According to Andrew Weil, M.D., the craving for ice is linked to pregnancy and iron deficiency anemia. It's less frequently linked to a few other nutritional problems. The craving for or compulsion to chew ice is known as pagophagia.
Dr. Weil explains that studies show that people who are iron deficient tend to want to chew ice because they enjoy the taste more than those who do not have an iron deficiency. Studies also show that ice is beneficial in relieving the pain of glossitis, a tongue inflammation that appears with iron deficiency. Craving crushed ice is a symptom of pica, an eating disorder that can result from stress and from obsessive-compulsive disorder. Iron supplementation is only implemented if medical tests confirm the existence of an iron deficiency.