Abstract: A method for preparing an element-rich composition for use as supplement in biological or physiological systems, comprising subjecting fly ash to the influence of reactants capable of dissolving a plurality of the components of the fly ash into a biologically assimilable form selected from chelates, complexes and lactic acid salts and obtaining the biologically assimilable form of the fly ash, and an element-rich composition prepared according to this method, the use of said element-rich composition as source of elements for animal and human consumption and in processes in which one or more elements, including trace elements, are essential.