Earthworks wrote: Not to worry about taking too much - any excess silica not needed by the body is naturally eliminated through the kidneys and intestines... but we must find our own comfortable levels.
I don't think silica is very soluble, so not much going out via the kidneys. Most things ingested that are not absorbed are eliminated via the intestines.
Wikipedia wrote:Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae. It is used as a filtration aid, mild abrasive in products including toothpaste, mechanical insecticide, absorbent for liquids, matting agent for coatings, reinforcing filler in plastics and rubber, anti-block in plastic films, porous support for chemical catalysts, cat litter, activator in blood clotting studies, a stabilizing component of dynamite, and a thermal insulator.
Sounds delicious
The reason that we have diatomaceous earth deposits is that the stuff is not soluble, so it accumulated in vast deposits on the sea floor. Same thing with calcium carbonate (limestone), calcium phosphate, and a host of other biominerals.
As an insecticide DE is probably fine, relatively non-toxic when used properly, and probably mildly effective.
However, what is the mechanism of action in promoting human health? How is eating very, very small pieces of glass supposed to be healthful?