Bentonite Clay - History, Uses, and Benefits
For those not adventurous enough to eat clay many cosmetic and skincare companies include bentonite clay to fight acne, absorb toxins, and improve skin complexion.
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The term "bentonite" refers to rocks coming from volcanic ash beds which form during a volcanic eruption. Once these solids and glassy particles cool a substance called "smectite" forms, which encompasses a variety of expandable clay minerals. Montmorillonite is the smectite most commonly used in products containing bentonite clay. 
The largest source of bentonite clay is found in Fort Benton, Wyoming due to the presence of multiple volcanoes.  The United States is responsible for 35% of the 10 billion tons of bentonite mined each year, followed by Greece, Italy, India, China, and Australia.  The term "montmorillonite" was inspired by Montmorillon, the region in France where bentonite clay was first discovered. 
While a portion of this clay is orally ingested or applied to the skin, the majority of this earth material is used in industrial and manufacturing settings.
Bentonite clay is classified as a healing clay, which for thousands of years were used to treat and heal skin infections. Two philosophers, Aristotle (384-322 B.C.) and Pliny the Elder (23 ? 79 A.D.), provided detailed accounts of ingestion mud found at the base of volcanoes to improve digestion and cure issues in the digestive tract. 
It is proposed that bentonite clay primarily works on three fronts: it's absorbent, adsorbent, and rich in minerals. Absorbency is a materials ability to easily soak up liquid whereas absorbency is a materials ability to absorb another material.
One tablespoon, 0.36 ounces, or 10.2 grams of bentonite clay provides over 6.93 grams of silica, 2.51 grams of aluminum silica, 1.32 grams of sodium chloride, 1.29 grams of potassium, 1.12 grams of protein, and 1.10 grams of calcium. It also provides trace amounts of iron, magnesium, chlorine, sodium, manganese, iodine, zinc, and copper. 
it's proposed that the metallic ions like silver, copper, and zinc found in bentonite clay are responsible for its antibacterial properties.  Given the laundry list of vitamins and minerals in bentonite clay it's no wonder people have been eating and applying this material to their skins for possible health benefits. let's now further explore the uses and benefits of bentonite clay.
Bentonite Clay UsesBentonite clay has a multitude of claimed health-promoting uses and is most commonly applied directly to the skin or orally consumed. Only a few of the uses for bentonite clay have any scientific evidence at all. If you decide to consume bentonite clay it is at your own risk and should preferably be under the careful supervision of your healthcare professional.
Geophagy is the ancient practice of eating earth materials containing clay minerals to elicit a general healing response as well as fight infection and inflammation in the gastrointestinal tract.  While the written accounts of philosophers from the B.C. and early A.D. time periods carry merit, there's minimal clinical evidence supporting the use of bentonite clay to treat digestive issues.
There is however strong support for bentonite clay's ability to absorb and decrease the harmful effects of aflatoxin, a toxic compound commonly found in corn and peanut crops.  There is also small amounts of evidence supporting its ability to regulate uric acid and thyroid levels as well as kill viruses and bacteria.
Topical application of bentonite clay has clinical support for its ability to heal skin infections, treat ulcers, and kill harmful bacteria. Bentonite clay is most commonly included in cosmetic products to absorb skin oils, toxins, impurities, and improve complexion.
Outside of the clinical setting people use bentonite clay for numerous purposes including but not limited to: 
- Heal skin conditions like eczema, dermatitis, and psoriasis
- Remove toxins through the skin when bentonite clay is added to a bath
- Improve oxygen flow to cell
- Optimize the body?s pH
- Purify water
- Decrease itchiness and swelling from bug bites and scrapes
- Improve digestion and induce bowel movements
- Decrease instances of constipation, irritable bowel syndrome, and nausea
- Increase immune system function
- Improve teeth and gum health when used as a tooth paste
- Act as a baby powder replacement
While bentonite clay looks attractive on paper it can be misused and cause several side effects, primarily when someone over ingests the material. A larger analysis of multiple studies and medical reports found that consuming over 200 grams of bentonite clay per day can prevent the proper absorption of iron, zinc, and potassium. 
