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. (more…)