What is blocking the iron, in tea/coffee?

[Bluebell]

I had always heard it's the tannins in tea and coffee that do it.

Does anyone know if Peat agrees with that?

I guess having coca-cola when I eat liver is not going to cut it.

 

[jaguar43]

also the magnesium

 

[Asimov]

Caffeine has the ability to chelate iron on it's own. I have no clue what percentage iron blocking is from the caffeine in the coffee however.

 

[Bluebell]

Caffeine has the ability to chelate iron on it's own. I have no clue what percentage iron blocking is from the caffeine in the coffee however.

It seems it's the polyphenols that block the iron, and tannins are one of those.
http://journals.cambridge.org/download. ... 87924f0996

Do you guys have any references for the caffeine and the magnesium blocking iron, I have not heard of that before?