Foods in the human diet are composed primarily of protein, carbohydrates, and fats. Protein leaves the stomach predominantly in the form of proteoses, peptones, and large polypeptides.² Upon reaching the small intestine, these are further digested by the proteolytic enzymes trypsin, chymotrypsin, and carboxypolypeptidase. Protein digestion primarily occurs in the duodenum and jejunum. Carbohydrates are digested by α-amylase in the pancreatic juice, which breaks starches (converting them into maltose and other small glucose polymers), whereas pancreatic lipase, cholesterol esterase, and phospholipase digest fats.^1,³

Although critical for proper digestion, pancreatic enzymes also aid in a surprising variety of bodily functions, including detoxification, immunity, aging, blood fluidity, and tissue repair. Unfortunately, an inadequate production of, or an excessive requirement for, pancreatic enzymes can occur for a variety of reasons, including genetics, illness, injury, exercise, aging, and toxins (both endogenous and exogenous). Many authorities believe that a deficiency of pancreatic enzymes, for whatever reason, may be the cause of numerous illnesses and degenerative conditions. When a deficiency occurs, enzymes from an external source may be necessary.

History

Pancreatic enzymes have a long history of clinical use. In the early twentieth century, John Beard, a Scotch embryologist, successfully treated cancer using a pancreatic extract, which he described in his book, The Enzyme Treatment of Cancer and Its Scientific Basis. Beard injected pancreatic juice (freshly extracted from young animals) into cancer patients and, when possible, directly into their tumors. He found that the pancreatic juice could inhibit the growth of cancer cells.

In 1934, Dr. Ernst Freund, a Viennese physician, studied the blood of people who were free from cancer and discovered a substance that had the ability to dissolve cancer cells. Patients with cancer did not have this material, which Freund called “normal substance.” In the early 1930s, Professor Doctor Max Wolf worked with Freund in Vienna and successfully identified “normal substance” as an enzyme that decomposes fatty materials and proteins. For his work in the field of enzymes, Wolf is generally considered the father of modern enzyme therapy. The work of Freund and John Beard sparked Wolf’s interest in the possibilities of treating malignant diseases with enzymes. He subsequently founded the Biological Institute of New York City and, after studying various enzymes and enzyme combinations, developed what he regarded as an optimal preparation for the treatment of various acute and chronic conditions. His preparation was a combination of a fractionated hydrolysate of beef pancreas, calf thymus, Pisum sativum (common pea), Lens esculenta (edible lentil), mannitol, and Carica papaya (papaya, a source of the enzyme, papain).

In the 1960s, Irving Innerfield conducted landmark research in the area of pancreatic enzymes, primarily relating to the clinical use of trypsin, chymotrypsin, and pancreatin as well as streptokinase (a microbial proteolytic enzyme). Professor Heinrich Wrba, who for many years was head of the Austrian Cancer Research Institute at the University of Vienna, believed that enzyme therapy should be considered a highly-effective causal anti-cancer compound. Dr. Wrba’s interest in cancer was piqued when he lost a daughter to leukemia. He devoted his life to educating oncologists in Germany and around the world about enzyme therapy.

It was the late Karl Ransberger, however, who continued and refined Wolf’s research, bringing it to doctors, hospitals, and patients throughout the world. Ransberger encouraged and funded research projects in numerous hospitals and universities in Europe, the Americas, and elsewhere. His research, and that of others, validated enzyme therapy’s effectiveness in treating numerous conditions, including arthritis, cancer, multiple sclerosis, cardiovascular disease, human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS).

Pancreatic Enzyme Supplements

The pancreatic enzyme supplements most commonly used in health care are chymotrypsin, trypsin, pancrelipase, and pancreatin. Chymotrypsin and trypsin are proteolytic enzymes that break proteins into peptides. Chymotrypsin liberates the amino acids, L-tyrosine, L-tryptophan, and L-phenylalanine, and other molecules, including several synthetic esters and amides.⁴ Trypsin hydrolyzes primarily lysyl and arginyl residues. Pancreatin contains amylase (which breaks down starch), lipase (which breaks down fats), and protease (which breaks down proteins). Pancrelipase is similar to pancreatin, but with a higher concentration of lipase.

