Does iron cause cancer? On one hand, those who have read my book Dumping Iron as well as my articles on iron may not be surprised, but those new to this topic may wonder that there could be a link between iron, a required nutrient, and cancer, a deadly disease.
This article will take a look at just a small sample of the evidence that iron causes cancer.
Iron reduction lowers cancer rates
A study done by Dr. Leo Zacharski (who wrote a preface for my book) and colleagues reduced iron via periodic phlebotomy in patients with peripheral arterial disease. The study was not designed to reduce cancer rates but to look for an effect on cardiovascular outcomes. But it did reduce cancer. See chart below, which shows the proportion of patients who got cancer in iron reduction group vs control.
Iron chelators can fight cancer
Iron chelators, which are natural or synthetic molecules that attach to free iron in the body and are then excreted, both treat and prevent cancer.
Iron chelators work to both prevent and treat cancer in two different ways.
- Iron reacts with constituents of the cell and damages them. This damage, including to DNA nd mitochondria, can lead to cancer.
- Iron is a growth factor, required for cells to grow. Every free-living organism on the planet requires iron for growth, and the faster they grow, the more iron they require. By lowering iron, chelators deprive rapidly growing and dividing cancer cells of a nutrient essential for their growth.
Curcumin is a natural compound derived from the spice turmeric, and both prevents and treats cancer. It’s thought to do this in a number of ways, but one of the most important is that it chelates iron. So potent an iron chelator is curcumin that mice that get large amounts of it in their food become iron deficient.
Body iron associated with more cancer
Regular blood donors may have a lower rate of cancer. One study found overall a 21% lower rate of cancer among all blood donors. The study used latency periods of from 0 to 15 years to account for a healthy donor effect; in other words, to select only those donors who were free of cancer at the time of the first donation.
Another study found a decreased risk of cancer only among those donors who lost the greatest amount of iron, and only in men. The fact that it was found only in men may indicate that most healthy women of child-bearing age do not have high enough iron to cause cancer, while lowering the iron levels of men, who typically have much higher iron, decreases their risk of cancer.
Higher risks of colon and lung cancer were found among those who had high body iron. (More.)
Iron, coagulation, and cancer
Coagulation is the process by which blood forms a clot, and is intricately regulated by dozens of blood proteins.
Hypercoagulation occurs when this process goes awry, and can lead to internal blood clots causing embolism, heart attack, or stroke.
Hypercoagulation also appears to be related to cancer. Persistent activation of coagulation is associated with much greater odds of a cancer diagnosis.
Dr. Zacharski, whom I cited above, writes:
We suggest that toxicity from elevated ambient body iron levels may explain the association between persistent coagulation activation and incipient cancer. The iron hypothesis is based on biochemical, animal and human data that have linked rising body iron stores, represented by the serum ferritin concentration, to the pathogenesis of several diseases of aging, including malignancy and vascular disease, through iron-mediated formation of oxygen free radicals capable of damaging lipids, proteins and DNA.
The mechanism of iron-catalyzed coagulation activation is, to simplify, that iron damages tissues through oxidative reactions, and this damaged tissue activates coagulation. In turn, this can lead to cancer.
Interestingly, aspirin, which has been associated with far lower cancer rates, enhances fibrinolysis, the process of dissolving a blood clot. A number of mechanisms have been proposed for the association of aspirin with less cancer, and this could be another way.
Animal experiments
Most of what we’ve seen above are associations and do not prove causation between iron and cancer.
However, as Shinya Toyokuni, a noted cancer scientist, writes,
“The carcinogenicity of iron compounds has been unambiguously demonstrated in animal studies.”
Asbestos, cigarettes, and cancer
Asbestos is a well-known carcinogen, but until recently it had always been something of a mystery why.
Tokokuni again: “Several lines of recent evidence suggest that the major pathology associated with asbestos-induced MM is local iron overload, associated with asbestos exposure.” (From “Iron overload as a major targetable pathogenesis of asbestos-induced mesothelial carcinogenesis“.
Cigarettes are also known to cause cancer, and iron is a large component of tobacco smoke. Inhalation of iron in other contexts, for example in miners or foundry workers, also causes cancer.
Conclusion
Cancer is the second leading cause of death in the U.S., and is strongly associated with older age.
As people get older, iron accumulates to excess levels, and this could be a prominent reason for higher cancer rates in older people.
As we’ve seen above, numerous lines of evidence point to iron causing cancer.
It doesn’t appear to be necessary to have very high levels to induce cancer either; dose relationships indicate that any level of iron above the minimum may have an effect.
Keeping iron (ferritin) levels within a safe, low-normal range may be one of the best things you can do for your health and to stay youthful.
PS: For much more on iron as the cause of diseases and aging, see my book, Dumping Iron.
PPS: You can support this site by purchasing through my Supplements Buying Guide for Men. No extra cost to you.
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11 Comments
This modern world. Now I’m wondering about keeping my red meat intake under control, not because of cholesterol, but because of iron. Just can’t win.
Really though, I see my daily vitamin-mineral seltzer tablet has 5 mg of iron. I think I shall have a look around to find an iron-free substitute. What do you make of it — is it a worthwhile supplement at all? Maybe I don’t need that calcium either, as I eat a fair bit of dairy.
https://www.frubiasesport.de/Produkte/SPORT/Inhaltsstoffe (Kalium = potassium, Jod = iodine)
Hi Nick, that vitamin product has its merits, but as you note, iron and calcium, which (for the benefit of other readers) I do not recommend. On the plus side I see magnesium, zinc, potassium, and the vitamins. So it’s a mixed bag. In the US, and I assume in Germany, we have “mature multivitamins” without iron, and some without copper, although all of them seem to have calcium.
I wouldn’t worry about red meat consumption. It has shown little to no link to cancer in epidemiological studies, and if you take other measures such as blood donation or iron chelators, their effects should easily cancel out red meat intake.
Thanks for the quick reply. Yeah, the bit about red meat was pretty much tongue-in-cheek. Still, a lifetime of programming (cholesterol–bad!) takes time to un-do.
I’ve asked at the chemist’s here where we get the vitamins if there’s an iron-free multi, and they didn’t know of any. Just have to dig deeper.
And I should donate blood.
Thank you for the article PD! Do you know how one can increase curcumin bioavailability if ingesting orally? Read it’s very low in humans
Hi RT- a pleasure to write it, this is a topic that fascinates me. Curcumin bioavailability can be increased by taking it with a fatty meal, so if you eat well, something like I do, all your meals should have a fairly high fat content. The other ways are, 1: buy a curcumin product formulated with piperine, which greatly increases absorption. The one on my supplements page is formulated this way. 2. Liposomal formulations of curcumin are available, and these have even greater bioavailability, but are a bit more expensive.
Here’s an easy way to increase curcumin’s bioavailability: have it with some black pepper at the same time. Piperine (which PD mentioned in his response) is a primary chemical in black pepper. A lot of traditional recipes tend to use both of them anyways, which makes things work well if you’re following one of them.
Since I discovered “Rogue”, I have been trying various recommendations by Mangan, with great results. I have lost 14 lbs using I.F. and weight lifting, and hope to lose another ten to twelve to get down to my post college weight in my twenties. I am in my early-mid sixties, and recently had my annual medical checkup. I had my M.D. check my Ferritin, testosterone, and estradiol levels. Ferritin was 200, which from other articles on this site, is too high. Since then I have been taking the Now Brand Green Tea Extract capsules (which is a recommended product by Mangan), three capsules per day.