system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is chewing on ice thought to be a symptom of iron deficiency or anemia?
gpt
Its thought that chewing ice in anemics sends blood rushing to the brain, making them more alert. Pica (craving/chewing things that aren't food or otherwise have no nutritional value) is linked to an iron deficiency - its not totally clear why for some substances.