How Blood Donations Deplete Iron

blood and iron: how to optimize iron levels

A reader asked me a question that stumped me at first, so here’s the question, and my answer as to how blood donations deplete iron.

Q: “How is it possible to remove as much or more iron as ordinary food rapidly replaces? When I count the number of things whose contents individually constitute 100% of “RDA” or even higher, it strikes me that I’d have to just about bleed out every day to get rid of it all.

“Can you show an “iron balance”, with quantification showing elimination rates from various actions vs intake from various foods? That would be very helpful.”

A: Your question genuinely stumped me at first. I was wondering whether I had overlooked something. A blood donor loses about 250 mg of iron from his body iron stores with each donation, out of total body iron stores of 3 to 4 grams.

According to the NIH, average daily iron intake for an adult American man is about 20 mg, although not all of that is absorbed; as little as 10% is absorbed, or 2 mg, depending on lots of factors like food macro composition, alcohol intake, sugar consumption, use of supplements, etc. Meanwhile, the RDA is 8 mg (0.8 mg absorbed) so you see the problem: intake is 2.5 times the minimum necessary, which can ultimately lead to high body iron stores (high ferritin). 

At that rate of 2.5 mg a day absorbed, in 100 days, you’ve made up for the blood donation. But we do know that donating blood lowers iron levels quite well, so what gives?

The answer is that the 2 mg of iron absorbed daily is at a steady-state of body iron. Iron overload, unless extreme (genetic or some other reason) happens over years, slowly. Somewhat like if you gain 1.5 ounces of body weight a month, in 10 years you’re 10 lbs overweight.

Normal daily iron losses for an adult man are about 1 to 2 mg. So the iron you absorb daily just keeps even with losses. If you donate blood, and lose a lot more, absorption increases.

But if you lose blood via donation, phlebotomy, or being mauled by a bear, it will take longer than 100 days to make up for your lost iron at steady-state rates. If you lose a lot of blood, absorption really ramps up. 

In my book, I calculated that one annual blood donation is enough to keep ferritin in a low normal range, assuming low normal ferritin to start with. (With a high starting ferritin, a higher rate of donations is necessary to get down into the low normal range.) That’s ~250 mg a year of iron.

I calculated here that 75 mg of aspirin might get rid of 25 mg of iron daily, which exceeds daily intake.

I trust that all makes sense. The iron you ingest daily isn’t all added to body iron, because you lose a small amount daily, and when you donate blood, the same applies.

I discussed other aspects of blood donation, iron, and transfusion here.

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  1. Matt says:

    Hi Dennis,

    Just listened to this and had to tell you, in case you haven’t heard it yet- the relationship between iron and aging came up in Dr. Rhonda Patrick’s latest interview. Jump up to 16 minutes:

    • P. D. Mangan says:

      Thanks, Matt. I cited some of Gordon Lithgow’s research in my book. Also sent him a copy, although I never heard anything back.

      • Bill says:

        PD I watched this video this morning. It is excellent. Gordon strikes me as a typical Scot. Reluctant to highlight his work unless he thought it through completely.

        I watched an interview with Dr Peter Attia as well with her. Again it was excelent though I did repeatedly think ‘let the man speak woman’ for both interviews. ! Hope I am allowed to say that here 🙂

        • P. D. Mangan says:

          Bill – oh, yes, you can say that here. I’m part Scot myself, mother’s side were from Ayrshire. Maybe why I’m so modest, and cheap. (Not sure if I’m allowed to say that.)

  2. B1tman1ac says:

    This is a good clinical trail that goes into some detail about iron & hemoglobin stores and replinishing them.

    This article seems to indicte that healthy centenarian men have hemoglobin levels in the 12.4 g/dl range which is under the mandatory levels for being able to donate (13.0 g/dl).

    I my self have donated whole blood over 30 times. Usual 2 to 5 times per year. My hemoglobin normally hovers around the normal range of13-15.5 g/dl and I get that checked every time I donate. However, my ferritin (iron) is always low when I get it checked during my yearly checkups, always 30-40 ng/ml. This even though I occasionally supplement with a vegatarian iron formula. However I’m also active and run a lot which bleeds iron from the system too and is another reason why I sometimes have to supplement to meet my needs. More so lately.

  3. Oskar says:

    Is that for real that only aspirin can remove 25mg of iron? So 10 day fast with little bit of aspirin would reduce the iron burden as much as donating blood?

    • P. D. Mangan says:

      Oskar – that calculation is highly theoretical. In reality, aspirin won’t chelate 1 to 1 with every iron atom in your body, most of which is protein bound and not available for chelation.

