Oxalsyre (som findes i spinat og rabarber) og fytinsyre (som findes i kornprodukter) kan hæmme calciumabsorptionen ved at danne uopløselige forbindelser med calciumioner.
Oxalic acid (found in spinach and rhubarb) and phytic acid (found in whole cereals) may inhibit calcium absorption through formation of insoluble compounds with calcium ions.