The fossilised Diatoms contain a number of nutritional metal elements, as well as some heavy metals such as Aluminium, albeit in the Oxide form that is non-toxic (as do many other beneficial mineral clays and soil products) - and it is insoluble in any case and not likely to come of out the fossil matrix.www.earthworkshealth.com/human-use.phpA typical dosage for human consumption of food-grade DE