bimodal toxicity would not be
surprising, even though it is presumed to be linear by the EPA. It would be
somewhat surprising to learn that a high degree of tolerance can be developed
but not unprecedented.

An alternative hypothesis is that arsenic bioavailability varies considerably.
What may be interpreted as tolerance is actually a circumstantial lack of
bioavailability. There is scientific evidence lending credence to the idea of
incredibly low bioavailability of dietary arsenic in some cases such that it
might be possible to consume large quantities without actually absorbing it.
Some plants are known to be aggressive concentrators of environmental arsenic
without being particularly toxic to critters that eat them. In some contexts
most of the arsenic may go in one end and out the other.

Arsenic is quite interesting from a biochemistry perspective. It can be
extremely toxic, which is well understood, but the variability and the effects
in lower doses is not. Plenty of interesting research still to be done.

~~~
fasteo
Reading further about its mechanism of action[1], it seems like it decouples
the electron transport chain. There are other substances (for example, the
famous DNP fat burner) that do this was well, and they all seems to have a
narrow therapeutic index[2].

Take home message: Don´t mess with the mitochondria and, as you commented,
research into its therapeutic potential.

"The dosage makes it either a poison or a remedy" [3]

[1]
[http://en.wikipedia.org/wiki/Arsenic_toxicity#Mechanism](http://en.wikipedia.org/wiki/Arsenic_toxicity#Mechanism)

[2]
[http://en.wikipedia.org/wiki/Therapeutic_index](http://en.wikipedia.org/wiki/Therapeutic_index)

[3]
[http://www.brainyquote.com/quotes/quotes/p/paracelsus300347....](http://www.brainyquote.com/quotes/quotes/p/paracelsus300347.html)

------
mlamat
I was born in Cilli, now named Celje, part of Slovenia, but have never heard
of this.

------
Someone
Google gave me
[http://www.ncbi.nlm.nih.gov/pubmed/23070617?dopt=AbstractPlu...](http://www.ncbi.nlm.nih.gov/pubmed/23070617?dopt=AbstractPlus):
"Possible positive selection for an arsenic-protective haplotype in humans"

PDF at
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3553437/pdf/ehp....](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3553437/pdf/ehp.1205504.pdf)

