Metabolic Therapies

Metabolic Therapies

Metabolic Therapies

Common Names

  • Nutritional therapies
  • Gerson Regimen
  • Kelley therapy
  • Gonzalez regimen
  • Contreras therapy
  • Manner therapy

For Patients & Caregivers

Metabolic therapies do not treat or cure cancer.

Cancer is caused by a combination of genetic and environmental factors. However, most people who promote metabolic therapies stress the environmental component, claiming that cancer is caused by an accumulation of toxins in the body from sources such as food additives, preservatives, pesticides, and industrial pollution. The removal of these toxins through bowel purging and a healthy diet, they claim, allows the body to heal naturally. Although diet may play a role in cancer prevention and it is true that some cancers are associated with environmental exposures, there are no data to show that toxins can be removed to change the course of cancer. Some aspects of metabolic diets can be harmful. For example, (1) the Gerson regimen restricts the diet to an unhealthy point and can cause nutritional deficiencies, (2) over-supplementation in such diets has led to toxicity and hospitalization, and (3) animal extracts were found to be contaminated.

Coffee enemas are used in several metabolic therapies. There are theories about coffee enemas aiding excretion from the liver and colon, but none of them have been proven. In addition, coffee enemas can cause electrolyte imbalances in the blood and impaired nutrient absorption.

  • To detoxify the body
    No scientific evidence supports this use.
  • To prevent and treat cancer
    Most metabolic therapies have not been evaluated by clinical trials. A recent study of patients with pancreatic cancer showed a decrease in survival time and poorer quality of life in those who took proteolytic enzymes (often used to supplement diet in metabolic therapies), compared with patients who chose standard gemcitabine-based chemotherapy.
  • The American Cancer Society strongly urges cancer patients not to seek treatment with potentially hazardous metabolic/nutritional therapies, including the Gerson, Manner, and Contreras regimens, in Mexican border clinics.
  • Excessive use of coffee enemas can cause infections, dangerous electrolyte imbalances, and death, especially when combined with fasting.
  • Coffee enema insertion devices should not be shared at the risk of transferring bacteria and infections.
  • Flu-like symptoms
  • Nausea, vomiting, diarrhea
  • Weakness, dizziness
  • Intestinal cramping
  • Fever
  • Muscle aches and pains
  • Rash
  • Nutrient deficiencies (calcium, vitamins D and B12, protein), anemia, and malabsorption
  • With coffee enemas: Electrolyte imbalance resulting in serious infections, dehydration, colitis, constipation, and death. Hard enema insertion devices can rupture the colon.

Case reports

  • Two people died from electrolyte imbalances resulting in seizures, coma, and death. One individual used 1–4 coffee enemas per hour for a number of days and the other used 4 per day for 8 weeks.
  • Serious rectal burns were reported in two patients following administration of coffee enemas. Bright red blood in the stool, rectal pain, and pain with defecation resolved after stopping the enemas.
  • Inflamed rectum and colon in a 60-year-old woman after self-administering coffee enema for chronic constipation. Symptoms including bright red blood in the stool, a distressing but ineffectual urge to evacuate the rectum, and spastic anal and low abdominal pain. Symptoms improved following treatment and stopping the enema.
  • Rectal perforation in a 27-year-old woman following the use of coffee enemas. Symptoms improved after discontinuing the enemas.

Eating a balanced diet rich in fiber, fruits, and vegetables is known to be an important part of preventing disease, but there is no proof that diet or supplements can treat or cure cancer. Although controlling one’s diet may create a greater sense of personal control, especially during cancer treatment, the extreme restrictions advocated by proponents of metabolic therapies can be harmful because they lead to severe nutritional deficiencies. In addition, cancer patients run the risk of abandoning effective conventional therapies when they choose to pursue alternative therapies.

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For Healthcare Professionals

As strict dietary and detoxification regimens promoted to prevent and treat cancer and degenerative diseases, metabolic therapies are based on the theory that cancer and other diseases are caused by an accumulation of toxic substances in the body. Advocates claim that a healthy diet, detoxification practices (eg, coffee enemas, herbal laxatives), and immune augmentation detoxify the body and allow it to heal naturally. Therapies such as Gerson, Kelley, Contreras, Manner, and Gonzalez share this ideology but differ in modality. The diets are often based on whole foods including fresh fruits and vegetables, and are supplemented by digestive enzymes, glandular extracts, megadose vitamins, minerals, or herbal products. Agents such as hydrazine sulphate, hydrogen peroxide, or laetrile may also be administered.

