Metabolic Therapies

August 18, 2009
Barrie R. Cassileth, MS, PhD

Oncology, ONCOLOGY Vol 23 No 9, Volume 23, Issue 9

Promoters of metabolic therapies claim that special diets, detoxification, and immune stimulation can treat and prevent a variety of diseases including arthritis, multiple sclerosis, and cancer.

Advocates claim that cancer and other diseases result from an accumulation of toxins that disrupt the immune system and cell metabolism. The removal of these toxins through bowel purging and a healthy diet, they claim, allows the body to heal naturally. However, there is no convincing clinical evidence to support any of these therapies. Well designed studies are still needed to evaluate metabolic therapies.

The strict dietary recommendations of some metabolic therapies can cause nutritional deficiencies, while some entail potentially toxic doses of supplements or agents. Excessive use of coffee enemas used for detoxification can cause sepsis and dangerous electrolyte deficiencies, especially when combined with fasting.

Cancer patients should be especially cautious, as abandoning timely and effective treatments in pursuit of questionable alternatives such as metabolic therapies can be detrimental.

TREATMENT: Metabolic therapies

ALSO KNOWN AS: Nutritional therapies, Gerson regimen, Kelley therapy, Gonzalez regimen, Contreras therapy, Manner therapy

USES: Detoxification, cancer prevention, and cancer treatment.

SUMMARY: Metabolic therapies, offered in the US, Mexico, and elsewhere are based on the theory that cancer and other diseases are caused by an accumulation of toxic substances in the body. Proponents claim that a healthy diet, detoxification, and immune augmentation allow the body to heal naturally. Diet is often based on whole foods and fresh fruits and vegetables, and is supplemented by digestive enzymes, glandular extracts, megadose vitamins, minerals, or herbal products. Agents such as interleukins, hydrazine sulfate, hydrogen peroxide, or laetrile also may be administered. Detoxification includes colonic irrigation with coffee or hydrogen peroxide enemas and herbal laxatives.

A small uncontrolled study in 1993 found increased survival in patients with pancreatic cancer after oral administration of large amounts of pancreatic enzymes,[1] following which the ­NCCAM sponsored a randomized study of the Gonzalez regimen vs gemcitabine in patients with stage II–IV pancreatic adenocarcinoma.[2] Results have not yet been published. Long-term follow-up of cancer patients using Gerson, Kelley, and Contreras therapies showed no evidence of efficacy.[3]

ADVERSE REACTIONSCommon: Flu-like symptoms, nausea, vomiting, diarrhea, weakness, dizziness, intestinal cramping, fever, muscle aches and pains, rashes. Nutrient deficiencies (calcium, vitamins D and B12, protein), anemia, and malabsorption may result from metabolic therapies.[4]

Reported (coffee enemas): Electrolyte imbalance leading to serious infections, dehydration, colitis, constipation, and death. Perforation or rupture of the colon from hard insertion devices and transfer of pathogenic microorganisms by contaminated devices were also reported.[5]

 Case Reports (coffee enemas): Case 1: Multiple seizures and hypokalemia leading to cardiorespiratory arrest, coma, and death were reported after excessive use of coffee enemas (1–4 per hour) for several days. Case 2: Death was attributed to fluid and electrolyte imbalance causing pleural and pericardial effusions following use of coffee enemas (4 per day for 8 weeks).[6]


1. Gonzalez NJ, Isaacs LL: Evaluation of pancreatic proteolytic enzyme treatment of adenocarcinoma of the pancreas, with nutrition and detoxification support. Nutr Cancer 33:117-124, 1999.
2. American Cancer Society: Metabolic therapy. Available at
3. Austin S, et al: Longterm followup of cancer patients using Contreras, Hoxsey and Gerson therapies. J Naturopathic Med 5:74-76, 1994.
4. Questionable methods of cancer management. CA Cancer J Clin 41:310-319, 1991.
5. Green S: A critique of the rationale for cancer treatment with coffee enemas and diet. JAMA 268:3224-3227, 1992.
6. Eisele JW, Reay DT: Deaths related to coffee enemas. JAMA 244:1608-1609, 1980.