Re:

Silicon in the form of silicates being the most abundant element in the earth's crust, its easy to imagine that people who eat home-grown vegetables , or those not mechanically cleaned or peeled consistently would have no problem receiving adequate silica, unless they are foolish enough to brute force clean everything Felix Unger style. This of course means that those who have relied on grocer store foods haven't reaped the benefits of those tiny amounts of dirt, to their own detriment.