How much does tea/tannins reduce absorption of minerals ?

[*Di]

I love tea after/during meals, usually black or black decaf, but I've heard that tannins interfere with the absorption of minerals - does anyone know how much they interfere - you know, a little or a lot, and is it all minerals or just a few ?

Thanks !!!

[AJP]

I don't know how much tea interferes, wish I did because I love it also. But I thought it was the oxalic acid in tea that blocks minerals, not tannins.