4 replies to this topic

[caruga]

I've read about the hazards of iron. But one proclamation is that once it is in the body it doesn't get excreted. SO it just stays in the body forever? If that's true then any intake of iron whatsoever would eventually accumulate to poisonous amounts. Common sense says the body has a way of dealing with this, so what is it?

[niner]

I've read about the hazards of iron. But one proclamation is that once it is in the body it doesn't get excreted. SO it just stays in the body forever? If that's true then any intake of iron whatsoever would eventually accumulate to poisonous amounts. Common sense says the body has a way of dealing with this, so what is it?

Common sense wins again. Iron that you consume through diet and supplements that isn't absorbed is eliminated fecally. See Fig 1 of this article. Iron that is absorbed has other elimination pathways; skin cells that are sloughed off is one little-appreciated mechanism. Any form of blood loss, primarily menstrual in pre-menopausal females, but also through cuts, donation, blood tests, and occult bleeding is the other chief mode of iron excretion. Normal excretion rates are pretty low; on the order of a mg or two is typical. Here is a paper on excretion.

[leha]

And here is a good overview of the whole process, highlighting the importance of the body's ability to tightly control the absorption of iron:

Human Iron Metabolism

[pamojja]

I've read about the hazards of iron.

Tried to keep iron from supplements down too. But was really surprised, after tracking my nutrient intake, that I would get already 27 mg of iron per day from my diet alone.

However, my iron store values were all rather at the lower end of lab reference ranges. Then I took upto 20g of vitamin C per day, which allegedly increases iron absorptions. However, 1 year later my body iron stores decreased even further.

So I guess individual absorption/elimination must be huge factor determining iron toxicity.

[david ellis]

Dr Eades, of Protein Power, has a different take on iron levels. He feels that there is a reason ferritin levels should be kept low, around 50 ng/mL. The reason to keep ferritin levels low is that in case of accident or strokes, extra iron will increase the oxidation damage. 50 ng/mL of ferritin is supposed to be enough to cover two events of serious blood loss. The reference range for ferritin in the linked study goes up to about 350 ng/mL. Seven times more iron will do a lot more oxidative damage when blood leaks into body tissues.

Insect bites and untreated wounds were a large part of our evolutionary past. Our past needs to store blood are gone. Blood donation is a reasonable precaution and a good deed.