Giving blood is a long-established practice in the modern world, and its immediate reason is to provide blood transfusions for people who need them, for whatever reason.
But physiologically speaking, although certainly not psychologically, the effects of donating a certain volume of blood on one hand, and having a primitive “physician” bleed out an equal volume of blood on the other, should be indistinguishable, provided that in the latter case, the wound through which the bloodletting was done does not result in further complications…
Giving blood is known to temporarily decrease blood pressure, this being the reason that it is discouraged/disallowed for people with a conspicuously low blood pressure (around 80/50 I think). Could the reason that people in ancient times (or less sophisticated peoples in more recent times) performed bloodletting be that they (somehow or another, perhaps through haphazard experiment or accident) observed a correlation between having regular bloodletting procedures performed on them and greater longevity/better overall health even without them understanding at all the concept of blood pressure i.e. why a lower blood pressure is better for one’s health, why bloodletting would even reduce it, or even for that matter, what pressure even was as a physical concept?
I’m guessing that when you don’t really understand scientific cause and effect, that people jump to an observed correlation and just might run with that?
The one therapeutic effect I’ve heard of for bloodletting is with hemochromatosis, where the body can’t dispose of excess iron normally and it builds up in the body; as I understand it blood loss causes some of the excess iron to be removed from the rest of the body as it’s used to make hemoglobin. <checks> In fact, bloodletting is a standard treatment for hemochromatosis. And checking the Wiki article on bloodletting, I see something called polycythemia is also treated by bloodletting, but that appears to be it.
IIRC as another result women suffer less damage from hemochromatosis thanks to menstruation.
There was an article in the Nov 20, 2012 new scientist on this very subject (you’ll need a subscription to read the full article). It appears that giving blood can help with obesity and metabolic syndrome.
edit - but as der trihs notes, these issues in such patients tend to be correlated with elevated blood iron levels - although not at hemochromatosis levels
Bloodletting in olden times was done for unscientific reasons (i.e. “balancing the humors”) and overwhelmingly had a bad record.
With the exception of unusual conditions as already mentioned, there is no therapeutic justification for using it (there are lots better ways of controlling blood pressure and blood lipid levels, for example).
Not really. Not if this works. The standard methods involve drugs that have side effects. Donating blood doesn’t. So if it turns out that this works for some people with metabolic syndrome, it will be a superior treatment.
I was told (by a docent at a historical site a couple years ago) that bloodletting would actually cause a person’s fever to drop.
Temporarily.
Then the body would get back into gear, the fever would rise again, perhaps worse than before: “Whoops, first one didn’t work well enough, we’d better take more this time around!”
The end result of that cycle was often bad news for the patient!!
Note that I know full well that a health volunteer won’t develop anemia as a result of a single blood donation or even routine donations, but their iron levels will almost certainly drop a bit. Someone who was borderline, and perhaps has issues with absorbing iron from food, might have problems.
People with Restless Legs Syndrome may be urged to avoid donating blood even when they’re not clinically anemic, as stored iron levels are often an issue with RLS.
Like any treatment, it would be tailored to the patient. I assume that goes without saying. You don’t give someone with impaired kidney function a drug that relies on good kidney function to be metabolized and eliminated for example. Similarly, you wouldn’t use this approach on someone who had issues that caused it to be contradindicated.
However that said, if the issue is simple iron deficiency, there are prescription supplements that can deal with that issue very effectively. My grandmother was on one for many years and worked well for her.
Some good references there, thanks. I took a look at the NIH articles and discovered that apparently this is well established enough to have warranted a name for the phenomenon - Insulin-resistance-associated hepatic iron overload syndrome (from the next to last NIH cite I think).
Any relation between these apparent improvements in insulin sensitivity and other markers of metabolic syndrome in those with high ferritin levels and the old uses of bloodletting? Seems unlikely.
On the other hand, many things better than donating blood regularly to improve those metabolic syndrome markers in those with high normal or high ferritin levels? Well regular exercise and healthy nutrition pops into mind, but assuming those are already in place, I’m with deltasigma here - this not only has extremely low risk of harm (anemia from regular blood donation in someone who is not low iron stores to start? I don’t think so)* and low cost (time being the expense), it has a benefit to others gained in the bargain. Meds can’t compete with that.
*OTOH, low risk is not none. I know that in Peds kids who get breath holding spells can be treated successfully with supplemental iron, a response that is independent of the presence or absence of anemia, something that is generally explained o the basis of iron acting as a cofactor for certain neurotransmitters. Adults don’t get breath holding spells but I’d hold open the possibility that such has some role in adults as well and that low iron levels could cause some problems in some people. Again, that is a low risk of harm.
It might be worth pointing out that to the extent the connection turns out to be more than just an odd correlation, and rather has a biochemical basis, it isn’t known at this point what that basis might be. But that generally isn’t an obstacle for new treatments inasmuch as drugs are used off-label all of the time for example. Even for approved drugs, if you go to a site like Rxlist and check the clinical pharmacology section to see what the mechanism of action is, it’s a little disturbing how often it’s listed as being unknown and only a best guess is provided. So with something like this, where the risk is slight and even the amount (300ml or 2oz over a half pint) needed to show an effect is small, I would guess that if the connection is real, this will be adopted as common practice for at least some group of patients sooner rather than later.