Iron is a necessary nutrient, and low levels in the diet, faulty absorption, or excessive bleeding can cause low levels of iron, leading to anemia, cognitive deficits, and immune dysfunction. The blood is the major storage organ of iron, containing about 70% of all body stores of it.
On the other hand, excess amounts also cause health problems, as can be seen with the primary example of iron overload, hemochromatosis, a genetic condition that causes the body to absorb too much iron from the diet. Hemochromatosis can lead to cancer, liver failure, and heart disease, and left untreated definitely kills people. The treatment for hemochromatosis is phlebotomy, that is, bloodletting. Getting iron levels down to normal in hemochromatosis allows essentially for the disease to be cured.
Iron in the natural world reacts with oxygen and rusts. Inside the body, it essentially does the same thing, causing high levels of oxidative stress.
The difference in iron levels between men and women has consequences
Men of course die younger than women, and higher rates of heart disease in men is one of the main reasons for this. Men also have higher iron stores than women, a consequence of the fact that premenopausal women lose small amounts of blood every month through menstruation. Since blood is the major iron storage organ, losing blood means losing iron. Post-menopausal women catch up with men in terms of iron stores, and in later life women also catch up in terms of rates of heart disease.
The body tightly regulates the amount of iron that is absorbed from the gut, but other than blood loss, as well as small amounts of iron being lost through sweating, the body has no way to rid itself of excess iron. The reasons for that seem clear enough: in the bad old days, blood loss due to wounds and injuries as well as intestinal parasites was a common occurrence, and dietary sources of iron, mainly meat, were not always plentiful. Therefore there was no need for the body to have a mechanism to rid itself of excess iron. In fact, hemochromatosis is probably around because having only one gene for it gave its carrier an advantage in being able to absorb more iron from food.
Way back in 1981, Jerome Sullivan proposed that the difference in heart disease rates between men and women was due to higher levels of iron in men, which accumulate with age. (Lancet.) Sullivan proposed testing this through therapeutic phlebotomy. Since his hypothesis, much work has confirmed that he was on to something big.
Calorie restriction and aging: Is less protein the cause, or less iron?
As we’ve repeated quite a bit on this blog, calorie restriction is the most robust treatment known for extending the lifespan of experimental animals. It is usually said that restriction of protein is the reason for extended lifespan, since if calories are restricted but protein is not, the lifespan extension is abrogated or does not occur at all.
But meat, the major dietary source of protein, also contains large amounts of iron. Could less iron accumulation be the real reason, or at least part of the reason, why calorie restriction extends lifespan? As it turns out, there’s good evidence that it is.
Consider that inhibition of iron absorption – interestingly, by putting tea in their food – increased the lifespan of Drosophila by >20%. (Mechanisms of Ageing and Development.) The authors of that study say, “It is concluded that iron accumulation is a significant factor contributing to senescence.”
In rats, calorie restriction led to much lower levels of iron with age, and as a result, levels of lipid peroxidation, a measure of oxidative stress, were markedly suppressed. (Mechanisms of Ageing and Development.)
In a paper just out this month, it’s reported that “iron starvation” induces mitophagy and extends the lifespan of C. elegans. (Current Biology.)
Although there a number of other similar animal studies, we’ll add just one more: calorie restriction downregulates iron absorption and leads to less iron accumulation. (Rejuvenation Research.) From this study:
The results suggest that the anti-aging effects of CR might partially lie in its capacity to reduce or avoid age-related iron accumulation in the brain through down-regulating expression of brain hepcidin—the key negative regulator for intracellular iron efflux—and that facilitating the balance of brain iron metabolism may be a promising anti-aging measure.
From all this we see that it is entirely possible that one of the reasons, perhaps even the major reason, that calorie restriction extends lifespan is because it causes less iron to be accumulated with age.
What is the evidence in humans?
In humans, aging leads to decreases in insulin sensitivity and higher levels of fasting blood glucose. These are also characteristic of diabetes. Is there any evidence here that iron accumulation plays a part in these, in both aging and diabetes? Yes.
