Chewing ice is a specific form of pica, or the practice of eating nonfood items including metal or paper, and is frequently found to be a symptom of iron-deficiency anemia. Pica is particularly common among young women because anemia, or low levels of red blood cells, is often the result of blood loss, which premenopausal women experience with both menstruation and childbirth.
We don't understand why people with iron-deficiency anemia crave ice, but there's enough evidence to suggest that if you do, you should see your doctor for a blood test. If your iron levels are low due to iron deficiency, one simple solution is to start taking iron supplements, which should help your levels return to normal within one to six months. Talk to your doctor about which supplements are best for you. Once you've developed anemia, it's difficult to get enough iron from diet alone, but it's important to eat foods that are rich in iron, such as cereal, beans, tofu, pumpkin, and spinach. (Pica, by the way, is the Latin word for magpie, a bird known for gathering a large collection of objects to build its nest.)
—Andrew S. Artz, M.D., assistant professor of hematology at the University of Chicago and a board member of the National Anemia Action Council (NAAC)