[mfer]

It's more complicated than that. For example, why do those who eat mostly plant based (I mean real plants and not processed foods) have lower rates of cancer if both sides get iron? Iron is essential to live.

It could have something to do with amount. For example, Iron from animal products is easier for the body to absorb and there are MUCH higher levels per gram (e.g., beef has 7x the iron kale does). Is it too much iron?

It could be type. You have FE2+, FE3+, heme iron, non-heme iron, etc. This article points to FE3+. Is there something more there?

Is it some combination of things?

There's a lot we don't know.

[adrian_b]

The study says only the oxidized Fe(III) ions are harmful.

Most iron in food, except that from blood or red muscles is in the form of reduced Fe(II) ions.