Medical scientist Francesco Facchini has done much work in this area. He found that in patients with insulin resistance – what he calls “carbohydrate intolerance” – therapeutic phlebotomy such that the patients got to “near iron deficiency” caused an approximately 50% improvement in insulin sensitivity. (Gastroenterology.)
He also found that iron depletion via phlebotomy led to an improvement in cardiovascular risk factors. (Annals of the N.Y. Academy of Sciences.)
Facchini studied lacto-ovo vegetarians – who eat eggs and dairy but not meat – along with a comparison group of meat-eaters, and found that the vegetarians had both lower iron stores and much better insulin sensitivity. To discover whether iron and insulin sensitivity were related, he took six of the meat-eaters, and through phlebotomy dropped their iron stores to the level of the vegetarians; the meat-eaters’ insulin sensitivity increased by 40%. (British Journal of Nutrition.)
Blood donors have lower disease risk, much lower
A different group of researchers looked at a group of blood donors, and carefully matched them with a group of non-donors by age, BMI, waist-to-hip ratio, blood lipids, smoking status, and blood pressure. They found that the donors had increased insulin sensitivity and lower insulin secretion. (Clinical Chemistry.)
Since insulin resistance increases with age, as do iron stores, it can be seen that less iron means less aging.
Another study looked at blood donors compared to non-donors. This was a prospective study; anyone who had donated blood in the 24 months preceding the start of the study was deemed a donor, then they were all followed for an average of 9 years. When adjusted for age, examination years, and all the coronary risk factors they could think of, the donors had an 88% decreased risk of heart attack. (American Journal of Epidemiology.) Awesome, I think.
Of course there are confounding factors to be considered. Blood donors are healthier than non-donors to begin with. That’s why the statistics were adjusted for coronary risk factors. One factor they didn’t adjust for is years of education, a proxy for IQ. Blood donors tend to be not only healthier, but better educated and more civic-minded, so this could skew the results. Nevertheless, there are good physiological reasons for believing that lower iron stores make for better health, so I have no trouble believing that blood donation causes better health.
A randomized controlled study looked at the effect of reducing iron stores via phlebotomy on cancer rates. (Journal of the National Cancer Institute.)It found that those randomized to phlebotomy had a 35% lower cancer rate, a 60% lower rate of cancer mortality, and and a 50% lower rate of all-cause mortality. Proof doesn’t get much better than that.
Iron and cholesterol
When I discussed this issue over on Twitter, one respondent wrote that we should try to be objective here and not make iron into a villain, since we did that with cholesterol, and that ended badly. Not only was cholesterol not a villain, but the prescribed method of avoiding it, low-fat eating, had a major role in the obesity epidemic.
It’s perfectly true that iron is a required nutrient, and in many parts of the world, iron-deficiency anemia is a serious problem. But it tends not to be in the affluent Western world, where dietary sources of iron are readily available, and bleeding from wounds and intestinal parasites is uncommon.
Cholesterol and iron are similar in that the body requires both; but the body makes cholesterol itself, iron no. The body also closely regulates cholesterol levels; if enough is taken via food, then internal production decreases, and vice versa. With iron, the only method the body has to control it is to increase or decrease absorption; there is no way to get rid of it, while cholesterol can be metabolized. It seems clear enough that there’s no physiological advantage to having a high ferritin level; the minimum is good enough.
A further line of evidence: polyphenols
Polyphenols from tea, coffee, chocolate, wine, and berries are known life extenders, and it’s usually thought that most of their benefit comes from activating the cellular energy sensor AMPK, making them essentially calorie-restriction mimetics. It turns out that many of these also bind to iron, rendering it inactive and available for excretion. (Cell Chemistry and Biophysics.) This could be a major component of their health-giving properties. Quercetin, for example, has potent iron-binding capacity. (PLOS One.)
Aspirin is also known to extend lifespan, by lowering cancer rates among other things. It is also known to activate AMPK. It also causes intestinal blood loss, an average of about 5 ml daily. (JAMA.) So iron loss could be one way that aspirin’s health benefits work.
Coffee and tea are also known to have many health benefits, and they both reduce iron absorption from the gut, coffee by ~40%, and tea by 64%, which are large decreases, I think it fair to say. (AJCN.) So again, the health benefits of coffee and tea could be due in part, perhaps major part, to inhibition of iron accumulation.
