Enzyme Therapy
Other common name(s): digestive enzyme therapy, pancreatic enzyme therapy, systemic enzyme
therapy, proteolytic enzyme therapy
Scientific/medical name(s): none

Description
Enzyme therapy involves taking enzyme supplements as an alternative form of cancer treatment.
Enzymes are natural proteins that stimulate and accelerate many biological reactions in the body.
Digestive enzymes, many of which are made in the pancreas, break down food and help with the
absorption of nutrients into the blood. Metabolic enzymes build new cells and repair damaged
ones in the blood, tissues, and organs.

Overview
There is no reliable scientific evidence that enzyme supplements are effective in treating cancer.
It is not known whether they may help make other forms of treatment work better or improve
quality of life in cancer patients. Research to determine the safety and effectiveness of different
enzyme preparations is currently under way.

How is it promoted for use?
Enzymes are sometimes used in conventional medicine. For example, the approved
chemotherapy drug asparaginase is an enzyme. Some enzymes are also used for other serious
illnesses. Pancreatic enzymes may be given to treat digestive problems resulting from removal of
the pancreas or certain diseases of the pancreas.
However, some alternative medicine practitioners claim that digestive enzyme supplements not
only relieve digestive problems, such as ulcers and food allergies, but also strengthen the
immune system, improve circulation, ease the pain of sore throats, aid weight loss, and relieve
hay fever, ulcers, and rheumatoid arthritis. Proponents also claim that certain enzymes remove
the protective coating from cancer cells, allowing white blood cells to identify and attack the
intruders.
Because they are promoted as dietary supplements (and not as drugs), manufacturers can market
them in the United States without proving they are effective, or even safe, as long as they don’t
claim they can prevent, treat, or cure a specific disease.

What does it involve?
Human cells naturally produce about 10,000 different enzymes which are essential in normal
metabolism. Enzyme supplements are extracted from animal organs and some plants. Among the
most popular enzyme supplements are pancreatic enzymes, which come from an animal
pancreas.
Enzyme supplements are available in pills, capsules, and powders. Supplements often consist of
combinations of several different enzymes. Large amounts of supplements are often taken each
day. There is currently no established safe or effective dosage.
Enzyme therapy is a part of some forms of metabolic therapy, including Gerson therapy and the
Kelley and Gonzalez programs. (For more detailed information on these regimens, see our
documents on Gerson Therapy and Metabolic Therapy.)

What is the history behind it?
Pancreatic enzymes were reportedly first used to treat cancer in 1902 by John Beard, a Scottish
scientist. German researchers later used enzyme therapy to treat patients with multiple sclerosis,
cancer, and viral infections. Some enzyme mixtures are still commonly used in several European
countries.
Dr. Edward Howell introduced enzyme therapy to the United States in the 1920s. He believed
that by eating raw meat, people created an enzyme surplus, which resulted in better health and
increased resistance to disease.
Other practitioners have advocated the use of enzyme therapy since then, often as part of a larger
metabolic therapy regimen. One of these, the Gonzalez regimen, is currently under study.
At least one enzyme preparation is currently being studied in the US for use along with
chemotherapy in patients with cancer.

What is the evidence?
There have been no well-designed studies showing that enzyme supplements are effective in
treating cancer. Experts question whether enzymes taken as oral supplements can reach tumors
through the bloodstream because they are broken down into amino acids before being absorbed
in the digestive tract.
Studies of enzyme supplements to ease the side effects of cancer treatment have reported mixed
results. Two studies done in India reported that the side effects of radiation therapy in cancer
patients getting pancreatic enzyme supplements were lower than in those not getting them.
However, these studies were not blinded – that is, patients knew whether or not they were getting
the enzymes. A blinded German study, in which patients didn’t know whether they were taking
the enzymes or placebo pills, did not find any benefit.
Several studies, done mainly in Eastern Europe, have looked at the possible effects of adding
enzyme supplements to conventional cancer treatment. They have generally found that
supplements may improve quality of life, and could possibly have other benefits as well.
However, these studies are not considered scientifically strong. They looked back in time at
patients who were already treated and were not randomized (where patients are randomly
assigned to one treatment or the other) or blinded. Nonetheless, a randomized study of the
addition of enzyme therapy to standard chemotherapy for multiple myeloma patients is under
way in the United States.
A small pilot study was published several years ago, consisting of 10 outcomes of patients with
advanced pancreatic cancer treated with the Gonzalez regimen (which includes large doses of
pancreatic enzymes). The patients were reported to have longer survival times than would be
expected with standard treatment. A clinical trial sponsored by the National Cancer Institute is
now under way to compare the Gonzalez regimen to standard treatment for advanced pancreatic
cancer. While the study was originally supposed to be randomized, it is no longer because patient
accrual to the study has been slow. Many patients did not like the idea of being randomized to
one form of treatment or the other.
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Are there any possible problems or complications?
There is very little information available on the safety of enzyme supplements. Some
manufacturers recommend speaking with your doctor if you are taking any blood thinning
medicines.
Care should be taken to make sure that any diet containing raw meat or raw meat juice is free
from bacterial contamination, especially for people with weak immune systems.
Women who are pregnant or breast-feeding should speak with their doctor before using this
method. Relying on this type of treatment alone, and avoiding conventional medical care, may
have serious health consequences.
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References
Cassileth B. The Alternative Medicine Handbook. New York, NY: W. W. Norton & Co; 1998.
Dale PS, Tamhankar CP, George D, Daftary GV. Co-medication with hydrolytic enzymes in
radiation therapy of uterine cervix: evidence of the reduction of acute side effects. Cancer
Chemother Pharmacol. 2001 Jul;47 Suppl:S29-34.
Gonzalez NJ, Isaacs LL. Evaluation of pancreatic proteolytic enzyme treatment of
adenocarcinoma of the pancreas, with nutrition and detoxification support. Nutr Cancer.
1999;33:117-124.
Green S. Nicholas Gonzalez treatment for cancer: Gland extracts, coffee enemas, vitamin
megadoses, and diets. Scientific Rev Alt Med. 1998;2(2):25-30. Available online at:
www.quackwatch.org/01QuackeryRelatedTopics/Cancer/kg.html. Accessed June 2005.
Gujral MS, Patnaik PM, Kaul R, Parikh HK, Conradt C, Tamhankar CP, Daftary GV. Efficacy of
hydrolytic enzymes in preventing radiation therapy-induced side effects in patients with head and
neck cancers. Cancer Chemother Pharmacol. 2001 Jul;47 Suppl:S23-28.
Martin T, Uhder K, Kurek R, Roeddiger S, Schneider L, Vogt HG, Heyd R, Zamboglou N. Does
prophylactic treatment with proteolytic enzymes reduce acute toxicity of adjuvant pelvic
irradiation? Results of a double-blind randomized trial. Radiother Oncol. 2002 Oct;65(1):17-22.
Sakalova A, Bock PR, Dedik L, Hanisch J, Schiess W, Gazova S, Chabronova I, Holomanova D,
Mistrik M, Hrubisko M. Retrolective cohort study of an additive therapy with an oral enzyme
preparation in patients with multiple myeloma. Cancer Chemother Pharmacol. 2001 Jul;47