Retrospective reviews of the Gerson, Kelley, and Contreras therapies show no evidence of efficacy. Recent findings from a study involving patients with inoperable pancreatic cancer showed a decrease in overall survival and poorer quality of life with proteolytic enzymes, often used to supplement a metabolic therapy diet, compared with standard gemcitabine-based chemotherapy (1).

Although dietary remedies provide a strong sense of personal control, the strict recommendations of some metabolic therapies can cause nutritional deficiencies, while some entail potentially toxic doses of supplements or agents. Coffee enemas can cause sepsis, dangerous electrolyte deficiencies, and death.

The American Cancer Society strongly urges cancer patients not to seek treatment with metabolic therapies.

  • Cancer prevention
  • Cancer treatment
  • Detoxification

Advocates of metabolic therapies claim that cancer and other diseases result from an accumulation of toxins in the body from food additives, preservatives, pesticides, and industrial pollution 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. While diet may play a role in cancer prevention and some cancers are associated with environmental exposures, strict dietary restrictions, as in the Gerson regimen, cause nutritional deficiencies.

Caffeine in coffee enemas is purported to cause dilation of bile ducts, bile production, glutathione S-transferase (GST) activation, and excretion of toxic breakdown products by the liver and through the colon wall. No published evidence supports these claims and no human studies examined the clinical efficacy or physiological effects of coffee enema administration. Kahweol and cafestol are constituents of green coffee that stimulate GST activation, but their activity is destroyed with roasting. Repeated administration of coffee enemas increases extravascular fluid volume and can cause serum electrolyte imbalances. Significant loss of bile salts associated with repeated long-term administration of enemas can result in malabsorption of fat, fat-soluble vitamins, and calcium (2) (3) (4).

  • The American Cancer Society strongly urges cancer patients not to seek treatment with potentially hazardous metabolic/nutritional therapies, including the Gerson, Manner, and Contreras regimens, in Mexican border clinics.
  • Excessive use of coffee enemas can cause infections, dangerous electrolyte deficiencies, and death, especially when combined with fasting.
     (5) (6)

Common: 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 diets (5).

Case Reports (Coffee enemas)

  • Electrolyte imbalance, resulting in serious infections (eg, Campylobacter sepsis and amebiasis), dehydration, colitis, constipation, and death.
  • Perforation or rupture of the colon from hard insertion devices and transfer of pathogenic microorganisms by contaminated devices (4).
  • Multiple seizures and hypokalemia leading to cardiorespiratory arrest, coma, and death after excessive use of coffee enemas (1–4 per hour) for a number of days (2).
  • Death attributable to fluid and electrolyte imbalance causing pleural and pericardial effusions after use of coffee enemas, 4 per day for 8 weeks (2).
  • Serious rectal burns in 2 patients following administration of coffee enemas. Hematochezia, rectal pain, and pain with defecation resolved after stopping the enemas (7) (8).
  • Proctocolitis in a 60-year-old woman after self-administering coffee enema for chronic constipation. Symptoms including hematochezia, tenesmus, and spastic anal pain with lower abdominal pain improved following treatment and cessation of enema (9).
  • Rectal perforation in a 27-year-old woman due to benign stricture caused by rectal burns associated with hot coffee enemas (10).

  1. Eisele JW, Reay DT. Deaths related to coffee enemas. JAMA 1980;244:1608-9.

  2. Josefson D. US cancer institute funds trial of complementary therapy. Western J Med 2000;173:153-4.

  3. American Cancer Society. Questionable methods of cancer management: ’Nutritional’ therapies. Ca: Cancer J Clin 1993;43:309-19.

  4. Sashiyama H, Hamahata Y, Matsuo K, et al. Rectal burn caused by hot-water coffee enema. Gastrointest Endosc. 2008 Nov;68(5):1008; discussion 1009.

  5. Jones LE, Norris WE. Rectal burn induced by hot coffee enema. Endoscopy. 2010;42 Suppl 2:E26.

  6. Keum B, Jeen YT, Park SC, et al. Proctocolitis caused by coffee enemas. Am J Gastroenterol. 2010 Jan;105(1):229-30.

  7. Kim S, Cha JM, Lee CH, Shin HP, et al. Rectal perforation due to benign stricture caused by rectal burns associated with hot coffee enemas. Endoscopy. 2012 Apr;44 Suppl 2 UCTN:E32-3.

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