Q&A: Are coffee and tea iron-blockers?

I’ve heard that coffee and tea can block the body’s ability to absorb iron. Is that true? —S.L., Montpelier, Vt.

Yes, but that applies to only one type of iron, and most people have high enough iron levels that they needn’t be concerned about it. Coffee, tea, and red wine can inhibit the body’s ability to absorb nonheme iron, the iron found in plant and dairy foods. The reason: Those beverages contain compounds that bind to the mineral in your intestine. One small study found that drinking a cup of coffee while eating lowered the amount of nonheme iron absorbed from the meal by 39 percent; a cup of tea reduced absorption by 64 percent. Red wine also appears to have a potent iron-blocking effect, based on other research. But the beverages don’t appear to block absorption of the other main type of iron, heme iron, which is found in meat.

In any case, most Americans consume more iron than they need. (Even vegetarians, who get iron exclusively from plant sources or supplements, appear to have no higher rates of iron deficiency than meat eaters.) So unless your doctor says you suffer from low iron levels, there’s no reason to avoid coffee, tea, or red wine.

This article first appeared in the February 2008 issue of Consumer Reports On Health.