Theories as to why some people crave or eat dirt include nutritional deficiencies, malnutrition, poverty, mental illness, cultural factors and pregnancy, according to Kids Health. Some people who eat dirt say they like the taste or texture, and for others it is a reaction to stress. Geophagia, or eating dirt or clay, is one form of an eating disorder called pica.
Some researchers think geophasia may not be an abnormal behavior but beneficial in some way by providing people with vital minerals and inactivating toxins, claims Scientific American. At the same time, eating dirt can interfere with mineral absorption causing iron and other nutrient deficiency. Eating dirt can also cause lead poisoning and parasitic or other infections, says KidsHealth.
Another explanation for eating dirt is that it is a form of detoxification, according to Scientific American. Scientists hypothesize that when people eat clay, the negatively charged clay molecules adhere to positively charged toxins in the digestive system and carry them out of the body. Evidence to support this so far only comes from animal studies. The scientists who support this hypothesis believe that, in most cases, eating dirt is not a sign of mental illness. If dirt eating is causing problems, a doctor can manage the behavior, says Kids Health.