Antagonism is, excess intake of a single element can decrease the intestinal absorption of another element. As an example, a high intake of calcium depresses intestinal zinc absorption, while an excess intake of zinc can depress copper absorption. These antagonistic minerals are often ions with the same charge, they share same metal transporters in intestine and therefore cause the competition for absorption.
How to reduce the antagonism? Dietary levels and ratios of trace minerals must be reasonable. Secondly, adopt organically bound minerals, for example chelates, competition for absorption can be avoided by using the pathway of the organic ligands.