In one instance doctors found the parents of a 3-year-old were forcing their daughter to orally consume and rectally administer bentonite clay to treat chronic constipation. These practices left the girl with not only more severe constipation but also caused vomiting, lethargy, weakness, and severe electrolyte imbalances. 
Thankfully the girl made a full recovery but this example illustrates the importance of consulting with a healthcare professional before attempt drastic at-home homeopathic treatment options.
The Food and Drug Administration (FDA) has never formally supported the oral ingestion of bentonite clay so there is no recommended daily intake. However, a quick web search will yield thousands of results with dosage recommendation.
One popular website promoting homeopathic and naturopathic treatment options recommends vigorously mixing ½ to 1 teaspoon of bentonite clay in water and drinking immediately or gargling with the clay for 30 to 60 seconds.  On teaspoon of bentonite clay is equivalent to approximately 3.5 grams.
Those looking for skin applications can apply mix ¼ cup of clay with water to create a paste, apply to the skin, let it sit and dry before washing it off.  Although the skin may absorb some of the minerals found in bentonite clay, the likelihood of experiencing toxicity symptoms is significantly lowered compared to oral consumption.
From the industrial standpoint bentonite is an important substance used to lubricate and cool cutting tools, decolorize mineral, vegetable, and animal oils, as well as clarify wine, liquor, cider, beer, and vinegar.  Even if you've never eaten or rubbed bentonite clay on to your skin, you've likely used a product which incorporated this earth material.
Bentonite Clay BenefitsBentonite's clay ability to absorb and decrease the toxic effects of aflatoxins has the largest body of clinical support compared to its other purported benefits. Aflatoxins are toxic byproducts produced by certain fungi in and of foods consumed by humans and feeds consumed by livestock.  In fact, excessive aflatoxin consumption from corn and peanut products may stunt childhood growth. 
Research suggests that products like NovaSil clay, which contains bentonite clay, protects humans and other animals from aflatoxins by decreasing its absorption in the gastrointestinal tract.  One study of 63 children between the ages of three and nine found that 750mg to 1,500mg of NovaSil consumed orally every day for 14 days significantly reduced the aflatoxin metabolite found in urine as compared to calcium carbonate placebo.  These findings appear promising for populations consuming high quantities of crops often riddled with aflatoxins.
To test the safety of bentonite clay consumption 50 males and female volunteers between the ages of 20 and 45 consumed either 1.5 grams or 3.0 grams of clay every day for 14 days. Less than 10% of volunteers reported side effects and those that did experience minor GI issues like abdominal pain, bloating, constipation, diarrhea, and flatulence.
To further verify the clay's safety researchers took blood samples and found that bentonite clay consumption does not negatively impact general blood measures, liver and kidney function, electrolytes, vitamins A and E, or minerals. 
While the United States Food and Drug Administration (FDA) does not approve bentonite clay for the prevention or treatment of toxicity due to excessive aflatoxin consumption, the European Commission has classified clay-based binders as generally recognized as safe (GRAS).  Low or moderate bentonite clay consumption may be safe over short-term periods of time but additional studies are needed to determine its long-term safety.
Bentonite clay appears to have regulatory effects on both thyroid function and uric acid levels in animal studies. Researchers gave rats with an overactive thyroid (hyperthyroidism) between 0.3 and 2.0 grams of bentonite clay per kilogram of bodyweight.
Dosages of 0.3 and 1.0 gram per kilogram of bodyweight significantly lowered the quantity of the thyroid hormone thyroxine whereas 0.6 and 2.0 grams per kilogram of body weight improved sleep and decreased spontaneous activity.  it's possible that bentonite clay's high absorbency rendered the excess thyroxine inert and unfunctional.
