Linda L. Isaacs, M.D.
Digestive enzymes are critical to survival. They turn the food we eat into smaller pieces that we can then burn for energy or use as building blocks to form and repair the components of our bodies. But they also play key roles in the defense against cancer and the repair of injury, helping to orchestrate the intricate dance between growth and breakdown of tissue that is important in both these processes.
But before we get into the details, let’s define a few terms. What are enzymes? Enzymes are molecules, usually proteins, that are created by living organisms to make chemical reactions happen. For example, our bodies break down sugar to create energy. If you mix sugar into a glass of water, it will just sit there; it might take decades for the chemical reactions to occur that would liberate energy. But in the presence of the enzymes in our body that work on sugar, it rapidly gets turned into carbon dioxide and water, releasing energy along the way. Various types of enzymes perform all of the functions in our bodies.
Enzymes for Digestion
Specifically, digestive enzymes break down the food that we eat. There are three general categories:
- Proteases break down protein (also called proteolytic enzymes)
- Lipases break down fat (fats are also called lipids)
- Amylases break down complex carbohydrates (amylum is Latin for starch)
Digestive enzymes are made by the salivary glands, the stomach lining and the intestinal tract. However, most of the digestive enzymes come from the pancreas. In response to a meal, the pancreas sends large amounts of all three types of digestive enzymes into the intestinal tract to help break down food.
The pancreas can be damaged by various diseases or chemical exposures, causing a shortage of pancreatic enzymes (known as pancreatic insufficiency). If a patient has a severe case of pancreatic insufficiency, they cannot digest their food properly, and the undigested food shows up as oily bowel movements. They lose a great deal of weight, and they also suffer from intestinal upset because the bacteria living in their guts feed on the undigested food and produce gas.
The function of the digestive enzymes was discovered more than a century ago, and methods of concentrating them into medications or food supplements also go back for decades. While these products can be helpful for patients with pancreatic insufficiency, they have also been found to be helpful for less serious intestinal issues such as gas, bloating, or intestinal discomfort. A 2018 article in the Journal of Digestive Diseases reviewed 60 years’ worth of studies on this topic.1
Do Pancreatic Enzymes Do More than Digest Food?
For many years, the medical world believed that pancreatic enzymes only digest food and that administering them to patients could only help them with their digestion. Whenever anyone would suggest that pancreatic enzymes were helping with other conditions, the idea would be ridiculed, because “everyone knew” that the enzyme molecules were too big to be absorbed from the intestinal tract into the body.
In the twenty-first century, new discoveries mean this viewpoint is changing. It turns out that proteases, enzymes that cut proteins into smaller pieces, have a much wider role in the body than previously believed. Many types of cells have proteins on their outer surface called protease-activated receptors. They look like a wad of protein in the cell membrane, with an end protruding on the outside of the cell. When a protease snips off part of that exposed tail, the shape of the whole receptor molecule changes, signaling the inside of the cell to take some action.
There are different proteases that snip that exposed segment in different places, causing different cellular behavior changes, and there are four different types of protease-activated receptors on cells. All these discoveries have taken proteases from being virtually ignored, to becoming the center of a lot of research trying to better understand their functions.2
But are enzymes too big to be absorbed? That theory is starting to crumble as well. A recent article about protease-activated receptors in the cells of the gut lining suggests that these receptors control what size molecules can be absorbed.3 The proteases may act on the receptor that then lets them pass into the body from the intestinal tract.
Pancreatic Enzymes and Cancer
More than a century ago, the British scientist John Beard claimed that pancreatic enzymes played a role in cancer prevention and treatment. Beard was a professor of embryology, the study of the very early stages of development. He was especially interested in the early stages of the placenta, the tissue that forms the anchor between the mother and the baby that allows for nutrients to be delivered to the baby and wastes to be taken away.
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In the placenta’s earliest stage, cells called trophoblasts attach to the inside of the mother’s womb, invade and create a blood supply – looking and behaving like cancer. But at a certain point, around two months into a human pregnancy, the trophoblast cells stop invading and mature into the placenta, which will then neatly detach after the baby’s birth. Beard believed that if he could find out what signaled the trophoblast cells to change character, he might find a treatment for cancer. He looked at many different events in the mother and the baby to see what the signal might be, and he found that the nature of the trophoblast changed around the time the baby started making pancreatic proteolytic enzymes – months before they would be needed for digestion.
He published his findings in various medical journals and finally put all his work together in a book called The Enzyme Treatment of Cancer and Its Scientific Basis, published in 1911.4 After learning of his theory, various physicians tried using pancreatic proteolytic enzymes for cancer patients with mixed results. Beard felt that treatment failures were due to the poor quality of many of the enzyme preparations on the market. His theories were eventually put aside by the medical world, not because they had been tested properly and found to be wrong, but because surgery and radiation became the dominant treatment methods.
Since Beard’s era, a few physicians have tried pancreatic proteolytic enzymes against cancer; a full summary is available in a lengthy article I wrote for the medical journal Integrative Cancer Therapies that is freely available online.5 My own work in this area stems from the experiences of William Donald Kelley, DDS, an orthodontist who created a nutritional program for himself when he was told he had cancer in the early 1960s. He was having terrible digestive problems and took large amounts of pancreatic enzymes to address this. He then noticed a change in the character of the mass in his abdomen, and realized that the pancreatic enzymes he was taking were having an effect on his cancer. He devised a program for himself of dietary modification, detoxification, and supplementation including large amounts of pancreatic enzymes. After he recovered, people began to seek him out looking for advice about how to deal with their own cancers or other health problems.
