Clark also recommends cooking in iron pans, as food can derive iron from the pan during the cooking process. "The iron content of tomato sauce cooked in an iron pot for three hours showed a striking increase, the level going up nearly 30 times," she writes. And people who are likely to have low iron should avoid drinking coffee or tea with meals, she says, since substances in these drinks can interfere with iron being absorbed into the body. "Active women need to be a lot more careful about their food choices," sums up Purdue's Lyle. "If you pay attention to warning signs before iron reserves are gone, you can remedy the deficiency before it really becomes a problem."