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Comment by Tarsul | Hacker News Reader

This is (probably) not a Long Covid story but I found that bloodletting (for which I even received money!) gave me back the energy that I was missing for the last few years (e.g. it was impossible to build stamina). I also read about a study about the positive effects of bloodletting[1] that somehow is not all the rage in mainstream news, which I find perplexing. If it might be so easy to improve your health (for some of us), why isn't this discussed or studied more broadly?

[1]https://www.sciencedaily.com/releases/2012/05/120529211645.h...

"the patients who gave blood had a significant reduction in systolic blood pressure (from 148 mmHg to 130 mmHg) as well as reduction in blood glucose levels and heart rate, and an improvement in cholesterol levels (LDL/HDL ratio)."

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I live in an area with PFAS contaminated ground water (which I now aggressively filter.) To me giving blood just kind of makes sense, if there is a class of things that can enter your blood and never leave, and does not replicate on its own, why not perform a regular "oil change" and hopefully help some people at the same time. Some study has been done:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8994130/

The study specifically does not look at the effect on recipients, though the donation centers do not disallow such donations. My presumption is that the donation is a net positive all around. If study comes to show the contrary, I'll certainly revise my approach.

“I’ll do something which might be beneficial or harmful to me (I don’t know) and if given evidence of harm (likely never) I’ll stop doing it.” Ok…have fun I guess.

The person you responded to didn't say anything about harm to themselves. They said there's nothing stopping them from donating even though they're aware of the PFAS contamination in their area.

And from what I understand, PFA contamination has no bearing on whether or not you can donate.

The post implied that doing a “blood oil change” was potentially a good thing. My point is, we don’t know either way, because a study hasn’t looked at that question for health outcomes. It could be doing more harm than good, the parent commenter doesn’t know.

They linked a study in their comment.

The study doesn't show that donation is a good thing. Showing a miniscule reduction in blood markers is not the relevant variable - what you'd actually care about is: do I liver a longer or better life because of this intervention? There simply isn't any evidence that a tiny reduction in PFAS from blood donation results in any improvement in any clinical outcomes. Because we don't know either way, it's also possible that there would be harms from this - as blood donation is not entirely risk free, exposing people to syncope while driving after giving blood, skin complications like infections, or other rare issues we don't even know about.

I assume we are built to lose some blood. I imagine throughout most of our species development, injuries were somewhat common on a regular basis. Just looking at the scars on my own body, from a quite active childhood and young adult period outdoors, I am extrapolating. n = 1

Before antibiotics, nontrivial wounds were often death sentences because of infection.

I never needed an antibiotic to live from these wounds. I’ve needed them from other things (almost died from strep) but not wounds.

You live in a very different world compared to one before antibiotics.

If death were so guaranteed from injuries, I doubt we’d have survived as a species.

Before the discovery of antibiotics, chopping it off was the usual standard of care for serious infections.

It didn't always have to turn into an infection as there are plenty folk methods of preventing that from happening used throughout history - from wound cauterisation to my regional bread + spiderwebs.

The latter was given a scientific explanation in modern times: the webbing contains live penicillium fungi in quantities sufficient to act against microbes.

It's very rare for a minor injury to become seriously infected to the extent that the patient's immune system can't fight it off. Even before the discovery of antibiotics, amputation was typically only used as a salvage therapy in cases of gangrene. They didn't reach for the bone saw just because you had a serious infection.

This is why most women spent most of their adult life pregnant and there's still lingering moral pressure to have children. Societies, especially as they advanced, had real trouble maintaining population through reproduction alone.

You've also probably lived your whole life in urban areas shaped by personal injury lawyers and don't spend your life doing hard labor so you may not have gotten any serious cuts or broken bones because if your lifestyle.

I’ve got scars all over my body from cuts and scrapes. Some even needed stitches, back when that was a thing (now we just use some magic glue)! I’ve been lucky to never have a broken bone, but it wasn’t for lack of trying!

I didn’t live in an urban area until I was in my late 20s.

