Would you eat this? It might look like a crunchy new breakfast cereal, but it's a close-up of diatomaceous earth, the fossilized microscopic skeletons of diatoms.

Would you eat this? It might look like a crunchy new breakfast cereal, but it’s a close-up of diatomaceous earth, the fossilized microscopic skeletons of diatoms.

Diatoms are unicellular algae, one of the two major classes of the phytoplankton that constitute the bottom of the food chain in oceans and freshwater. Diatomaceous earth is a soft, siliceous sedimentary rock containing the fossilized skeletal remains of diatoms. It has been used as a bug killer: it is hypothesized that the sharp particles physically cut up the insects and also damage their waxy protective layer, causing dehydration. It is also used as an abrasive, a filter, an anticaking agent, and in various other industrial and agricultural applications. It contains silica, mainly in the form of amorphous silicon dioxide but with some crystalline silica. Silica is dangerous when inhaled, causing lung disease in workers exposed to silica dust. Silicosis is the most common occupational disease worldwide.

Those are the indisputable facts. So far, so good. Now for the unsupported claims. Diatomaceous earth is being sold as a dietary supplement and is being promoted as “one of the cheapest and most versatile health products on the market.” One of the red flags for quack remedies is the claim that the remedy works for a long list of disparate ailments. Another is that the claims are supported only by testimonials, not by scientific studies. Another is the claim that it “detoxifies.” And most of those who claim it works just happen to have their own brand that they want to sell you. Diatomaceous earth fits the bill, on all counts. But just because it walks like a duck doesn’t mean we can summarily dismiss it. To be fair, we must examine the claims and the evidence.

The health claims

Taken internally, it is said to help promote healthier hair, skin, nails, gums, bones, and joints; support healthy digestion, improve absorption of nutrients, regularize bowel movements, and detoxify the digestive system; strengthen cartilage and reduce joint pain; assist in weight loss; promote healthy cholesterol levels and blood pressure; and increase energy. It is said that it either does, “can,” or “might” have many other benefits: it functions like a medicine against cough; reduces inflammation in bronchitis; reduces the side effects of menopause; preserves youthfulness and delays aging; safeguards against radiation; acts as a diuretic; can prevent both diarrhea and constipation; can help normalize hemorrhoidal tissue; may alleviate back discomfort; can stimulate defense mechanisms; can decrease vertigo, headache, tinnitus and insomnia; might help prevent TB; might help with Alzheimer disease; can stimulate the cell metabolic process and division; and it “prolongs and slows down facial aging lines.”

It must be good, because it’s “natural” and it’s “organic.” I guess they justify calling it “organic” because it was derived from an organism, the diatom; but silicon dioxide is a mineral. It’s a rock, folks, a kind of sand.

Some of the language of the claims is incoherent. It “proves to be effective with female discharge, abscesses and stomach problems within the vagina and cervix, in addition to mastitis (specifically for breastfeeding moms).” Really? Where is that proof? And how can you have stomach problems within the vagina? It “might help diabetes by marketing synthesis of elastase inhibitor through the pancreas.” It “might help arterial disease by strengthening the bloodstream ships.” Hmmm…

On one website they claim that diatomaceous earth has a strong negative charge and that pathogens and toxins have a positive charge; I question that. They claim that it attracts, traps, and absorbs fungi, protozoa, viruses, endotoxins, pesticides, drug residues, E.coli, and heavy metals. Apparently it’s pretty smart; somehow it knows to only attract things that are bad for you. They say the sharp particles scrub the walls of the intestines. They say the colon is coated with mucus and molds and that removing the coating allows better absorption of nutrients. Really? I would think sharp particles would injure the delicate lining of the bowel; mucus is normal and has a protective function; molds are not a problem except in the imagination of those who believe in Candida overgrowth syndrome; and if anything, I would think diatomaceous earth would be more likely to absorb nutrients and decrease their availability.

On another page of that same website they claim “life can’t exist without silica,” “silica is the most important trace element in human health,” and “most people are silica deficient” and they make extravagant claims for its health benefits. Their evidence is from testimonials, and they make excuses:

Of course, most actual in depth health related studies are initiated and controlled by the pharmaceutical industry, and why should those companies study the value of health remedies found in nature that could actually hurt their bottom line?

And they protest that they are not allowed to make specific medical claims, and are required to use the term “may help.” This is a deceptive ploy to make customers think their product is truly effective and it is only unfair censorship that prevents them from saying so.

The scientific evidence

Natural medicine websites claim that silicon is an essential trace mineral, that our diet fails to provide the amount we need, that there is a deficiency syndrome, that our soils have been depleted of silicon, and that supplementation has significant health benefits. More reliable science-based sources indicate that it has not been established that silicon has any metabolic function, and it is not considered to be an essential trace element.

Silicon is readily available from foods, and “neither silicon deficiency nor a silicon-responsive condition have yet been identified in humans.” There is some preliminary evidence suggesting that silicon might have a role in bone health, but that has not been confirmed.

PubMed lists 92 articles on diatomaceous earth, but none of them support the health claims that have been made. A PubMed search for the health benefits of silicon was equally unrewarding. One article found a decrease in litter pH when silicon was added to the feed of turkeys; nice to know! One review article said “compelling data [compelling to whom?] suggest that silica is essential for health although no RDI has been established.”

Another review found a positive relationship between dietary silicon intake and bone regeneration. A review of the skeletal effects of nutrients concluded, “Data are very limited for the role of nutritional levels of boron, strontium, silicon and phosphorus in bone health. A nutrient rich diet with adequate fruits and vegetables will generally meet skeletal needs in healthy individuals.” As far as I was able to determine, there have never been ANY controlled clinical trials in humans to test the effects of supplementing the diet with silicon or diatomaceous earth.

One evidence-based nutrition website concluded that the “claims of health benefits are theoretical and anecdotal” and that “while some supplements can definitely help, there is absolutely no evidence that diatomaceous earth is one of them.”

The Natural Medicines Comprehensive Database doesn’t take diatomaceous earth seriously enough to even list it. It does list silica, which it rates as “likely safe” but recommends against using it during pregnancy and lactation. It rates silica as “possibly effective for osteoporosis.” It found some evidence that men and premenopausal women who have higher dietary intake of silicon seem to have higher bone mineral density, which could reduce the risk of osteoporosis. But higher silicon intake does not seem to benefit postmenopausal women; bone loss in postmenopausal women is primarily due to bone resorption, and silicon seems to affect only bone formation. They found insufficient reliable evidence to rate the effectiveness of silicon for any of its other proposed uses. They stated that “an essential biological role for it has not been identified.”

No thank you!

Is it worth trying? I can’t rule out the possibility that it might work for some indications, but without proper controlled clinical studies we have no way of knowing. I can’t prove that it doesn’t work or that it is unsafe, but in my opinion there is no credible basis for recommending dietary supplementation with diatomaceous earth. Taking it would amount to offering yourself as a guinea pig in an uncontrolled experiment and sandpapering your intestines with an industrial abrasive on the strength of testimonials. I’ll pass.

Posted by Harriet Hall

Harriet Hall, MD also known as The SkepDoc, is a retired family physician who writes about pseudoscience and questionable medical practices. She received her BA and MD from the University of Washington, did her internship in the Air Force (the second female ever to do so),  and was the first female graduate of the Air Force family practice residency at Eglin Air Force Base. During a long career as an Air Force physician, she held various positions from flight surgeon to DBMS (Director of Base Medical Services) and did everything from delivering babies to taking the controls of a B-52. She retired with the rank of Colonel.  In 2008 she published her memoirs, Women Aren't Supposed to Fly.