In the early 1980s, Nicholas Gonzalez, MD, learned of Kelley’s work and began reviewing his records to assess whether there was anything of value there. I met Nick when he was partway through this effort; subsequently, he and I both spent our professional careers utilizing and researching this work, with many case reports available from Kelley’s files and our own that document long-term survival and/or resolution of disease in patients with appropriately diagnosed cancer.6,7 Examples include a woman diagnosed with pancreatic cancer in her early 60s, who is still alive 20 years later and was able to see her grandchildren grow up; a man with metastatic colon cancer whose survival has amazed his oncologist, and who has been able to be there for his young son; and many others. Please visit my website (drlindai.com) for more details.
An obstacle during our research efforts was other physicians’ belief that pancreatic proteolytic enzymes have no role besides the digestion of food, and so have no role in cancer. But the recent medical literature describes how protease-activated receptors are present on the surfaces of cancer cells. Some scientists have even documented a positive effect of pancreatic enzymes on the behavior of cancer cells in experimental models.8 Protease-activated receptors are also present on the surface of trophoblast cells, lending some support to Beard’s theory that pancreatic enzymes from the fetus could modify their behavior.9
Enzymes and Wound Healing
With the recognition of the digestive powers of the enzymes the pancreas makes, there has been a long tradition of use of pancreatic enzymes for wound treatment, both applied directly to the tissue and taken orally. As it turns out, many of the molecular mechanisms involved in wound healing are also present in cancer, so if proteases can play a role controlling the behavior of cancer, it makes sense that they could also control the behavior of wound healing and affect the metabolism of fibrous tissue throughout the body.
A 1970 article in Postgraduate Medical Journal reviewed the use of enzymes applied to the skin and taken by mouth to address wound healing and trauma.10 Apparently, many practitioners felt they were useful, but formal research on the subject was challenging. Studies run by strong advocates of the treatment were discounted as biased, because it was hard to measure improved healing. Also, no one believed that pancreatic enzymes taken orally could have a systemic effect. Therefore, the use of pancreatic enzymes for wound healing gradually became uncommon in the United States.
However, they continued to be used and studied in other countries. A 2018 article in the journal Advances in Therapy discussed results with a product containing a combination of two pancreatic proteolytic enzymes, trypsin and chymotrypsin.11 The product, taken by mouth, was found to be helpful in speeding the resolution of bruises, and increased the recovery rate in ankle sprains. The product also helped resolve post-operative swelling and inflammation in orthopedic cases, and helped with sciatica pain due to disc disease.
It is not clear how proteases act to promote tissue healing, but it is interesting to note that the same protease-activated receptors that are present in cancer cells are also present in fibroblasts, the cells that lay down the connective tissue that is a key part of wound healing.
Pancreatic digestive enzymes can certainly help digest food, and given the widespread issues many people have with digestion, that alone is a good reason to supplement them. But there is also some evidence that they can be helpful for tissue maintenance and repair, and for the prevention and treatment of cancer. All in all, adding some digestive enzymes to your supplement protocols may be beneficial for your health.
- Graham DY, Ketwaroo GA, Money ME, Opekun AR. Enzyme therapy for functional bowel disease-like post-prandial distress. J Dig Dis. 2018;19(11):650-656. doi: 10.1111/1751-2980.12655.
- Verhamme IM, Leonard SE, Perkins RC. Proteases: pivot points in functional proteomics. Meth Mol Biol (Clifton, NJ). 2019;1871:313-392. doi: 10.1007/978-1-4939-8814-3_20.
- Pontarollo G, Mann A, Brandão I, Malinarich F, Schöpf M, Reinhardt C. Protease-activated receptor signaling in intestinal permeability regulation. FEBS J. 2020;287(4):645-658. doi: 10.1111/febs.15055.
- Beard J. The Enzyme Treatment of Cancer and Its Scientific Basis. London: Chatto and Windus; 1911.
- Isaacs LL. Pancreatic proteolytic enzymes and cancer: New support for an old theory. Integr Cancer Ther. 2022;21:15347354221096077. doi: 10.1177/15347354221096077.
- Gonzalez NJ, Isaacs LL. The Gonzalez therapy and cancer: a collection of case reports. Altern Ther Health Med. 2007;13(1):46-55.
- Isaacs LL. An enzyme-based nutritional protocol in metastatic cancer: case reports of a patient with colon cancer and a patient with lung cancer. Altern Ther Health Med. 2019;25(4):16-19.
- Peran M, Lopez-Ruiz E, Garcia MA, et al. A formulation of pancreatic pro-enzymes provides potent anti-tumour efficacy: a pilot study focused on pancreatic and ovarian cancer. Sci Rep. 2017;7(1):13998. doi: 10.1038/s41598-017-14571-x.
- Even-Ram SC, Grisaru-Granovsky S, Pruss D, et al. The pattern of expression of protease-activated receptors (PARs) during early trophoblast development. J Pathol. 2003;200(1):47-52. doi: 10.1002/path.1338
- Miller RR, De Young DV, Paxinos J. Enzymes for trauma. Postgrad Med J. 1970;46(533):154-156. doi: 10.1136/pgmj.46.533.154.
- Shah D, Mital K. The role of trypsin:chymotrypsin in tissue repair. Adv Ther. 2018;35(1):31-42. doi: 10.1007/s12325-017-0648-y.
Linda L. Isaacs, M.D., received her medical degree from Vanderbilt University. She is certified by the American Board of Internal Medicine. She is located in Austin, Texas, but has patients from all over the United States and abroad. In her practice, she uses nutritional protocols to treat patients diagnosed with cancer and other serious degenerative illnesses. She has published articles about cancer in the peer-reviewed journals Nutrition and Cancer, Alternative Therapies in Health and Medicine, and Integrative Cancer Therapies. Visit her website at drlindai.com.