What to do about excess iron
From Facchini’s studies, we know that any amount of iron over the minimum can be deleterious and promote aging. The test used to determine iron stores is ferritin, the normal range of which for a man is 12 to 300 ng/ml. Facchini phlebotomized his patients down to a level of about 30 – lower than that there may be problems, such as anemia. But even at a level of 70, insulin sensitivity was substantially decreased. So it seems that for anti-aging purposes, we may want a level above 30, but not much.
The major solution to excess iron is bloodletting, which is easily accomplished through blood donation. Donation of 500 cc of blood, which is about the size of a typical blood donation (450 cc in the U.S.) leads to the loss of from 200 to 250 mg of iron. Amazingly, one month after a single 500 cc phlebotomy in healthy blood donors, ferritin levels went from 75 to 38, and in a 2-hour glucose tolerance test, plasma insulin was reduced by 37%, and plasma glucose by 19%.
It appears that not much in the way of blood donation is necessary to obtain real benefit.
If you have a high ferritin level, then more donations may be required. Ferritin testing requires a doctor’s order, but is relatively inexpensive and performed by almost all labs.
Beyond blood donation, inhibition of iron absorption can slow iron accumulation. This can be accomplished by drinking coffee or tea with or within one hour after a meal. The supplement inositol hexaphosphate strongly chelates iron, and can be used to lower iron stores.
It also goes without saying that iron supplements of any kind should not be taken except under a doctor’s supervision and advice.
34 Comments
Nice article
Does that mean for someone following a low carb and higher protein diet, his or her meals should always be paired with tea or coffee to inhibit absorption of iron?
Regarding aspirin, are you aware of any research on the optimal dose and timing for health maintenance?
If you want to inhibit iron absorption, then yes, coffee or tea with meals is a good idea. As for aspirin, I’ve always been cautious in discussing it, because most doctors don’t want everyone to take it, and with reason, since it can cause bleeding, sometimes serious. As I wrote in my latest book, the attitude is changing somewhat, since it’s now seen that aspirin, besides being useful in secondary prevention of heart attacks (that is, when the patient has known heart disease), also has strong cancer prevention effects. In epidemiological studies, aspirin’s effects in prevention topped at 80 mg/d, a baby aspirin. More than that had no effect on CVD or cancer prevention, but does have more side effects, like bleeding.
Does l-theanine activate AMPK?
Tea does activate AMPK, not sure about theanine. Theanine does activate heat shock protein https://www.sciencedirect.com/science/article/pii/S1756464612000539
and extend lifespan in C. elegans. https://link.springer.com/article/10.1007/s00394-012-0341-5/fulltext.html
The Nikoley / Dogders article also presented a case that dairy is a strong inhibitor of iron absorption, and even conjectured that the kosher prohibition against eating dairy with meat was actually a pragmatic way of avoiding anemia in an iron-poor desert nomadic lifestyle. So have a cheeseburger instead of a hamburger, and eat steak in the northern Italian style: with a big huck of Parmesan cheese.
Leeches! The ancients had it right.
Coffee after meals; wine with meals. Chocolate dessert. It’s humorous in how old-school it is. Jeanne Calment was famous for eating chocolate every day (and smoking).
That AJCN article is interesting. The 39% number was from drip, but they get much better results with instant. “When a cup of drip coffee or instant coffee was ingested with a meal composed of semipurified ingredients, absorption was reduced from 5.88% to 1.64 and 0.97%, respectively, and when the strength of the instant coffee was doubled, percentage iron absorption fell to 0.53%.”
Superstrong instant FTW! I wonder where espresso lies.
Sadly, looks like Calment was a lying tax fraud.
Richard Nikoley recently had a href=”https://freetheanimal.com/2015/05/enrichment-diabetic-chronically.html”>couple of (long) guest posts showing a correlation between obesity and heart disease and iron enrichment in wheat. The French Paradox: they don’t enrich their wheat.
Given what we’re starting to figure about the gut microbiome and “safe starches,” it’s made me wonder if all the paleo/low-carb success was really from abstaining from wheat.
