Interesting article and I won't dispute the fact that blood-letting was practiced fervently in the past. I'd like to see a few serious double-blind studies before I'll jump on the bandwagon.
There are significant numbers of people that regularly blood let, blood donors (about 6 times a year for those that keep at it).
They tend to have less heart attacks (but it isn't clear if that is due to the health screenings required to donate or if there is some impact from the blood letting).
(I do realize there is another group of people that regularly lose iron, but that isn't an optional medical procedure)
Probably stating the obvious here, but the reason they stopped the practice was because people did such studies.
If bloodletting worked on any common injuries or illnesses, we'd still be using it for those cases. Even then, we'd probably have tried to find medication that produced the same benefit to try to avoid the infection risks.
I'm not going to look it up now, but there was a post on lesswrong.com summarizing health things-to-do that had evidence behind them. IIRC it recommended for men (but not women) to donate blood every year or two.
I have a vegan friend who is always battling low iron levels. After reading the NYT link, I told her that her spinach and whole grain intake might be making things worse.
The links between high iron levels and diabetes were also very interesting.
Donating blood seems to have positive impacts on insulin sensitivity. I heard about an interesting study where they had meat eaters donate blood, and it significantly improved their blood glucose - http://wiki.dandascalescu.com/summaries/life_extension_confe...
Giving blood is one of those things where it's low risk, can help others, and has some science behind the benefits presumably by reducing iron. Have been meaning to get into it.
The rise of the Iron Age actually was highly correlated with an increase in bloodletting. Although copper was widely available, trade routes were needed to access tin needed to manufacture bronze during the bronze age. This situation created stable borders and relative peace.
When iron smelting techniques were discovered no one needed to depend on trade routes to manufacture weapons. At this point borders destabilized and bloodletting increased.
Of course the article is about a totally different situation.
