DENutrients: Cancer Causing?

The common misconception of diatomaceous earth being carcinogenic.

Crystalline Silica and Amorphous Silica

In my website, I’ve already mentioned a few times that there are different types of diatomaceous earth grades.

Food-Grade quality is where it is mined raw and dried at relatively low or ambient temperatures. These are mainly made up of amorphous silica, which is safe, but may contain a small percentage of naturally occurring crystalline silica, usually less than 1%.

Calcined Grade aka Pool-Grade undergo a process known as Calcining. It exposes them to high temperatures of up to 1000°C, thus physically transforming into cristobalite. It can contain up to 40% crystalline silica. Flux-Calcined is also done similarly but with added fluxing agent to fuse the diatoms, the crystalline silica can go up to 70%.

Remember that crystalline silica is the one you want to AVOID. It is toxic and classified as a human lung carcinogen by OSHA.

Crystalline Silica

Although crystalline silica is classified as a carcinogen, you will be surprised to know that this mineral is among the most abundant minerals in the world! And comprises over 12% of the earth’s crust. They are found in rock, sand, soil, pottery, and even your marble or quartz tabletop.

Health Effects of Crystalline Silica

There are some studies to show that massive quantity exposure and prolonged inhalation of crystalline silica are associated to the damage of respiratory system, silicosis and cancer. These are usually related to high-risk workers such as miners and construction workers.

Did you know that wood dust is classified as Class 1 carcinogen by IARC (International Agency for Research on Cancer) ?

Is DENutrients Diatomaceous Earth safe?

Our diatomaceous earth is amorphous silica, and has less than 0.5% of crystalline silica which is naturally formed by volcanic lava formation. After all, these are fossilised algae!

Amorphous silica is used widely in our food, cosmetics and pharmaceutical industry. These products include rice grains, facial cleansers, body scrubs, pet litter, art clay, wine/beer filtration, etc.

Diatomaceous earth is a Class 3 Carcinogen

Do not panic when you read “Class 3 carcinogen”, diatomaceous earth is classified as a class 3 carcinogen by IARC. A class 3 listing indicates that diatomaceous earth is not classifiable as carcinogenic to humans, since there are no conclusive and definitive research to date. And this is only applicable for diatomaceous earth with less than 1% of crystalline silica content.

Research Studies

As mentioned earlier, that there are no conclusive research studies that concludes diatomaceous earth is carcinogenic to humans. There are many research studies done on mice. It is to be noted that these experiments are done in excessive quantities that is not achievable in practical situation. And most of these studies concluded that crystalline silica has exhibit genotoxic effects in cells after exposure to crystalline silica but not amorphous silica.

If you are keen, you can use this allometric scaling calculator ( to convert the dosage in the study done on mice/rabbits to humans. However, do note that some studies are done in mg/m3 and may not be able to convert into weight.

More Information

These are extracted from NPIC (National Pesticide Information Center) website.

What happens to diatomaceous earth when it enters the body?

When diatomaceous earth is eaten, very little is absorbed into the body. The remaining portion is rapidly excreted. Small amounts of silica are normally present in all body tissues, and it is normal to find silicon dioxide in urine. In one study, people ate a few grams of diatomaceous earth. The amount of silicon dioxide in their urine was unchanged.

After inhalation of amorphous diatomaceous earth, it is rapidly eliminated from lung tissue. However, crystalline diatomaceous earth is much smaller, and it may accumulate in lung tissue and lymph nodes. Very low levels of crystalline diatomaceous earth may be found in pesticide products.

Is diatomaceous earth likely to contribute to the development of cancer?

When mice were forced to breathe diatomaceous earth for one hour each day for a year, there was an increase in lung cancers. When rats were fed silica at a high dose for two years, there was no increase in cancer development.

Most diatomaceous earth is made of amorphous silicon dioxide. However, it can contain very low levels of crystalline silicon dioxide. Amorphous diatomaceous earth has not been associated with any cancers in people.

Has anyone studied non-cancer effects from long-term exposure to diatomaceous earth?

In a rabbit study, researchers found no health effects after applying diatomaceous earth to the rabbits’ skin five times per week for three weeks. In a rat study, researchers fed rats high doses of diatomaceous earth for six months. They found no reproductive or developmental effects. In another rat study, the only effect was more rapid weight gain. That study involved 90 days of feeding rats with a diet made of 5% diatomaceous earth.

When guinea pigs were forced to breathe air containing diatomaceous earth for 2 years, there was slightly more connective tissue in their lungs. When researchers checked before the 2-year mark, no effects were found.

A very small amount of crystalline diatomaceous earth may be found in pesticide products. Long-term inhalation of the crystalline form is associated with silicosis, chronic bronchitis, and other respiratory problems. The bulk of diatomaceous earth is amorphous, not crystalline. The amorphous form is only associated with mild, reversible lung inflammation.

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