Whether it’s gluten (v. doubtful IMO), glyphosphate (possibly), or iron (Wow, if it’s that), the bad rep wheat has gotten keeps seeming more and more justified, even if it’s not specifically wheat’s fault.
Did you see this on fish oil supplements?
https://www.washingtonpost.com/business/economy/claims-that-fish-oil-boosts-health-linger-despite-science-saying-the-opposite/2015/07/08/db7567d2-1848-11e5-bd7f-4611a60dd8e5_story.html
Well, that’s interesting, I’ll have to add it to my list of things to think about. Check out, e.g., work on the omega-3 index, where blood levels of omega-3 fats are inversely correlated to risk of heart attack. The Omega-3 Index: a new risk factor for death from coronary heart disease? Quote: “The Omega-3 Index was inversely associated with risk for CHD mortality. An Omega-3 Index of ≥8% was associated with the greatest cardioprotection, whereas an index of ≤4% was associated with the least.” See also this chart on the omega-3 index: https://roguehealthandfitness.com/wp-content/uploads/2014/05/nihms-22135-f0002-300×245.jpg
Chris Kresser has written about this in the past. I believe the confounding factor on fish oil may be that the oil in fish oil capsules often is oxidized (i.e. rancid) by the time that it’s consumed. This may neutralize or even reverse it’s potential beneficial health effects.
The solution? Eat actual fatty fish, the way our ancestors would’ve. (But beware of mercury as you go up the food chain..)
Joshua, thanks. the problem is, there’s some evidence that oxidation is required for fish oil’s health benefits. See here: https://roguehealthandfitness.com/how-do-omega-3-fatty-acids-work/
As for fatty fish and oxidation, I’ve heard this argument before, and I don’t understand how it could be thought that the oil in fish that’s cooked at high temperatures could be less oxidized than fish oil that hasn’t been cooked from capsules or bottles.
Great post!
This causes me to reconsider many nutrition issues. Vegetables are good for health Well, vegetables have compounds that inhibit iron absorption. Whole grains (at least relative to white flour) are good for you. They also contain compounds that inhibit iron absorption and avoid the iron added to fortify white flour. Some fruits have polyphenols that reduce iron absorption too.
Another problem: citrate increases iron absorption. But magnesium citrate is the best form of magnesium supplement. So take magnesium on an empty stomach?
A high tannin and high phytate diet for lower iron absorption? More potatoes and wheat bran? Here is a table of phytate (inositol hexaphosphate) in foods.
People have been using IP6 (inositol hexaphophate) supplements to chelate iron and reduce serum ferritin for years.
https://www.longecity.org/forum/topic/67219-help-with-ip6-iron-chelation-safety/
https://www.longecity.org/forum/topic/65948-recommended-brands-of-ip6-dosing/
If your goal is to reduce iron for general health reasons and you’re not eligible to donate blood, then IP6 might be an alternative. Few, if any, doctors would approve therapeutic phlebotomy unless you suffer from hemochromatosis and have a massively elevated iron level.
LEF was publishing articles about iron 15+ years ago so the idea isn’t new, but there’s much more evidence to bolster the case now. So I’m glad to see it’s getting renewed attention here and elsewhere.
This is an excellent discussion of phytate, cancer risk, iron.
I think one should eat foods with vitamin C separate from foods that contain iron in order to reduce iron absorption.
This is another reason to avoid processed food, since so many are fortified with iron.
In middle school science class our homework was to put cereal in a bag and crush it as fine as possible. Then in class we put it in a beaker with water and put a magnet next to it. My ubiquitous brand of oat cereal looked like it had a nail filed into it. The whole class was disgusted more than when we had dissected animals. Probably because we weren’t eating the animals.
Actually, iron food enrichments are poorly absorbed—which is why they add so darn much of it. What most people aren’t considering is that all that unabsorbed iron from the enrichments just irritates the gut and blooms pathogens. And there is plenty of research showing this (not to mention it’s well known that iron pills promote gut problems).
Check this out…
And research shows that iron supplements can promote gastric distress even at low doses.
