It doesn't matter which it is, the same answer is there for the healthy to stay healthy and the sick to heal. For what enzymes are and what they can do please really read this page. Then take my word for it.
All health starts in the stomach with digestion.
If you have any problems whatsoever with digestion, from heartburn to gas, you probably need enzymes. If you have heartburn you may need something called MSG but that is another subject. You can ask your doctor about that. Your body doesn't have an unlimited ability to supply. You use up reserves when you eat cooked foods rather than raw.