Vital FUNCTIONS of Digestive Enzymes


Enzymes, mostly proteins, have some involvement in every metabolic activity in the body--from digesting and assimilating food to catalyzing the thousands of reactions that are necessary for the body to function. Enzymes are involved in the synthesis and repair of DNA; in the production of proteins, fats, and connective tissue necessary to grow and regenerate cells; and in the breakdown and detoxification of cellular wastes that are the by-product of normal metabolism.

Humans and animals are capable of making most of their own metabolic enzymes as long as the nine essential amino acids are available in adequate amounts in the diet. The other amino acids necessary to produce all proteins and most enzymes can also be synthesized by the body, although the amount and types vary from species to species (reflecting the specificity of their dietary niche) and even from individual to individual (reflecting the actual content and variety of their diet).

Unfortunately, the cellular machinery that drives all this production of amino acids, proteins, and, therefore, most enzymes tends to wane with age, cellular damage, and dietary deficiencies, leading to depletion of the total body supply and frequently contributing to poor health.

Although the body produces and needs hundreds of enzymes, most of the energy expended by the body goes toward the production of digestive enzymes, since food is the ultimate fuel source for all metabolic activities.

Most people know a bit about digestive enzymes, even if from their middle school biology class. What they learn mostly is about the body's digestive enzymes and where, if not how, they work. To review, we will follow a food particle through its usual route.

When food is put in the mouth, amylase is released in the saliva to start the breakdown of starches as the food is chewed. Unfortunately, most people today eat too quickly for that source of amylase to do us much good. Next, as the food enters the stomach, pepsin, a protease, kicks in to partially break up proteins into peptides (groups of amino acids). Other proteases, such as trypsin and chymotrypsin, are also secreted by the pancreas where the proteins are further broken down. Each of these proteases works on a different part of the protein molecule. They are additive in function, not redundant. Pepsin requires the very acid pH of the stomach to work. The common use of antacids and acid suppressing medications, as well as the natural reduction in stomach acid associated with aging, may render these naturally occurring enzymes less or even ineffective. This leaves the remaining job of protein digestion disproportionately to the pancreas and small intestine, which frankly had counted on their buddy the stomach to keep up its end of the job.

The pancreas also produces amylase to further break down starch and lipase to break down fats. Lipase works in conjunction with bile produced by the liver to emulsify and break down fat molecules into particles small enough for the small intestine to absorb and use to feed your body. The small intestine also absorbs the broken down starches sugars and proteins after the work of enzymes is complete. By the time the food has reached your large intestine, the process of nutrient absorption is largely but not completely finished. There occurs the removal of excess fluid from the waste, the processing of undigested foods, and the bacterial breakdown of waste.

What is missing from this cooperative story above is how inherently inefficient the system is. If we rely only on it to keep the machinery moving, the machine will be stressed, the product will be inadequate, and the possible effects on the body are intestinal discomfort, bowel changes, poor nutrition, and premature aging of the body's repair mechanisms.

Why this inefficiency in what seems like a well designed system? Because the system was never designed, so to speak, to be all enzymes to all foods. Humans and animals possess largely specialized digestive tracts to reflect their respective diets. Herbivores, such as cattle and deer, produce cellulase to help break down the plant cells that make up their diet. The raw grasses, plants, fruits, and grains that they eat are loaded with just the digestive enzymes that are needed to process that food itself. If cattle were fed only cooked grain, they would die (which is why the feedlots are the last stop for them), although digestive enzymes are added as a supplement to their food, partially to control their contribution to greenhouse gases.

Carnivores eat not only meat but also the vegetable filled guts of their prey, thus deriving live digestive enzymes from their meals, even if they don't graze themselves. Because they eat their prey raw, these enzymes remain active and are a vital part of their nutrition. Anyone with a cat can attest to their affinity for eating grass and plants. They crave it because they need it.

Omnivores, like humans, eat a diet of variety and opportunity. If it can be hunted, caught, grown, picked, dug up, cultured, or fermented, we humans eat it, as do most other omnivores that thrive in our environment--on a variety of foods, including our leftovers. We are the only animals to eat such a high proportion of our food cooked. Cooking foods, especially meats, initially was a huge boon to survival of our species, as it allowed for better assimilation of some nutrients, especially proteins and calories, and helped break down the indigestible cell wall of plants to allow access to their nutrients.

As long as the human diet included plenty of raw and whole food as well, the balance of ingested plant based digestive enzymes to metabolic enzymes allowed the body to assimilate these nutrients well. Today, however, many of us eat an excess of cooked, processed foods that are devoid of" active enzymes, and a paucity of foods high in natural enzyme activity.

