WHAT ARE ENZYMES? The late Dr. Edward Howell, a physician and pioneer in enzyme research, called enzymes the "sparks of life." These energized protein molecules play a necessary role in virtually all of the biochemical activities that go on in the body. They are essential for digesting food, for stimulating the brain, for providing cellular energy, and for repairing all tissues, organs, and cells. Life as we know it could not exist without the action of enzymes, even in the presence of sufficient amounts of vitamins, minerals, water, and other nutrients. In their primary role, enzymes are catalysts—substances that accelerate and precipitate the hundreds of thousands of biochemical reactions in the body that control life's processes. If it were not for the catalytic action of enzymes, most of these reactions would take place far too slowly to sustain life. Enzymes are not consumed in the reactions they facilitate. Each enzyme has a specific function in the body that no other enzyme can fulfil. The chemical shape of each enzyme is specialized so that it can initiate a reaction only in a certain substance, or in a group of closely related chemical substances, and not in others. The substance on which an enzyme acts is called the substrate. Because there must be a different enzyme for every substrate, the body must produce a great number of different enzymes. THE FUNCTIONS OF ENZYMES Enzymes assist in practically all bodily functions. Digestive enzymes break down food particles for storage in the liver or muscles. This stored energy is later converted by other enzymes for use by the body when necessary. Iron is concentrated in the blood by the action of enzymes; other enzymes in the blood help the blood to coagulate in order to stop bleeding. Uricolytic enzymes catalyze the conversion of uric acid into urea. Respiratory enzymes facilitate the elimination of carbon dioxide from the lungs. Enzymes assist the kidneys, liver, lungs, colon, and skin in removing wastes and toxins from the body. Enzymes also utilize the nutrients ingested by the body to construct new muscle tissue, nerve cells, bone, skin, and glandular tissue. One enzyme can take dietary phosphorus and convert it into bone. Enzymes prompt the oxidation of glucose, which creates energy for the cells. Enzymes also protect the blood from dangerous waste materials by converting these substances to forms that are easily eliminated by the body. Indeed, the functions of enzymes are so many and so diverse that it would be impossible to name them all. Enzymes are often divided into two groups: digestive enzymes and metabolic enzymes. Digestive enzymes are secreted along the gastrointestinal tract and break down foods, enabling the nutrients to be absorbed into the bloodstream for use in various bodily functions. There are three main categories of digestive enzymes: amylase, pro tease, and lipase. Amylase, found in saliva and in the pancreatic and intestinal juices, breaks down carbohydrates. Different types of amylase break down specific types of sugars. For example, lactase breaks down milk sugar (lactose), maltase breaks down malt sugar (maltose), and sucrose breaks down cane and beet sugar (sucrose). Protease, found in the stomach juices and also in the pancreatic and intestinal juices, helps to digest protein. Lipase, found in the stomach and pancreatic juices, and also present in fats in foods, aids in fat digestion. Metabolic enzymes are those enzymes that catalyze the various chemical reactions within the cells, such as energy production and detoxification. All of the body's organs, tissues, and cells are run by the metabolic enzymes. They are the workers that build the body from proteins, carbohydrates and fats. Metabolic enzymes are found in the blood, organs, and tissues doing their specific work. Each body tissue has its own specific set of metabolic enzymes. Two particularly important metabolic enzymes are su-peroxide dismutase (SOD) and its partner, catalase. SOD is an antioxidant that protects the cells by attacking a common free radical, superoxide. Catalase breaks down hydrogen peroxide, a metabolic waste product, and liberates oxygen for the body to use. FOOD ENZYMES While the body manufactures a supply of enzymes, it can also obtain enzymes from food. Unfortunately, enzymes are extremely sensitive to heat. Even low to moderate heat (118°F or above) destroys most enzymes in food, so to obtain enzymes from the diet, one must eat raw foods. Eating raw foods or, alternatively, taking enzyme supplements, helps prevent depletion of the body's own enzymes and thus reduce the stress on the body. Enzymes can be found in many different foods, from both plant and animal sources. Avocados, papayas, pineapples, bananas, and mangos are all high in enzymes. Sprouts are the richest source. Unripe papaya and pineapple are excellent sources of enzymes. The enzymes extracted from papaya and pineapple—papain and bromelain, respectively—are proteolytic enzymes. Many fat-containing foods also supply lipase, which breaks down fats. In fact, fat in food exposed only to pancreatic lipase (the lipase produced by the body) in the intestines is not as well digested as fat that is first worked on in the stomach by food lipase. Pancreatic lipase digests fat in a highly alkaline environment (the intestines), whereas lipase found in food fats works in a more acidic environment (the stomach). The optimal extraction of nutrients from fats depends on the work of different fat-digesting enzymes in successive stages. Superoxide dismutase occurs naturally in a variety of food sources, including barley grass, broccoli, Brussels sprouts, cabbage, wheatgrass, and most green plants. COMMERCIALLY AVAILABLE ENZYMES The majority of commercially available enzymes are digestive enzymes extracted from various sources. (Scientists are unable to manufacture enzymes synthetically.) Most commercial enzyme products are made from animal enzymes, such as pancreatin and pepsin, which help in the digestion of food once it has reached the lower stomach and the intestinal tract. Some companies make their supplements from enzymes extracted from aspergillus, a type of fungus. These enzymes begin their predigestive work in the upper stomach. All of these products are used primarily to aid the digestion of foods and absorption of nutrients, especially protein. Proteolytic enzymes available in supplement form include pepsin, trypsin, rennin, pancreatin, and chymotryp-sin. In addition to aiding digestion, proteolytic enzymes have been shown to be beneficial as anti-inflammatory agents. Pancreatin, derived from secretions of animal pancreas, is a focus of cancer research, because people with cancer are often deficient in this enzyme. Pancreatin is used in the treatment of pancreatic insufficiency, cystic fibrosis, digestive problems, food allergies, autoimmune disorders, viral infections, and sports injuries. Also available in supplement form are the antioxidant enzymes superoxide dismutase (SOD) and catalase. WHAT'S ON THE SHELVES Enzymes are available over the counter in tablet, capsule, powder, and liquid forms. They may be sold in combination with each other or as separate items. Some enzyme products also contain garlic to help digestion. For maximum benefit, any digestive enzyme supplement you choose should contain all of the major enzyme groups—amylase, protease, and lipase. Digestive enzymes should be taken after meals, unless you are eating processed and/or cooked foods, in which case it is best to take them during the meal. You can make your own digestive enzymes by drying papaya seeds, placing them in a pepper grinder, and sprinkling them on your foods. These have a peppery taste. If you take supplemental superoxide dismutase, make sure to choose a product that is enteric coated that is, coated with a protective substance that allows the SOD to pass intact through the stomach acid to be absorbed in the small intestine. All forms of enzymes should be kept in a reasonably cool place to insure potency. Tablets and liquids can be stored in the refrigerator. However, powder and capsule forms should not be refrigerated because they are susceptible to moisture; they should be stored in a cool, dry place. Research has shown that as we grow older, the body's ability to produce enzymes decreases. At the same time, mal absorption of nutrients, tissue breakdown, and chronic health conditions increase. Taking supplemental enzymes can help to ensure that you continue to get the full nutritional value from your foods. We believe that enzyme supplementation is vital for elderly persons.