These enzymes are primarily obtained from hog or ox pancreas, but some (such as lipase) can also be obtained from microbial sources (e.g., Aspergillus niger and Aspergillus oryzae). Nevertheless, only enzymes isolated from animal pancreatic glands can be considered pancreatic enzymes.

According to the U.S. Pharmacopeia (USP), chymotrypsin and trypsin are routinely crystallized from ox pancreas gland extract, and pancreatin from both hog and ox sources, whereas pancrelipase is derived from hog pancreas.⁵ Porcine pancreas is especially rich in amylase and lipase, and is similar to the human pancreas.⁴ Bovine pancreas contains considerable amounts of proteolytic enzymes, but substantially lower amounts of lipase and amylase.⁴ Germany, Japan, England, India, and other countries utilize their own pharmacopeia, and foreign companies may use other sources to formulate their enzyme products.

Enzyme concentration and activity levels can vary depending on the age, sex, and species of pork or ox used to produce the supplement. For example, sow glands (from pork) are high in lipase, whereas butcher hogs (young male hogs, up to 90 kg in weight and 6 months of age) are high in protease. Beef cows and bulls have different enzyme levels from those in steers or heifers. Beef, although it provides all three basic enzyme types, does not exhibit the activity levels of pork (which has an activity level one third to one half higher). Furthermore, the physiology of hogs is more similar to that of humans than to that of any other animal.

Enzymes extracted from animal sources are sensitive to environmental changes, so manufacturers take particular care during extraction to control pH (usually with buffers), temperature (using precooled solutions and apparatus), substrate, and proteolysis (controlled through the use of inhibitors) to render a product that is enzymatically active.⁶

Enzyme Standardization

In 2010, the Food and Drug Administration (FDA) began requiring manufacturers of pancreatic enzyme products to test them in clinical trials if those products were prescribed to treat individuals with pancreatic diseases. Until that time, there were frequent inconsistencies in enzyme formulation. For example, a study of six different enzyme preparations found that, in some cases, the actual lipase activity in a product was more than twice that listed on the label.⁷ Another study on nine pancreatic enzyme products found that, although within USP limits, the percentage of lipase activity after dissolution was not always equal.⁸ These inconsistencies in content and activity level could unexpectedly alter patient enzyme requirements.

The FDA’s ruling ensures that pancreatic enzymes are standardized with consistent activity level. Pancreatic enzymes marketed as dietary supplements, however, do not require testing or approval by the FDA. The requirements regarding activity level apply only to those pancreatic enzyme products prescribed for exocrine pancreatic insufficiency due to cystic fibrosis (CF), chronic pancreatitis, and other conditions.

Absorption of Proteins

In the past, it was believed that the intestinal epithelial mucosa was impermeable to large protein molecules.⁹ However, research over the past several decades has shown that the intestinal epithelium can be crossed by macromolecules, including intact proteins such as proteolytic enzymes.¹⁰

These macromolecules normally penetrate the mucosal surface via the transcellular route as, in healthy mucosa, the tight junctions (zonula occludens) between the enterocytes prohibit paracellular passage.¹¹ Binding to the luminal membrane of the enterocyte is followed by phagocytosis.¹² Some of the vacuole membrane vesicles formed fuse with lysosomes, and within the resulting phagolysome, the peptides and proteins may be hydrolyzed by lysosomal enzymes.¹³ Other macromolecules avoid intracellular digestion and are passed from the enterocytes through the basolateral membrane into the interstitial space.¹⁴ In the interstitial space, the macromolecules become available to macrophages and lymphoid cells.¹⁵ Those molecules not taken up by macrophages or lymphatic cells eventually pass from the interstitial space into the blood or lymph.¹⁶

The transport of macromolecular material from the lumen to the interstitium has been extensively studied in the epithelium covering the lymphatic structures, such as Peyer’s patches or isolated follicles.¹² In these regions, specialized enterocytes, the follicle-associated epithelium cells¹⁷ or M-cells¹⁸ (so called because of their occurrence in the microfolds of the luminal surface), transport macromolecular material in both directions.¹⁷ The gut-associated immune system is thus supplied with antigenic macromolecules from the intestinal lumen.¹⁹ The immunoglobulins produced by the plasma cells in the lamina propria (mainly immunoglobulin-A) are transported transcellularly to the luminal surface.

