calcium....blocks absorption of vitamins?

[golfbobbyhill]

A buddy of mine claims that calcium can block the absorption of vitamins?

Any truth to this?

[AstronautJones]

Calcium can block the absorption of some vitamins like zinc. It doesn't block/slow absorption of all vitamins though, otherwise they wouldn't put it in multivitamins.

[gettinjackT]

It will fight for absorption with some minerals, such as zinc and magnesium, but not to a very significant degree.

[restless]

Originally posted by gettinjackT
It will fight for absorption with some minerals, such as zinc and magnesium, but not to a very significant degree.

Yes, it can compete with some minerals, but not with vitamins (zinc is not a vitamin, by the way). I know that with magnesium this only happens with a dosage of more than one gram of calcium and in the presence of phytate (present in whole grains mainly).