The pharmaceutical industry tends to study drugs in isolation. What we need is better understand of the interaction of drugs.

So each of the medicines affect the metabolism of iron. Malaria also likes iron. So the drugs in combination counter act each other.

BTW: You probably should change the line that begins with

Vitamin C is an element

I realize you are using "element" as a generic pronoun which is fine in casual converation, but the term "element" has a specific meaning in chemistry.

I don't know the best classification for vitamin C. People often refer to it as a nutrient or a chemical compound.

!WINE