Does the decay of Carbon-14 effect health in biological systems?
I mean take a glucose molecule C6H12O6, suddenly one of the Carbon atoms randomly decays to a Nitrogen atom. Does this molecule continue to function as a glucose molecule ? This question extends to every molecule in the body that contains Carbon atoms.

To answer this part of the question, obviously a glucose molecule which has had a carbon-14 atom decay isn't a glucose molecule anymore. What the glucose molecule turns into is anybody's guess, but no doubt there would be a wide range of molecular fragments from the multiple decays of glucose molecules. Some of the molecular fragments would be highly reactive and cause unusual reactions within our bodies.
Worse, the cabon-14 emits a beta particle when it decays. It would be sort of like a bullet ripping through the body. Thus the beta particle would disrupt the bonding in other molecules, not just in the original glucose molecule.