The "life force" of raw food enzymes is what allows a fresh bean to sprout or a green tomato to ripen. Cook, freeze or pickle a bean or tomato and they will never ripen, even though the contents of that bean or tomato remain otherwise intact. That life force depends on the enzymes retaining their unique three-dimensional shape, such as a key requires a very specific shape to fit into a specific lock. In order to preserve that unique shape, enzymes must be extracted whole and intact, in their functional state. Ironically, the heavy nutrient load of cooked food when offered to the body devoid of the enzymes that food in its raw state would provide, can lead exactly to the nutrient absorption problems that cooking initially addressed.

The body compensates by producing more endogenous enzymes. In the face of decreased absorption of the nutrients, it needs to produce them, thus depleting the entire body store of enzymes and enzyme precursors.

Even in a modern diet relatively rich in raw foods, unless these foods are very fresh and untreated, beneficial enzymes may be largely inactivated or in many instances contain a very narrow spectrum of active enzymes. Short of eating organic produce from your own garden (and chomping on some wild berries and grasses while you are at it), taking supplemental plant-based digestive enzymes is the only reliable way to insure adequate intake of enzymes to protect the balance between your digestive and metabolic needs and the raw materials needed to provide them.

Unlike vitamins and minerals, enzymes cannot be produced chemically. Because the function of enzymes is dependent on their natural three dimensional conformation (and this is easily destroyed by heat or chemicals), they must be extracted whole, either from living plants or, in most pharmaceutical products, from the organs of slaughtered animals.

Unlike supplemental enzymes of animal origin, plant-based enzymes, including those discussed above and especially those found in broad-spectrum supplements, work over a broad pH range. This allows them to aid in predigestion and digestion in the stomach, and to continue aiding in digestion throughout the digestive tract, thus easing the stress on the body's own enzyme pool and, more importantly, allowing the full extraction of nutrients from the foods we eat.

Digestive plant enzymes are unique in that they not only overlap in function with the body's own metabolic enzymes but provide many enzymes the body cannot make in sufficient quantities or at all.

Lactase, the enzyme most familiar to us, is absent in all but a small number of adults. Indeed, the lactase that infants and children produce to digest mother's milk is produced by entirely different cells than that produced by adults, and, in most people, it wanes by adolescence. Lactose intolerance, especially to cow's milk, is very common, especially in non-caucasians. Cellulase, xylase and xylanase help break down otherwise indigestible components of plant fiber, allowing maximum extraction of nutrients. Alpha-galactosidase aids in the digestion of the complex sugars found in beans and cruciferous vegetables such as broccoli and cauliflower. These foods, which can otherwise cause excessive bloating and flatulence, are better digested in the presence of this supplemental enzyme, which humans cannot produce.

Although some of my patients, because of pancreatic problems, require animal based digestive enzymes, this is relatively rare. What are not rare however are digestive diseases of every other stripe, and for these I frequently recommend a good quality plant-based digestive enzyme.

With so many choices available to the consumer today, selecting a product that is right for you can be confusing. Although many good products are available, I look for and recommend blends that provide a full spectrum of digestive enzymes along with certain botanicals that may have synergistic beneficial effects on digestion and metabolism.

The product should contain specific enzymes to assist in the breakdown of proteins, fats, carbohydrates, grains, fiber, nuts, seeds, soy, legumes, fruits, vegetables, and all components of dairy products. Given the rapid globalization of our society, and with it our increasing exposure to foods novel to our systems (imagine the first time a Native Alaskan ate tofu), a digestive enzyme supplement lacking in any of these compliments is inadequate.

In addition, I recommend a product that includes traditional botanicals such as ginger root, turmeric, naringin, aloe vera, and cat's claw for their soothing effect on the digestive tract. The product I recommend also contains barley, oat and wheat grasses as powerful sources of nutrition and beneficial fiber.

The proper way to take a digestive enzyme supplement is to swallow one at the beginning of a full meal and an additional one during or at the finish of the meal to ensure that food and enzymes travel together. For a snack or smaller meal, one capsule may suffice. Occasional indigestion between meals may be relieved by one capsule taken with a glass of water.

Immediate benefits of this therapy should include reduction in dyspepsia and intestinal distress. Long-term benefits, which may be more subtle, include improved nutritional status and an overall reduction in stress on the body's metabolic systems. Digestive enzymes have also been shown to have anti-inflammatory properties, not only on the bowel but also in the blood stream, although the mechanism is not well understood.

As with any medication or supplement, there are people who should not take these products. Anyone who is pregnant, nursing or on prescription medications for diabetes or hypertension should consult first with a physician knowledgeable about their condition and supplemental plant enzymes. The latter may be harder to find, but not impossible, as many of my colleagues as well as myself are embracing nutritional supplements as a complement to our traditional allopathic practice.

For more information on digestive enzymes call 1.800.574.1961 or visit



By Joyce Luteyn, Dr.

Joyce Luteyn, M.D., is a board-certified family practitioner. She received her medical degree from the University of Washington, and completed a UW affiliated family medicine residency in Vancouver, Washington, in 1997. She has been in fulltime practice for eight years in Olympia, where she lives with her husband and two children. Her practice encompasses the full range of primary care for patients of all ages.

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