  4. Joshua says:

    The paper about aspirin maybe being an actual iron chelator is quite interesting. Nice work, PD. It makes me kind of want to start a daily aspirin regime. Though since I’m only 36, I think the risk/benefit analysis probably doesn’t yet work in my favor. (I’d be worried about it impairing adaptations to strength training as well.) But when I hit 50 or so, this might be another reason to start trying a daily aspirin, methinks.

  5. Ted says:

    PD, do you have any info on links between donation & albumin, or iron and albumin levels?

    • P. D. Mangan says:

      Albumin is sensitive to protein intake and malnutrition, the biggest factors as far as I know. In theory, lots of plasma or platelet donations, say weekly, could decrease albumin, but it’s unlikely to be a factor in whole blood or red cell donations. Iron doesn’t affect albumin levels, but may cause albumin to become oxidized.

  6. Nathan says:

    Here’s a data point. I got my ferritin level tested in early November, 2016 and it was 339. I had it tested last week after three whole blood donations (every 8 weeks) and it is down to 163. I haven’t done any chelation.

    I’m a 5’11”, fairly muscular 205 lb 44-yo male. I do weekly Body By Science HIT workouts.

    The main difference I’ve noticed in my health is that it is very easy to spurn carbohydrates and I eat ketogenically now.

    • P. D. Mangan says:

      Good to know, Nathan. Your donations are getting your ferritin down about 50 points each, which was the upper limit of what i wrote in my book (30 to 50 points a donation).

      • Nathan says:

        Since my last report on April 29th, I’ve donated three more units (one single and one double “Power Red”) and my ferritin is down to 71.

        My plan from here on out is to donate a single unit twice a year and retest ferritin every couple of years.

        • P. D. Mangan says:

          Excellent work, Nathan. 6 units donated got you from 339 to 71, or roughly 45 ng/ml for each donation, which accords well with what I wrote in my book, at 30-50 ng/ml per donation. You’ve greatly improved your health risks.

          • Joshua says:

            I’ll contribute another data point here. Last January my ferritin was an alarming 343 (ng/ml, I think). I embarked on a blood donation quest and ended up donating 4 times (the 4th time was a “double red”, so a total of 5 units). Fast-forward to now and my ferritin is down to only 47! I was about to do another double-red donation, so I’m glad I got tested — I’m guessing that last donation would’ve put me into anemia territory.

            So, to summarize: for lowering iron, blood donation works!

            To be sure, I’d also made 2 other changes: cut back somewhat on lamb (love that lamb), and increased green tea consumption, especially at lunchtime when I eat meat. But still, I imagine the great majority of the reduction is due to the blood donations.

          • P. D. Mangan says:

            Thanks, Joshua, great data point. If your other iron reduction methods counted for a little bit, then your blood donations may have dropped your ferritin about 50 points a unit, exactly what theory says.

  7. Bill says:

    B3, Niacin is also an iron chelator. In Feb I had a ferritin iron level of 50. It is now down to 30 after starting to take Niacin 1000mg tablets on March 1st. to boost HDL-C levels which had fallen to 34.8 in February, ( Probably due to losing about 7kgs. in January-February.)

    My HDL-C did indeed increase to 54, on the 2/5/2017, from 34 in early Feb.

    But there was also a decrease in blood ferritin iron levels despite a low carb/high fat diet with lots of meat protein.

    It is good & very interesting learning all this and coming to understand the inter-connectedness of it all. Thanks PD for the commitment of so much time and effort and thought to helping us all learn !

    As I want to continue boosting my HDL-C level to about 90

  8. Rob H says:

    Hi Dennis, I’ve just come across this article from the latest edition of the BMJ:

    You may only see the abstract here, but the article goes on to say that based on (from memory) 7.5 million person years of observation, both red processed and unprocessed meat increased 9 causes of mortality. They believe that the main effects are mediated via haem iron (both processed an unprocessed red meat – ie beef, lamb and pork) and also nitrates and nitrites (processed red meat). white meat (Poultry and fish) were actually found to be protective however. Would you consider cutting back on red meat in the light of this article? Or would you say it is irrelevant for someone who only eats UNPROCESSED red meat, and donates blood in order to cut down on haem iron?

    Hey, by the way it just struck me: your ‘rogue’ views on iron seem to suddenly have become mainstream if the BMJ has now come round to your point of view re (haem) iron!! Have a great weekend, Rob.

