Plant enzymes are essential for the proper digestion of food. According to Howard F. Loomis, Jr., D.C., of Forsyth, Missouri, the ability to absorb the nutrients in the food we eat is at the foundation of good health. If we treat digestive disorders, other complaints often clear up as a result. In his practice, Dr. Loomis tests his patients for enzyme deficiency and then replenishes this deficiency with enzyme supplements. Dr. Loomis adds, if a patient is eating a diet of junk food, all the enzymes in the world won't improve his basic health. Enzyme therapy needs to be combined with good eating habits. Fresh fruits, vegetables, nuts, and seeds can provide plentiful plant enzymes, and plant enzyme supplements are only meant to supplement those that naturally occur in food.

  Plant enzyme therapy uses all four categories of plant enzymes: 

1. protease digests protein; 

2. amylase digests carbohydrates; 

3. lipase digests fat;

4. cellulase digests fiber.

  The human body is unable to produce cellulase, therefore plants are a person's only source of it. Numerous plant enzyme formulations on the market combine these enzymes.

   In the 1920s Dr. Howell and first proposed the phenomenon of predigesting the food by plant enzymes. He stated, if the stomach is performing its proper role, and we are eating our foods uncooked, a large portion of the intake will be partially digested before reacting with the stronger digestive juices found there. Moreover, fewer of your body's internal digestive enzymes will be called upon to perform the digestive function. It is this easing of the body enzymes' workload that is thought to contribute substantially to the healing effects of enzyme therapy. According to Dr. Howell, when the body receives plentiful supplies of enzymes, its internal enzyme supplies are preserved for the important work of maintaining metabolic harmony. As a result, many body systems are strengthened.

  This predigestion of food happens during an interim period, before enough hydrochloric acid (HCl) accumulates in the stomach to begin the next stage in digestion, but this is not commonly known. Lita Lee, Ph.D., of Eugene, Oregon, states that many people don't believe this because they are told that gastric HCl excreted by the stomach destroys the enzymes. Actually, it takes thirty to sixty minutes before enough HCl accumulates in the stomach to initiate the digestion of food. Further, HCl does not destroy but merely deactivates these enzymes by making the environment more acidic. They are reactivated later in the duodenum (upper segment of the small intestine) if the optimum, more alkaline pH is achieved. Enzymes in the stomach can digest 30 percent to 40 percent of the starches we eat. Dr. Lee says that by eating raw foods and taking food enzymes, 30 percent of the protein and 10 percent of the fat can be digested in the stomach in less than one hour.

  Cooking food can destroy these important plant enzymes. They are more heat-sensitive than vitamins and are the first to be destroyed during cooking. They are destroyed by being heated above 118 degrees Fahrenheit. Dr. Lee points out, thay are deactivated or destroyed by pasteurizing, canning, and microwaving. However, while raw foods are recommended, a 100 percent raw foods diet is not necessary. Dr. Loomis points out that some people may have problems digesting uncooked food because of a lack of cellulase. He says, people who rarely eat raw food can have problems when they finally eat uncooked fruits and vegetables because they don't chew their food thoroughly. Chewing liberates the cellulase out of the food, but when they eat the raw food and don't chew properly the cellulase is never released. Cellulase may also be lacking because of the way the food was handled by the suppliers. Some supermarket vegetables are missing cellulase because they have been sprayed with sulfites which can destroy these enzymes.