It is disclosed here a method for reducing phosphate absorption in a human or non-human animal subject wherein the subject consumes a diet containing phytic acid or phytate and either has or is at risk of developing hyperphosphatemia. The method includes the step of administering orally to the subject an anti-phytic acid (C6H6[OPO(OH)2]o) antibody or an anti-phytate antibody in an amount effective to reduce or maintain the serum phosphate concentration in the subject.