When all that poorly absorbed iron fortification passes to your gut, I’d imagine that it impairs our flora’s ability to process gluten. This might explain why the gluten free fad is so popular in fortified countries. And I’d imagine that it’s no coincidence that gluten only became an issue in Sweden and the US when iron enrichments were significantly increased. Sweden banned iron fortification in 1995 and the Swedish coeliac epidemic was said to have ended in 1996 (now attributed to either breastfeeding changes or vitamin D supplementation changes). Frankly, I don’t understand why they haven’t looked into the obvious inflammatory properties of iron fortification and its correlations to iron enrichment increases in the US and Sweden.
Interestingly, food enrichments are associated with obesity (Zhou 2014) but not for why you’d think. The B vitamins they add to refined foods are done to “normalize” your appetite, which would otherwise falter on a diet of pure refined foods. This has been known since the 1920s when Osbourne & Mendel discovered that vitamin enrichments were necessary to sustain appetites.
The government has now been forced to recommend “whole and enriched grains” thanks to lobbying from the food industry. 90% of Americans eat enriched grains and their health falters. Without the enrichments, they’d be naturally compelled to crave their nutrients elsewhere (what happens in most of Europe). Having no fortification requires people keep traditional cooking alive—those traditions were invented to manage appetites with naturally occurring nutrients and to promote health. If people tried to eat lots of pure refined nutrition-less grains they’d become deficient and stop eating (pellagra, beri beri). Actually this used to happen during the 19th century—it was called “dyspepsia” and people lost their appetites from eating refined foods. The cure was fiber-rich bread and fiber-rich cereals (see Kellogg’s sanitarium and Graham bread).
Again, it’s a natural defense mechanism innate in all animals to lose appetites from a diet of mostly refined foods and it was well documented in the early medical literature on vitamins. That doesn’t happen anymore thanks to enrichments. Enrichments enable humans and animals to eat foods they would otherwise not be compelled to eat without some form of supplementation (Banting kept his appetite high from exercise and by supplementing his refined foods with yeasty vitamin B-rich beer).
It’s the food industry that did this—mainly led by the American Bakers Association (ABA). Look at their website and you’ll be amazed at how much lobbying they’ve done to promote enriched grains into the food pyramid. It’s shocking. The ABA singlehandedly lobbied to raise the enrichment levels right before the obesity epidemic started. That’s not a coincidence. It was done to keep people from losing their appetites for enriched foods (Americans were eating significantly less carbs than any other Western nation at that point in history and the food industry was trying to reverse that trend). The enrichments “normalizes” the appetite so that you can keep eating that otherwise refined food. (The lack of key minerals like Mn and Cu/Zn reduces the body’s ability to process its own oxidative stress). The ABA promotes enrichments, like the idea that folic acid reduces birth defects, claiming a relative reduction of NTDs by 36% when in reality it’s only an absolute reduction of -0.015% in NTDs from fortification. Can you imagine? In what world does any industry spend that much time lobbying for the ability to dose all men, women and children of all ages with something that reduces a health issue in just pregnant women by only 0.015%. It’s totally nuts.
The healthiest countries are the ones that don’t enrich their foods. France actually has a purity law that prevents “traditional” bread from having additives. So the French eat a lot of white flour but are compelled to get their nutrients elsewhere (i.e. traditional foods and beverages) and they are healthier for it.
Shawn, thanks for the interesting comment. Not to dispute what you say, as it makes a lot of sense, but it seems rather speculative. Have you come to these conclusions on your own? Or is there anyone else out there who’s saying this? Because this line of thought is all new to me.
Great article! I remember first hearing about the rather scary implications of iron overload about 4 years ago when I read Anthony Colpo’s The Great Cholesterol Con. I had no idea it was even a potential issue, especially so for men, and I’d never even seen the iron issue discussed anywhere else.
Though, I’ve definitely noticed the iron topic gaining traction in just the last year or so. Richard Nikoley recently posted a whopper of an article that strongly implicates iron enrichment to various foods as being a significant culprit behind the rather insidious iron overload problem in the developed world.
I’m not sure how this issue hasn’t gotten more attention from the mainstream medical industry, especially when it’s rather simple and easy to treat, i.e., bloodletting.
