In the latest column, Cecil talks for a while (ie a paragraph) about people eating arsenic as a health regimen. In fact, chickens and pigs have been extensively fed arsenic in recent years because it makes them grow much faster. Of course, it wasn’t long before the public put an end to that.
By what process does arsenic help chickens? It’s certainly not a hormone or other sort of direct growth stimulant. No one really knows, but it could be just its ‘toxic’ nature, administered at a low dose, that does all the work. A similar process has been observed in other ‘poisons’ and stressors and carries the label hormesis.
Of course there is no such thing as ‘poisons,’ only doses. The dose makes the poison, and almost every substance has a non-trivial amount that will kill you (water poisoning, oxygen toxicity, vitamin overdose). ‘Poisons’ don’t exist, but what we call poisons are just things that we often enough encounter in the environment in the necessary concentrations.
However, the repeating observation that many of these ‘poisons’ even become beneficial at certain levels takes this age-old but oft-forgotten piece of wisdom to a whole new level.
The public and scientific misunderstanding of the issue of stressors (meaning toxins and other ‘harmful things’) – our irrational and baseless preoccupation with bitching about stressors in their lowest doses (like microwaves from cellphones or traces of metals) – is one of the most profound confusions in modern thought, and will be one of those things that years later we’ll ask “holy shit, what were we thinking?” It’s ironic, because that’s, of course, what we say about such things as bloodletting, which, like feeding arsenic to chickens, likely in some cases did good. It’s a shame that Cecil’s column didn’t broach this general controversy of doses being poisons and hormesis.
Link:
http://www.straightdope.com/columns/080321.html