A lot of alternative health sources promote bentonite clay for all kinds of proposed health benefits.
But is it safe for internal use?
This is something I wanted to know because I believe that I have received benefits from ingesting bentonite clay. But I also had concerns about the toxic metals (lead, arsenic, cadmium, mercury, aluminum, etc.) contained in the clay.
So what’s the dealio?
Bentonite Clay Reliably Reduces Heavy Metal Toxicity in Livestock
Clays of various sorts, including bentonite/montmoroillonite clays, are used in livestock feeds. As a result, there is a fair amount of research demonstrating the health effects of feeding clay to various non-human animals.
Why the interest in feeding clay to livestock? Because livestock operations have a major problem with mycotoxin contaminants in the feed.
Mycotoxins are kind of a big deal. They can cause major health problems in all animals, including humans.
In livestock operations, there are lots of disease states that are commonly produced by mycotoxins.
For that reason, the industry wants an inexpensive and effective solution. And clays provide at least part of the overall solution in this regard.
Incidentally, reducing mycotoxin load in humans is one of the potential benefits of consuming bentonite clay internally. But in this case, I am just interested in looking at heavy metal safety of consuming clay.
So what does the research say in this regard?
Turns out that the research consistently shows that consuming clays such as bentonite clay reduce heavy metal toxicity in a variety of animals.
For example, some researchers had the horrific idea to feed lead. They also fed some of the fish clay along with the lead. The fish with no clay had predictable lead toxicity symptoms and lead accumulation in their organs. But the fish fed the clay showed no signs of lead toxicity and they did not accumulate lead in their organs. 
In another study, the researchers had the also horrific idea of feeding aflatoxin (a mycotoxin) to chickens. They found that feeding clay prevented harm from the aflatoxin (which is a consistent finding in all animals). But in this study, they also decided to measure the levels of minerals in the chicken’s bones. They found that the birds fed clay had no reduction in calcium or phosphorus. However, they did have a significant reduction in lead, fluorine, and manganese. In other words, clay actually reduced stored heavy metals in the body.
In another study, the researchers simply fed pigs either their usual diet or a diet supplemented with clay. After 100 days they found that the pigs eating clay had massive reductions in stored lead in their bodies versus the other pigs. In other words, eating clay reduced heavy metal burden. 
Another study with sadistic researchers found that (not surprisingly) feeding cadmium had negative health effects in pigs. However, adding clay to their diets reduced the harm in the cadmium-fed pigs. And in pigs fed no additional cadmium, clay reduced body burdens of cadmium. In other words, clay seems to reduce cadmium as well as lead burdens. 
While I haven’t yet come across any research specific to mercury or arsenic in animals and the effects of feeding clay, I suspect that clay binds to and removes these metals as well. The reason for my suspicion in that bentonite clay is shown to bind to and remove these metals from water and acidic mediums. In fact, clay is used for water purification because of this property.
So Is Bentonite Clay Safe for Internal Use?
Despite the heavy metal content of bentonite clay, I believe that the evidence is fairly strong that it is safe for internal use.
I choose to use bentonite clay internally because I believe that I receive benefits. As I have written about many times, I have a fairly long history of health and digestive problems, and I believe that eating bentonite clay continues to help with my health and digestion.
I am not suggesting anybody else needs to eat clay. Nor am I suggesting that my decision about the safety of ingesting clay should be yours. I am merely giving you the information that I have found to be useful in making an informed decision for myself.
With that said, I do think that it is advisable to consume a clay that is produced for internal use. If a clay is not intended for internal use, it may have been processed with chemicals that have unknown effects in the body.
There are many quality clays available that are intended for internal use. I cannot tell you which is best. I think each likely has its own unique benefits.
I can tell you that the clay that I primarily use is one that comes from the Mohave desert in California. It’s the clay that I recommend in my book, How to Heal Cavities and Reverse Gum Disease Naturally. If you purchase from Earth’s Natural Clay, make sure you select the product that is labeled for internal use.
If you have questions about clay that you’d like me to write about in future posts, please let me know in the comments below.