As someone who has recently shown a slight increase in iron levels and has lost family members due to hereditary hemochromatosis this issue keeps me vigilant about my overall health. In the very near future I plan to be donating blood on a quarterly basis.
Do you know if black tea (India tea/Orange Pekoe/Tetley tea bags) has the same iron chelating effects as green tea? A cursory look on the web, the studies seem to be all about the good effects of green tea.
I like white flour and make my own bread. I wonder if I could throw a couple of mg of IP6 into the mix and mop up the added iron (which is about 20mg/lb flour = 3.3mg per bagel), since all white flour is enriched in the US.
It’s interesting the calcium is sort of an antagonist of iron (I think that’s why dairy is good at anti-chelating), ie more calcium absorbed implies less iron absorbed. On the other hand, calcification of blood vessels is one of the pre-cursors of cardiovascular disease, which sort of implicates calcium. I don’t have a deep knowledge of any of this and was wondering if you had an opinion if calcium has been redeemed.
The tea used in the study on iron absorption was black tea, so that should work just as well in decreasing iron absorption. Most of the work on the health benefits of tea has been done on green tea, but every time I see a study using black tea, it seems to work just as well for whatever it’s being tested for. As for calcium, I don’t think it’s been redeemed as a supplement, since it’s associated with higher mortality. As part of dairy however it seems quite good, and full-fat dairy eating is associated with lower mortality.
Unfortunately, the Red Cross doesn’t let one donate blood if one were in the UK for more than 3 months between 1980 and 96 owing to mad cow/Jakob Creutzfeld disease.
ok,, so that is why there was a research before taht followed people who drank coffee and they found out that the ones who drank more mugs a day have lower mortality rate…
might be because of iron inhibition
Love the website PD. I just donated blood for the first time after reading this article.
Question: I donated a pint of whole blood (ok every 56 days), but other options include platelet donations, double red blood cell donations (only every 112 days) and plasma donations. Any thoughts on what might be the best type of donation for health issues?
Thanks, J. Platelet and plasma donations will not deplete iron, only whole blood donations will. Body iron is mainly stored in hemoglobin, a component of red blood cells. A whole blood donation is approximately half red blood cells and half plasma. So, for your own health, whole blood donations are the way to decrease your ferritin (iron) levels.
As for pint vs double donations, it probably comes down to how much you value convenience – a double donation only takes time every 4 months – vs recovery time – a double donation will leave you feeling less energetic for longer than a single whole blood donation. You probably couldn’t handle a gym session for a while after a double donation for instance. Personally I’d probably go for the single whole blood donation.
PD – good stuff!
Here’s one for you: *When* to donate, relative to one’s workout?
Just Before: Maybe you’re tired, but perhaps presents a positive (hermetic) stress to the body?
Just After: Cells damaged during workout (muscle, otherwise) will have a greater chance of being bled out than having to float around and have the body deal with.
How to time vis a vis hormonal release (older guys, say). Immediately just after workout, the GH hasn’t spiked, so dumping blood won’t ‘waste’ any GH, but perhaps donating four hours, say, after a workout might give away valuable GH?
Do you really think you’d be fatigued after double red? Whenever I’ve given whole blood (middle-aged, here) I’ve never tired at all. Just impatient at “having to sit” and wait. How could giving double red (a massive ferritin benefit) possibly fatigue one days later for a workout?
Thanks for any thoughts.
Great pic, BTW. Post more?
Thanks, Ross. What happens with a blood donation is that you lose about 10% of your red cells. Plasma volume is quickly replenished, while red cells will take a few weeks to get back to normal, using iron stores remaining in the body. The result is for a few weeks you have a lower than normal hematocrit, which is the percentage of red cells in the blood. You might go from a hematocrit of, say, 42, to one of 38. Your VO2 max will decrease, since red cells are the oxygen carriers to your muscles and organs. So, it is possible you wouldn’t feel fatigued as such, but you would almost certainly have lower exercise capacity. That all goes double for a double whole blood donation.
I don’t have any particular setup, whatever works for you. But if you feel weak or lightheaded working out in the days after a donation, best tread lightly, go easy on the workouts, maybe even skip one.
