A pharmacological level where the nutrients forcefully stimulates a biological or neuroendocrine pathway. And a toxicological level where the substance is in excess and overwhelms or poisons the cells or biological systems. A nutrient that is deficient may cause a toxic reaction upon introduction to the system. The nutrient must be introduced at homeopathic levels and then increased in dose until a physiological or pharmacological dose is obtained. Nutrients that are no longer required will produce a toxicological effect.
Some nutrients enhance the parasympathetic nervous system others enhance the sympathetic branch.
Nutrients can also be antagonistic to both of these parts of the nervous system. Synergistic nutrients can enhance the actions and the storage of each other while antagonistic nutrients detract from the actions and storage of each other. Any nutrient if taken in excess can create a deficiency of nutrients that they naturally antagonize. The nutrient must be increased from a very low dose to a therapeutic very gradually. Any substance that is non-toxic may produce a toxic reaction if the biological system is toxic or disordered.