There is no effect on “heme” iron. Caffeine has no effect on iron absorption so if someone is concerned about lack of iron there is no point in switching to decaf coffee. For healthy people, there is no issue with iron absorption. But for those who are iron deficient, probably best to skip having coffee or tea with a meal.
Does coffee and caffeine inhibit iron absorption?
Can coffee and tea interfere with iron absorption?
Summary: The polyphenols in coffee and tea inhibit iron absorption by up to 90%. The more polyphenols you consume, the more they may inhibit absorption.
Does coffee deplete iron?
Coffee does not have the ability to lower your iron levels. But it does have the capability to stop your body from absorbing further iron. According to this study, a cup of coffee hindered iron absorption by 39% when paired with a meal like a hamburger. This goes to show that coffee does inhibit iron absorption.