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 (e.g., coffee enemas, herbal laxatives), and immune augmentation detoxify the body and allow it to heal naturally. Therapies such as the Gerson, Kelley, Contreras, Manner, and Gonzalez share this ideology but differ in modality. 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 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, which are often used to supplement the diet offered by metabolic therapies, compared to 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.