I have had in mind to post some more pics, one of those things that I can’t seem to get around to, but I will.
“With iron, the only method the body has to control it is to increase or decrease absorption; there is no way to get rid of it, while cholesterol can be metabolized.”
I wonder how it is that we could accumulate such excess iron if we still have the ability to regulate its absorption. I imagine that there circumstances that would cause the body to uptake larger than usual quantities of iron but wouldn’t our physiologies likewise, regulate the further absorption in an effort to balance the bodies total iron stores and thus, mitigate oxidative damage?
That’s a good question. In some people, perhaps, iron regulatory mechanisms don’t work well. For instance, it’s not uncommon for a middle-aged man to have a ferritin of 300, while the average is about 150. Why would someone have a ferritin that high? Conditions like diabetes cause a dysregulation of iron. Also, some observers think that iron supplements and fortification play a role – although again, why the body doesn’t just cease absorbing iron, I don’t know. In evolutionary terms, natural selection doesn’t really care if you accumulate a lot of iron when older, since iron is a growth factor, and all nature cares about is if you have enough to grow and reproduce.
Non-heme iron must be combined with vitamin C, in order for the body to absorb it efficiently. Vitamin C is a powerful antioxidant.
Maybe that’s the body’s way of saying “i’m only going to absorb as much iron as I can handle”. Unfortunately, heme iron will bypass that mechanism.
As always, it would be good to have more data. Most of the research is either done on animals or done on humans following a standard American diet. I’m not sure what research on heme iron, in particular, has been done in relation to low-carb/high-fat, low-carb/high-protein, keto, carnivore, etc. What is causing the iron overload in the first place for most people in industrialized countries? There definitely is evidence that diet does play a major role.
Based on anecdotes shared by Dr. Paul Saladino and Dr. Shawn Baker, eating more meat when on a carnivore diet sometimes lowers iron levels and resolves iron overload. “Fortunately, excess iron levels don’t seem to occur to any significant degree on a carnivore diet,” writes Baker, “It’s likely that underlying metabolic disease and inflammatory states contribute to excess iron storage. In general, a carnivore diet tends to improve those conditions, and that may be the reason why high storage levels as assessed by serum ferritin don’t seem to be a problem, even though carnivore dieters have a relatively high iron intake” (The Carnivore Diet).
Baker suggests, “we need to re-evaluate some paradigms” (Twitter thread). Speaking of the Inuit, Baker argues that, “They ate a lot of iron, they did not suffer iron overload. Humans have that capacity to chronically adapt… Iron overload is associated with chronic diseases of which they did not suffer from”; to which Amber L. O’Hearn added, “So either iron “overload” doesn’t matter on that diet, or its not happening. Either way is favourable.” This argument is supported by what is known about the diets and health of traditional hunter-gatherers (Sally Fallon & Mary G. Enig, Guts and Grease: The Diet of Native Americans).
Although some blame metabolic disease on iron overload, according to Baker it’s “very likely reverse causality and all meat tends to fix metabolic disease.” These doctors are not observing iron overload in most of their patients following meat-heavy diets that are low-carb and otherwise healthy. Saladino, in talking with Joe DiStefano, claims that the only strong evidence of health risk for heme iron comes from research done on calcium-deficient mice (Stacked 015 – Debunking The Game Changers with the Carnivore MD, time mark 57:05; for discussion of other evidence about iron from this perspective, see what Saladino wrote in Wilks/Kresser Debate Breakdown). Most people aren’t mice and most people on animal-based diets aren’t calcium-deficient.
Iron is tightly regulated and so on a carni diet it could be that the body realises the danger and self regulates as much as it can, but with non heme plus vitamin C etc then you could potentially get to much and bypass this regulatory system, iron overload can stem from hemochromatosis but also from various gut issues, a damaged gut may affect Hepcidin which regulates iron absorption, IP6 can fix this by affecting Hepcidin, it can also make you absorb more Iron by affecting Hepcidin in the opposite direction.
Turmeric, black tea, seeds/nuts (Phytates) beans/lentils, and avoiding high vitamin C foods with an Iron meal may help and calcium apparently reduces absorption by 50%, eggs also reduce absorption (Phosvitin)