Not only does it inhibit absorption of iron in supplements or foods, it seems to actually wrest iron from body tissues. Some medical practitioners use it to treat people who have iron-overload/hemochromatosis.

Not only did I discover that taking milk thistle for 2 months reversed my hard-won increases over the previous 6 months in my serum ferritin (I am on iron supplementation prescribed by my doctor due to very low serum ferritin levels), but there are many research articles about it. I will list the links for several published articles below, so you can read about it yourself.

http://findarticles.com/p/articles/mi_m0ISW/is_2003_June/ai_102372145/:
http://www.nutritionalwellness.com/archives/2010/may/05_bone.php
http://www.ncbi.nlm.nih.gov/pubmed/20628405
http://www.ncbi.nlm.nih.gov/pubmed/18458640
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3098397/?tool=pubmed
http://www.ncbi.nlm.nih.gov/pubmed/9468229
http://www.ncbi.nlm.nih.gov/pubmed/11410232

If you have low or even moderate iron stores, please think very carefully about taking milk thistle, or any supplement that includes silymarin (a component of milk thistle) — which I have just discovered is unfortunately in the new multivitamin I went to great expense 2 weeks ago to import a 6-months’ supply from the States — because it’s so effective in ridding the body of iron.

So check your iron. Get a blood test. And if you are post-menopausal, don’t assume your iron can’t be low. It definitely can. But get it tested.

Janie, I love what you’re doing–sorry to repeat myself, I’ve said it before, don’t mean to sound like a broken record (did I just age myself?!). My iron experience is as follows: when my sex hormones shifted around the age of 12 and I started menstruating, all my internal systems got knocked off balance, and stayed rather deranged for the next 35 or so years until I stopped with the menstruation business last year. (Accurate as it may be, I hate to make this assertion openly, because immature men, hostile to women (who, sadly, have been controlling the allegedly-civilized world for thousands of years—-but I digress!), have gone mad belittling women, questioning our competence and even our sanity, on account of the challenges some of us face with our reproductive capabilities. So somehow I’m going to have to work on a way of stating my case without leaving myself open to attack from the peanut gallery.) I fell into a depression when I was 12, and it was really like being underwater for these past 35 years, occasionally breaking the surface for a time, only to sink again. I also became chronically anemic, but didn’t start supplementing with iron regularly until I was in my 20s, and by golly did that help! The iron mitigated symptoms of fatigue and poor sleep which contribute to feelings of depression. My favorite product, Thompson’s Blood Builder, went off the market, and in my 30s I became an avid devotee of Nature’s Plus HemaPlex, which has an astounding 85mgs of elemental iron in it, together with a synergistic blend of other supplements (no, I don’t work for the company!LOL). Oddly, when I started taking an antidepressant, Zoloft, in my mid-late 30s, my anemia began to resolve, and I could not tell you why. It’s not as if I started eating better because the depression abated, I don’t think my diet changed at all. But dealing with hypothyroidism has taught me that there is such an intricate and delicate balance between the 100s of hormones in our bodies, that a teeny-tiny shift in one can impact many, if not all, of the others. So maybe the shift in estrogen/progesterone and all the other sex hormones when I was 12 impacted the serotonin/dopamine levels which are theorized to control depression; and maybe taking iron boosted serotonin, and when I boosted serotonin with Zoloft, I didn’t need as much iron—yikes! Add in that in my early 40s I was diagnosed with subclinical hypothyroidism and started taking Armour thyroid—my brain is getting tired trying to keep track of all this stuff, it’s beginning to get like a mental Rubik’s Cube! Anyway, I’m always interested in things we can do to improve our health and quality of life without dependence on pharmaceuticals, as grateful as I am that they are available. So I like reading about diet & nutrition, and I have seen a lot of warnings about iron, and I didn’t understand what all the fuss was about until I read that, oddly enough, our bodies have no mechanism to eliminate excess iron, which is the weirdest thing in the world, because too much iron is a really bad thing, it’s quite toxic. The only way to get rid of it is to donate blood (which is a great thing to do in any event), or take some kind of inositol (IP6 if I remember correctly, but check that, if you need to). I’ve read that excess iron intake kills a great many children every year, though I haven’t yet bothered to Google that fact for back-up. But for men, and for post-menopausal women who are not losing blood every month any more, iron supplementation is a big no-no. The first time I visited my rheumatologist after my periods had stopped, I asked to have all the requisite iron-specific blood tests done because I had continued to take my beloved Hema-Plex, because I wasn’t sure if I was just skipping periods, or finished altogether. The hormone tests confirmed menopause, and not surprisingly, my ferritin level was well above range. So the new box of Hema-Plex sits in my kitchen cabinet, waiting for someone to come along who will be able to use it. And I get a little bananas when I read food labels, because so much of our food is fortified with iron, and calcium, and all this stuff that I really wish they would leave to the consumer to choose. In any event, you get my point.

Thanks for all your hard work and forever changing our lives!

(From Janie: It’s my pleasure. I suffered SO deeply all those years that it propels me to NOT let this happen to others. Information rocks!)