A small study on rats found that 500mg to 1,000mg of bentonite clay per kilogram of bodyweight significantly lowered uric acid levels absorbing excess uric acid in the bloodstream and preventing uric acid from being absorbed in the intestines.  These findings are extremely promising but sadly have not yet been studied in humans. One in five people has high uric acid levels, a condition which significantly increases of developing gout and kidney stones. 
Bentonite clay may offer faster relieve and more effective protection from these painful conditions compared to prescription medication.
In addition to the clinically studied benefits mentioned above bentonite clay exhibits antibacterial properties against popular bacterial strains including but not limited to E. coli, ESBL E. coli, S. enterica serovar Typhimurium, P. aeruginosa, and M. marinum and significantly reduces growth of S. aureus, PRSA, MRSA, and nonpathogenic M. smegmatis. 
This antibacterial research has almost exclusively been carried out in cell cultures in laboratories, but this doesn't mean the findings should be discounted. While eating bentonite clay does not sound appealing to me, it may offer benefits that could significantly reduce illness and disease across the globe.
References1) Williams, Lynda B., and Shelley E. Haydel. ?Evaluation of the Medicinal Use of Clay Minerals as Antibacterial Agents.? International geology review 52.7/8 (2010): 745?770. PMC. Web. Nov. 2016
2) Axe, Josh. "10 Proven Bentonite Clay Benefits and Uses." Dr. Axe, 2016, Accessed Nov. 2016.
3) Mitchell, Nicole J. et al. ?Short-Term Safety and Efficacy of Calcium Montmorillonite Clay (UPSN) in Children.? The American Journal of Tropical Medicine and Hygiene 91.4 (2014): 777?785. PMC. Web. Nov. 2016.
4) Bennett, A., and G. Stryjewski. "Severe Hypokalemia Caused by Oral and Rectal Administration of Bentonite in a Pediatric Patient." National Center for Biotechnology Information, Pediatr Emerg Care, July 2006, Accessed Nov. 2016.
5) Hosterman, J.W. and S.H. Patterson. 1992. Bentonite and Fuller's earth resources of the United States. U.S. Geological Survey Professional Paper 1522. United States Government Printing Office, Washington D.C., USA.
6) Aflatoxins: Occurrence and Health Risks. Cornell University Department of Animal Science, Cornell University, 10 Sept. 2015, Accessed Nov. 2016.
7) Wang, J. S., et al. "Short-term Safety Evaluation of Processed Calcium Montmorillonite Clay (NovaSil) in Humans." National Center for Biotechnology Information, Food Addit Contam, Mar. 2005, Accessed Nov. 2016.
8) Fowler, Justin, Wei Li, and Christopher Bailey. ?Effects of a Calcium Bentonite Clay in Diets Containing Aflatoxin When Measuring Liver Residues of Aflatoxin B1 in Starter Broiler Chicks.? Ed. Richard A. Manderville. Toxins 7.9 (2015): 3455?3464. PMC. Web. Nov. 2016.
9) Cai, Y., et al. "Montmorillonite Ameliorates Hyperthyroidism of Rats and Mice Attributed to Its Adsorptive Effect." National Center for Biotechnology Information, Eur J Pharmacol, Dec. 2006, Accessed Nov. 2016.
10) Ma, Z., et al. "Montmorillonite Adsorbs Uric Acid and Increases the Excretion of Uric Acid from the Intestinal Tract in Mice." National Center for Biotechnology Information, J Pharm Pharmacol, Nov. 2009, Accessed Nov. 2016.
11) High Uric Acid Level. Mayo Clinic, Mayo Foundation for Medical Education and Research, 12 Dec. 2015, Accessed Nov. 2016.
12) HAYDEL, SHELLEY E., CHRISTINE M. REMENIH, and LYNDA B. WILLIAMS. ?Broad-Spectrum in Vitro Antibacterial Activities of Clay Minerals against Antibiotic-Susceptible and Antibiotic-Resistant Bacterial Pathogens.? The Journal of antimicrobial chemotherapy 61.2 (2008): 353?361. PMC. Web. Nov. 2016.