Every function in the body requires enzymes, which occur naturally in both plants and animals.
The possible need for enzyme supplements in the modern American diet is a direct result of our affinity for cooked and processed foods, in which the natural enzymes of both have been either partially or entirely destroyed.
Every raw whole food comes with its own complete set of enzymes to aid in its digestion in the body but, when brought above a certain temperature or exposed to additives or irradiation, these whole food enzymes are ruined, often leaving our bodies with significant amounts of undigested food, chemicals and nutrients to pass on to excretion.
For those whose diets may be lacking a natural intake of enzymes, a supplement may help support overall health.