    • P. D. Mangan says:

      Rob, I’m very skeptical about that study. For one thing, the healthy user effect: those who take care of their health are much more likely to have eaten less meat over the past few decades, since health authorities said it would raise cholesterol, and you should avoid it. Also, a protective effect of white meat doesn’t make sense to me; less iron of course, but why it would protect 9instead of be less toxic) doesn’t jibe. Lastly, the paper appears to have an agenda: “In an editorial,2 John Potter, professor of epidemiology at Massey University in New Zealand, said that contemporary meat consumption is equally bad for the planet and for human health. The destruction of rainforest for farming animals, and greenhouse gases from animals, contribute more to climate change than fossil fuels for transport, he wrote.

      “As with many contemporary problems of resource overuse and maldistribution, we need to decide whether to act now to reduce human meat consumption or wait until the decay of sufficient parts of the global system tip us into much poorer planetary, societal, and human health,” he concluded.”

      Processed meat – bacon, ham, sausage – is part of the Mediterranean diet, and it doesn’t seem to hurt them.

  9. Hey Dennis!

    Took your advice and donated. They told me I had a ’15’ when I donated (they test your iron levels). Any idea what that means? I didn’t ask for mols or mg’s.


    • P. D. Mangan says:

      Hey Daniel! That 15 is your hemoglobin and is normal. Blood bank staff always say they check your iron, but they don’t, ever. Hemoglobin is not iron, it’s an iron-containing protein in the blood.

  10. Scott says:

    Hi PD,
    Thank you for writing Dumping Iron it has been a valuable resource these past months on my journey to lower my iron level. October 2017, 61 years old, discovered I had a Ferritin of 869 after high liver enzyme tests. AST 67, ALT 145. Was experiencing brain fog after I ate, just didn’t feel well. Went to liver specialist, negative for hemochromatosis but a carrier of H63D. Started blood donation every 56 days as the red cross allows. Ferritin was 567 one month after 1st donation, 336 one month after 2nd donation, 204 one month after 3rd donation. Just had new liver enzyme test done , AST 33, ALT 50. Feeling much better, brain fog is almost completely gone, didn’t really improve until after 2nd donation. Ironically liver specialist said lowering my iron level was up to me, didn’t think it was necessary! Liver biopsy showed stage 1 fatty liver and stage 1 iron level. Have to be patient, at my present level of reduction approx. 38% with each donation, I’m looking at 3 more to get to a ferritin level of 50. Just a head’s up PD, in the book Protien Power Lifeplan by Michael Eades, MD he predicts almost exactly the rate of ferritin lowering starting at different levels when the iron overload is caused by metabolic syndrome and not hemochromatosis. I will update as I continue to donate with my ferritin and liver enzyme levels. Thanks again PD!!

  11. Scott D Smith says:

    Hello again P.D.,
    Have a question, in Dumping Iron you talk about the high iron content of pet food. You go on to say at the end of Is Commercial Pet Food Killing Your Pets that you’ve stopped feeding commercial pet food to your cat. What do you feed you cat now? Thanks Scott

    • P. D. Mangan says:

      Hi Scott – my cat eats raw meat, usually chicken gizzards and livers, as well as beef liver, kidney, and ground beef. Sometimes canned fish. Trying to switch him over to beef because of high omega-6 content of chicken, and there’s evidence that lots of those are bad for cats, just like for humans. And he’s a lean, mean fighting machine.

  12. Scott says:

    Hi P.D., had my 4th blood donation today, all were 56 days apart. As I stated above my ferritin has been coming down nicely. My hemoglobin has been going up after the 1st donation – 15.5 – 14.9 – 15.2 and then today 15.4. In your research is that normal? I can’t find any reference in your book or online, except the hemoglobin going down with donation. Any thoughts? Thank you

    • P. D. Mangan says:

      Hi Scott. All the results look like they could be within error measurements of the instrument used to measure it. That’s really not a lot of variation. Normal for men is 13.5 to 17.5 (Mayo Clinic) so all your results are in a tight range.

  13. Scott says:

    P. D.,

    I just watched your interview with Dr. Zacharski, and the exact question I asked you earlier about my hemoglobin going up as my ferritin is coming down is answered perfectly with the table in figure 1 showing that’s what happens as you de-iron. As ferritin comes down iron is released due to iron autophagy which makes your hemoglobin go up. Getting more bang for your buck as he says. All I can say is wow. Plus it shows exactly where to go for a ferritin level, the sweet spot right around 80. Thanks again P. D. for having this sight, and your book it has helped so much through this process of lowering my iron (ferritin of 869) and all the symptoms I have had. The interview with Dr Zacharski makes you see just what has been happening. Scott

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