My first experience with the concept of nutritional deficiency came indirectly during a biochemistry class while at University. We were studying enzyme kinetics which is the study of the rates of chemical reactions that are catalyzed by enzymes.

In simple terms my professor was explaining that an enzyme reaches peak efficiency (or Vmax) when there is enough substrate, or raw material, for it to act on.

Referenced from http://en.wikipedia.org/wiki/File:Michaelis-Menten_saturation_curve_of_an_enzyme_reaction.svg

We then examined a human enzyme that required a cofactor, in this case magnesium, in order to function. Even when completely saturated with substrate this enzyme would not function without its cofactor. In fact the reaction would reach its peak efficiency only when a minimum concentration of magnesium was added to the reaction.

Our professor then made a comment that would forever change my life. He said you might want to go out and get magnesium, but you get all you need in your food. It didn’t happen in that moment, but over the next couple of days the nagging question surfaced in my consciousness. What if you don’t get all you need in your food?