The modern version of this is called Therapeutic Plasma Exchange (TPE) or Plasmapheresis and it is used to treat a variety of conditions including cancer and autoimmune:

https://my.clevelandclinic.org/health/treatments/24197-plasm...

There are also claims that it improves dementia / Alzheimer's symptoms and popular "longevity biomarkers".

> If it might be so easy to improve your health (for some of us), why isn't this discussed or studied more broadly?

I think you just need to reach for a literature that's a few hundred years older maybe.

The lower blood pressure I can explain by having a lower volume of blood. But the glucose and cholesterol have to go somewhere. Where do they go? Are they filtered in the process after blood letting?

If it's in the blood, doesn't it just leave the body together with the blood?

Yes, but the relative amount per volume blood should be the same. I think that's why he's asking.

If so, the answer is that the body replenishes plasma in a day and red cells in six weeks (redcrossblood.org FAQ). The relative amount does change quickly.

There is very little glucose in circulating blood at any given time. Unless you have severe uncontrolled diabetes (or a similar condition) your body regulates blood glucose level within a low, narrow range. Most glucose is stored in the muscles and liver as glycogen.

Let's just pretend it's accurate and say your body burns 2000 kcal a day. If you have less glucose in your blood overall after giving blood, even if the ratio should theoretically remain the same, your body is still going to burn 2000 kcal anyway, and maybe the blood glucose equilibrium reaches a lower level.

That's interesting - I've had low energy and somewhat raised blood pressure since covid. Maybe I'll give it a go.

If this were the case you could do a natural study on this by comparing menstruating women with the rest of the population

This has been done. Women seem to have certain health benefits that stop after menopause. Reading about it was the first time I wondered whether blood letting made sense.

God, this is so ignorant, the hormonal changes (loss of estrogen) are the cause of increased risks for heart disease and osteoporosis and changes in metabolism post-menopause. Nothing to do with not physically losing blood, FFS.

There are likely multiple causal factors behind the health differences. Hormonal changes are one piece of the puzzle but so far no one has conclusively proved that physically losing blood has zero effect. The research just hasn't been done yet so we can't definitively say one way or the other.

When people donate blood, on average they donate about 10x as much as a woman typically loses during menstruation.

I looked up the amount of blood lost due to a menstruation cycle, and the answer is around 50 ml.

OP's linked paper has "the iron-reduction patients had 300ml of blood removed at the start of the trial and between 250 and 500ml removed four weeks later."

A blood donation removes 500 ml, so about a year of menstruation all at once. You can donate every two months, besides.

So, yes, if there is an effect then we might expect the magnitude of the effect to differ. Or else we'd expect a paper cut to also have the same effect.

Sex biological difference could matter as well.

Menstruating women don't lose nearly that much blood.

Even if they did, the hormonal effects would likely swamp anything else. Which is a huge problem: women are routinely excluded from studies to avoid that, meaning we have no idea what the effects are on women.

There is a significant difference in the rate of major adverse cardiac events between menstruating women versus men and post-menopausal women, even after controlling for age and other factors. The periodic blood loss might account for at least part of the difference although the exact mechanism of action hasn't been clearly established. So it's possible that donating blood (or bloodletting in general) could have a preventive effect.

Yeah sounds like you get your medical advice from the Kremlin. There no conspiracy to hide the medical benefits of leaching, can you imagine if that actually worked? Every doctor in the world would have to be a complete moron not to notice.

I don't know why they decided to use the term "blood letting" but I'm pretty sure some of the benefits being talked about in the response also come from donating blood (which is essentially the same thing)? You calling it "leaching" doesn't seem good faith

Yeah it’s not in good faith. I think it’s really stupid obviously misinformation. Duh.

> I also read about a study about the positive effects of bloodletting[1] that somehow is not all the rage in mainstream news, which I find perplexing. If it might be so easy to improve your health (for some of us), why isn't this discussed or studied more broadly?

If this works, how is anyone going to make money off of it?

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