A reader wrote to us because his wife wanted him to start “a diatomaceous earth routine” for his health—that is, eat “dirt.” He asked if there’s any evidence that this has benefits. Here’s our scoop on one of the latest health fads to rock the U.S.
Diatomaceous earth (DE, also known as diatomite) is a type of soft sedimentary rock composed of the fossilized remains of single-cell aquatic organisms called diatoms. These vast silica-rich deposits are mined, ground to a chalky white powder, and sold for various uses. Like soil, DE varies a lot in composition.
You may be familiar with DE as a natural pest control agent (against roaches, fleas, and more), which works by drying out the insects. Because of its abrasive properties (similar to pumice powder), it’s also found in some exfoliants, eye shadows, and other cosmetic and personal care products.
But it’s the use of food-grade DE as a sort of “food supplement” that has been getting attention lately. DE is being promoted for everything from improving blood cholesterol, energy level, mental clarity, and mood to curing arthritis, hemorrhoids, hypertension, cancer, vertigo, periodontal disease, back pain, insomnia, and obesity. It’s touted as a way to make your hair shiny, your nails tough, and your skin fresh-looking.
Proponents, who mix the powder with water or juice, believe its “scrubbing” action also acts as a colon cleanse and rids the body of intestinal parasites, viruses, drug residues, pesticides, and toxic metals that supposedly contribute to digestive and menstrual woes, among other ailments. There are no earthly limits, it seems, as to what this “dirt” can do.
A dearth of research
Besides the abundance of testimonials on websites selling or promoting DE, where do such far-out notions come from? According to a 2011 study in Poultry Science, DE has the potential to eliminate parasites in organic free-range hens. Another study a few years ago found that DE can help remove heavy metals from water. Neither involved people, however, so such findings are not necessarily applicable to humans.
The only published human study we found, published in the European Journal of Medical Research in 1998, reported that consuming DE three times a day for eight weeks was associated with improved cholesterol and triglyceride levels. But the study was very small and had no control group. The findings have not since been replicated.
Many of the supposed benefits of DE are attributed to its silica, the form that the mineral silicon takes when bound to oxygen. The National Academy of Sciences, which sets the Recommended Dietary Allowances for nutrients, states that a “functional role for silicon in humans has not yet been identified, although animal studies show that silicon may be involved in the formation of bone.” And as a 2013 review paper in the International Journal of Endocrinology noted, silicon improves bone quality and mineralization and has been associated with increased bone density.
Other papers hypothesize that decreased silicon in tissues may be linked to age-related degenerative disorders such as atherosclerosis—though the mechanisms of action are not clear.
According to the Natural Medicines Comprehensive Database, which evaluates complementary therapies, dietary silicon is possibly effective for improving bone strength (though higher amounts don’t seem to help postmenopausal women). There is insufficient evidence to rate the effectiveness of silicon for heart disease, digestive problems, hair loss, dementia, or anything else it’s promoted for.
Geophagia: What on Earth Is That?
Eating “dirt” (soil, clay, or earth) is hardly a new phenomenon. The practice, called geophagia, has existed for thousands of years, dating back to Hippocrates, though scientists continue to debate whether it has any adaptive functions.
On shaky ground
We don’t recommend swallowing diatomaceous earth for “detoxing” or any other purpose. Your intestines don’t need a scouring pad to stay healthy: The human body is marvelously efficient when it comes to self-cleaning and protection from damage.
And while research on silicon, especially for bone health, is promising, more studies are needed to determine what benefits it might have and what forms would be best (not all are well absorbed). In the meantime, there’s no evidence that people are not consuming enough silicon, which is found in many foods, including whole grains and cereals (like oats, brown rice, and barley) and certain fruits (like raisins and bananas) and vegetables (like green beans). Coffee, beer, and water are other major sources of silicon. The National Academy of Sciences maintains that there is “no justification for adding silicon to supplements.”
More concerns: Though food-grade DE is “generally recognized as safe” for use as a filter aide in food processing, it’s not regulated by the FDA as a food supplement, which means you really don’t know what you may be ingesting. Plus, some DE products are combined with other ingredients of questionable value and unknown safety.
Also see The Truth About Detox Diets.