Cold brew is delicious and all, but often the best part about sipping on iced coffee in the summer is having a big cup of ice to chew on afterwards. If you're sitting at your desk or stuck in the car, chewing on ice gives you an activity.
You funnel the ice chips into your mouth, wait for them to melt slightly, and then gnaw down for a few seconds. Afterwards, you feel hydrated, cool, and maybe even more alert — despite getting dirty looks from your desk mate for making so much noise. But is your weird penchant for chewing on ice the sign of a more serious medical condition? Maybe.
The medical term for craving non-food items like ice, clay, soil, and paper (yes, really) is "pica." It's unclear exactly what leads people to want to eat these random items, but some of it may have to do with having certain nutritional deficiencies. Wanting to chew ice, for example, is a type of pica called "pagophagia," and it may be a red flag that someone has anemia.
People with anemia lack iron, which your body needs to produce hemoglobin, a protein in red blood cells that carries oxygen, explains Melissa Hunt, PhD, associate director of clinical training in the Department of Psychology at University of Pennsylvania, who has studied pagophagia. If your hemoglobin gets low, then your blood can't carry oxygen to your brain, she says. This is why one symptom of anemia is feeling sluggish or tired. "In anemic people, chewing ice increases oxygen in the brain, resulting in a feeling of greater alertness," she says. (Interestingly, there's also a huge link between iron deficiency and restless leg syndrome, a neurological condition defined by an irresistible urge to move the legs.) So, it feels good to chomp on ice simply because the action improves blood flow to the brain.
A 2014 study conducted by Dr. Hunt showed that giving anemic people ice to chew can significantly improve their performance on tests. But in people who aren't anemic, the increased blood flow probably isn't noticeable, "because their brains are getting plenty of oxygen all the time," Dr. Hunt says. "Increasing oxygen doesn't matter if you're already getting enough."
If you are someone who craves ice frequently, and you experience other symptoms of anemia (like fatigue, weakness, and shortness of breath), then it's worth it to discuss with your doctor. "Most people who crave ice turn out to be anemic," Dr. Hunt says. Luckily, iron deficiency anemia is pretty easy to treat with iron supplements, and usually when people's iron levels are restored, the urge to chew ice goes away, too. Beyond anemia, it's possible that pica can be linked with stress, obsessive-compulsive disorder, or a developmental disorder, in which case, therapy can be helpful. But only your doctor or healthcare provider can help you figure out what the underlying cause is.
At the end of the day, while your ice-chewing habit might be just another part of your morning routine, it's important to pay attention to your cravings. And if chewing ice really is just something you do to pass the time, perhaps you should consider another fidgety hobby that's quieter and better for your teeth.