The exact level of the intestinal absorption of intact molecules or large breakdown products of dietary proteins is not yet totally clear and can vary by individual.²⁰ Although it is generally assumed that, apart from a very small proportion, all protein is hydrolyzed into amino acids or low-molecular-weight peptides before absorption by the mucosa, some research supports the hypothesis that a considerable proportion of dietary protein is taken up in the form of macromolecules and is only then hydrolyzed intercellularly in the peripheral tissue into amino acids (a process called “distributed digestion”).²¹

Understanding the Absorption of Enzymes

Understanding the intestinal transport of macromolecules is especially important for understanding the functions and absorption of enzymes specifically. Hydrolases such as trypsin or elastase can be transported functionally intact into the bloodstream from the lumen of the gut. These circulating proteinases are bound to antiproteinases, such as alpha₂ macroglobulin or alpha₁ antiproteinase,²² and can be resorbed from the main bloodstream by pancreatic cells (enteropancreatic circulation as an enzyme conservation process).²³ Thus, the intestinal absorption of intact enzymes appears to be important for the balance between hydrolases and antiproteinases in the intracellular space,²⁴ and is an important factor for the establishment and maintenance of the internal stability in the body.

Although there are a number of absorption mechanisms, the primary mechanism for the enteral absorption of enzymes and other macromolecules is pinocytotic transfer by the M-cells of the small intestinal epithelium. The enzymes connect to a receptor in the intestinal wall mucosa and are then absorbed into the wall by pinocytosis, guided through the intestinal cells in vesicles, and finally released into the blood by exocytosis.²⁵

To clarify rate of absorption, Steffen et al ²⁶ investigated the absorption of an enzyme mixture “A” (EMA), which contained 100 mg of pancreatin, 60 mg of papain, 10 mg of lipase, 10 mg of amylase, 24 mg of trypsin, 1 mg of chymotrypsin, 45 mg of bromelain, and 50 mg of the bioflavonoid rutin in rabbits. Using electrophoresis, these researchers found that entire enzyme molecules were absorbed. Although enzyme particles were also present, the ratio to the entire amount administered was not measured. EMA was found in both lungs and liver after 1 to 2 hours. After 1 to 4 hours, approximately twice as much EMA was found in the liver as in the lungs. The absorption maximum in all animals occurred approximately 1 hour after administration. After 24 hours, EMA was no longer found in either the lungs or liver.

The absorption rate of individual and combined enzymes can be found in Table 111-1.^27,²⁸ The absorption rate of orally-ingested EMA is about 20% within 6 hours.¹⁹

TABLE 111-1 Absorption Rate of Individual and Combined Enzymes (within 6 Hours)^27,²⁸

ENZYME	ABSORPTION RATE (%)
Amylase	45
Chymotrypsin	14-16
Pancreatin	18-19
Papain	6
Trypsin	26-28
Enzyme combination (bromelain, chymotrypsin, pancreatin, papain, and trypsin, with the bioflavonoid rutin)	22

Factors Affecting Enzyme Activity

Numerous factors including pH, temperature, substrate (and substrate concentration), cofactors, metal ions, inhibitors, and coating can affect the activity of supplemental enzymes.

Optimal pH Range

Each enzyme has an optimal pH range, depending on such variables as temperature and substrate concentration at which the enzymatic catalytic reaction occurs most rapidly. Chymotrypsin has an optimum pH of 8.0, has reversible denaturation at a pH below 3.0, and becomes inactive at a pH above 9.0.⁴ Trypsin has an optimum pH between 7.0 and 9.0, is stable at a pH of 3.0 (and at low temperature), and is irreversibly denatured at a pH of 9.0 or higher.⁴ The pH of the normal human stomach is 1.5 to 3.0,²⁹ low enough to denature or inactivate some or all of a pancreatic enzyme supplement if it is not enterically coated or otherwise treated to protect it from a low-pH environment.

