Is Clay Eating Dangerous?
Some fasting and detoxification programs recommend the ingestion of clay to bind toxins in the intestines. Given a reader’s recent comment, I’ve looked a little harder for reports in the medical literature claiming benefit or harm from clay eating.
While polychlorinated biphenyls (PCBs) bind to clay in the environment (WHO, 2003) and ingested clay can prevent aflatoxin absorption and toxicity in animals and humans (Toxicological Sciences 52:118, 1999), there is limited data about the capacity of clay to adsorb other toxins in the human intestine. Polyaromatic hydrocarbon body levels were not affected by ingesting clay in one small study of humans in Ghana. In animals, attempts to block the absorption of locoweed to prevent toxicity failed (J. Animal Science 75:1867, 1997).
Hazards of clay ingestion have been reported. These include intestinal obstruction (Archives de Pediatrie 11: 461, 2004), ruptured intestines (Acta Chir. Belg. 99: 130, 1999), near-fatal low potassium levels (Ob. Gyn. 102: 1169, 2003), and toxacara roundworm infection (South. Med. J. 91: 882, 1998; Southeast Asia Journal of Tropical Medicine 34: 7, 2003; Brazil Curr. Op. Ophth. 12: 450, 2001; in Trinidad TRS Trop Med 96:139, 2002).
Eating clay was found to produce clinical mercury poisoning (Conn. Med. 61: 207, 1997) and lead poisoning (Clin. Ped. 43: 189, 2004; Amb. Ped. 3: 37, 2003). Effectively, it caused heavy metal toxicity rather than protected against it. There’s little assurance that commercial preparations of clay are devoid of these toxins.
So, I’ll answer this one in the affirmative. Eating clay harvested straight from the earth or taking clay (or bentonite) tablets without checking for impurities can be dangerous. Although I don’t recommend it, if you choose to make clay ingestion a part of your detox program, know the source and the method. For everyone, but especially if you have a history of previous abdominal or bowel surgery, be cautious regarding amount as the intraluminal swelling and hardening of ingested clay (body heat acting as a kiln) can lead to obstructions and subsequent bowel rupture – or surgery as a prevention against bowel rupture. Avoid clay enemas and be sure to ingest plenty of electrolytes.