Q. I’m a vegetarian who gives blood several times a year. Every now and then my hemoglobin is too low and they cannot take my blood.
How should I time my caffeine consumption so that it doesn’t interfere with iron absorption? I’ve heard I should wait two hours, but is that two hours from the start of my meal or the end? How soon can I eat iron-rich foods after drinking coffee or tea?
A. It’s not the caffeine that’s the problem. Compounds (polyphenols) in many beverages can interfere with iron absorption from foods like beans and leafy green vegetables. Cocoa, peppermint, black and chamomile tea as well as coffee all cut down on iron absorption (British Journal of Nutrition, April, 1999).
Although there has been little research on the time frame for this interaction, waiting two hours after the end of a meal should solve the problem.