The Effects of Temperature

In general, an increase of 50° F (10° C) in the enzymatic environment approximately doubles the rate of the chemical reaction.³⁰ However, because enzymes are proteins, excessively high temperatures can denature them, thus destroying their activity. Optimum temperature for an enzyme is the temperature at which the catalyzed enzymatic reaction progresses most rapidly without damage to the enzyme. This temperature can vary by enzyme. This is a good rationale for avoiding hot beverages when taking enzyme supplements.

The enzymes in the human body develop high levels of activity at about body temperature, increasing to maximum at about the temperature of a severe fever, that is, 104° F (40° C).

Substrate Concentration

The rate of any reaction is accelerated by raising the substrate concentration until the enzyme is saturated by substrate. At this level, the rate of reaction becomes independent of substrate concentration and is no longer accelerated by the addition of more substrate. This is why it is particularly important to ingest sufficient quantities of supplemental enzymes (which vary according to the condition being treated).

Cofactors

Although all enzymes consist of protein, some are complex proteins, that is, they have a protein component and a “cofactor.” If the cofactor is removed, the protein (no longer active enzymatically) is called the apoenzyme. A cofactor might be a metal (e.g., iron, magnesium, copper, or zinc), a prosthetic group (a moderately-sized organic molecule), or a coenzyme (small organic compound). Prosthetic groups and metals can aid in the catalytic function of the enzyme, whereas coenzymes take part in the enzymatic reaction. Many vitamins, trace elements, and minerals essential to human bodily function are part of enzymatic cofactors. So the physician must ensure that his or her patients take multivitamins and multiminerals to “feed” their enzymes.

Coenzymes are essential for the activity of many enzymes and serve as a type of substrate in certain reactions. In these reactions, the coenzyme is converted to a form no longer active in catalyzing the reaction. The reaction requires a mix that contains one molecule of cofactor for every molecule of substrate to be converted.

Metal Ions

Specific metal ions are required for the activity of many enzymes. Some metal ions increase enzyme activity and others decrease or inhibit it. Calcium, cobalt, copper, iron, magnesium, manganese, molybdenum, potassium, and zinc are the most common enzyme activators in humans. Certain heavy metal ions inhibit enzyme reactions; they are barium, lead, and mercury, and they combine with the sulfhydryl reactive group (−SH) that is part of the active site of many enzymes.

Inhibitors

Ions, atoms, or molecules that terminate or retard enzyme activity are called inhibitors. They are classified as either noncompetitive or competitive. A noncompetitive inhibitor combines with the enzyme at a location other than the active site. The noncompetitive inhibitor retards the conversion of the substrate by the enzyme, although it does not affect the bonding of the substrate of the enzyme. An inhibitor is classified as competitive if it combines with the active site of the enzyme, preventing the substrate from having access to the active site.

Supplement Coating

The pH of the stomach’s hydrochloric acid secretions is about 0.8.³¹ This low pH inhibits bacterial growth and activates certain enzymes. This acidic nature, however, can destroy pH-sensitive supplemental enzymes. For this reason, many enzyme products are enterically coated. This coating allows the product to reach the small intestine before disintegrating. Other products are encapsulated in “microspheres,” delaying disintegration. For example, pancreatic protease encapsulated with a mixture of cellulose acetate phthalate and maize starch can remain stable in simulated gastric conditions (pH of 3.97) for at least 3 hours.³² This would theoretically provide enough time for the capsule to pass through each part of the gastrointestinal tract. The capsule then disintegrates rapidly under pH 6.82 and temperature of 39.5° C (as would occur in the small intestine).³²

Nanotechnology is opening a new field for the delivery of enzymes and other small proteins. Nanotechnology is the study of matter as small as one billionth of a meter. According to the National Nanotechnology Initiative, nanoparticles are being used in timed-release drug delivery.³³ Enzymes can be attached to nanoparticles and actually maneuvered to destroy diseased cells. Research on nondegradable nanocapsules showed that proteins can be efficiently transported to individual cells, surviving different pH levels.³⁴ So, it is no wonder that enzymes (which are proteins) can also be attached to nanoparticles and used to treat disease at the cellular level.

Measuring Enzyme Activity

When considering enzymes and enzyme applications, the physician must understand the variables affecting their performance. Selection of an enzyme for therapeutic purposes requires more than knowing whether a given product contains amylase, protease, lipase, or other enzymes. The activity levels of the enzymes are critical.

As mentioned previously, the manufacturers of pancreatic enzymes prescribed to treat specific conditions must clearly disclose content and enzyme activity levels. Unfortunately, the same is not true of enzyme products sold as dietary supplements, whose labels may not indicate enzyme activity levels. In addition, even when the activity is stated, the consumer has no way of knowing which enzyme assay the manufacturer used unless the label also indicates that the product conforms to the guidelines of the USP. This is particularly confusing because activity levels are greatly affected by the conditions under which the assay was performed (including temperature, pH, and substrate).

Adding to the confusion, enzyme manufacturers utilize diverse assay methodologies, making direct comparison of competing products difficult, if not impossible. Utilizing a single assay system (such as detailed in the USP) is necessary to directly compare competitive products. Several standardized assay systems are available for enzyme suppliers and are found in the USP (for a definitive assay), the NFIA Laboratory Methods Compendium, and the Food Chemical Codex.

Incomplete labeling and the inconsistent use of standardized assay methodologies make evaluating competitive products extremely challenging. Price could be the first indication of inequities in assay procedures. For example, if company A is selling a product at 1000 U/g for $30 a bottle, and company B is selling a product at 5000 U/g for $10 a bottle, the units are most likely not the same.

For clinical reliability, one must use only appropriately labeled products or obtain the assay procedures from each of the manufacturers. If possible, competitor products should be compared by means of assays performed in an independent laboratory.

Clinical Applications

Historically, enzyme therapy has been used in a wide variety of applications, ranging from oral supplementation to treat pancreatic insufficiency, to the centuries-old external application of enzymes to treat leg ulcers, topical wounds, wrinkles, blemishes, episiotomies, scars, and so on. Usually administered in capsules or tablets, enzymes are also available as lozenges (dissolved in the mouth) or in powder. Topical enzyme ointment is currently used to debride necrotic tissue and other wound debris. Enzymes can also be administered by injection (normally in a hospital setting because of the risk of anaphylactic reaction) or rectally, by retention implant.

Enzymes can be used individually, but are typically more efficacious when used in enzyme mixtures. Enzyme combinations are not simply intensified forms of pancreatin. An enzyme combination has a number of therapeutic advantages over a preparation with only one or two components. Combining enzymes from different sources–animal, plant, and fungi–results in a wider range of optimal pH, synergism of the combined enzymes, greater absorption, higher level of effectiveness, and broader range of application. For example, one German product contains an enzyme extract consisting of proteinases, triacylglycerol lipase, and alpha-glycosidase (amylase); minor amounts of elastase, nuclease, and carboxypeptidase; and calcium ions to boost activity.

Dr. Peter Streichhan, a well-known enzyme researcher, stated that certain enzymatic mixtures have a broader range of action than pancreatin, bromelain, or any other standardized monohydrolytic preparation—this is because certain enzyme mixtures characteristically possess differences in optimal pH and also differences in reactive properties of the proteolytic, lipolytic, and/or amylolytic-acting hydrolases.³⁵

It should be remembered that, at the beginning of therapy, an individual’s symptoms may occasionally become more severe. This is a sign that a therapeutic reaction is occurring and should be evaluated positively. The medication need not be discontinued, although a temporary reduction in dose might be advisable.

Clinical uses of individual enzymes can be found in Boxes 111-1 through 111-5, whereas clinical uses of combinations can be found in Box 111-6. For more information on how enzymes can treat more than 150 conditions, please see the author’s book, The Complete Book of Enzyme Therapy.

BOX 111-1 Clinical Applications of Chymotrypsin