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The safety of metabolic therapy and alternative diets

Learn about metabolic therapy and alternative diets which some people with cancer might use.

Metabolic therapy and alternative diets

Metabolic therapy tries to remove harmful substances from the body (toxins) and strengthen the body's resistance to illness. It uses a combination of special diets, enzymes, nutritional supplements and other practices.

In the UK the best known metabolic therapies are Gerson therapy and macrobiotic diets. But there are many other types, including:

  • Kelley's treatment
  • Gonzalez treatment
  • Issels whole body therapy
  • Contreras metabolic therapy
  • injecting live cells from animals (cell therapy)

What metabolic therapies might involve

The special diets usually involve natural, whole foods such as fresh fruits and vegetables, as well as vitamin and mineral supplements. Some include laetrile, a plant substance that can cause severe side effects for some people.

Other practices that the therapies might use include:

  • bowel washouts (colonic irrigation) with coffee or hydrogen peroxide enemas
  • enzyme therapy
  • removal of dental fillings
  • visualisation
  • psychological therapy
  • stress reducing exercises

Metabolic therapies and cancer

Research shows that a healthy, well balanced diet can reduce the risk of cancer.

People who promote alternative diets often claim that they will cleanse your body, stimulate your metabolism, boost your immune system and fight your cancer.

But there is no evidence that any type of metabolic therapy or alternative diet can prevent, treat or control cancer. In fact, some of the therapies and diets are strict and restrictive. So it's impossible to get the right balance of nutrients. This can be a serious risk to your health if you are already weakened by cancer or by treatments such as chemotherapy, biological therapy or radiotherapy.

Some small research studies seem to show that some types of nutritional supplement (such as coenzyme Q10) may help to control advanced cancer in some people. But we need bigger studies to confirm this.

Some treatments used in metabolic therapies can cause harm. For example, coffee enemas carry a risk of causing a chemical imbalance in the body. And some nutritional supplements can be harmful in high doses.

Talk to a dietitian and go through the diet with them if you're thinking of trying an alternative diet. They will be able to advise you about how safe it will be for you. Your hospital doctor or specialist nurse should be able to arrange for you to see a dietitian.

Alternative practitioner views on conventional medicine

Some people and companies who promote alternative diets and therapies say that they are less harmful than conventional medicine. It is true that conventional cancer treatments, such as radiotherapy and cancer drugs, damage normal cells. The damage causes side effects. But these treatments have been tested in strictly monitored trials and have been proven to kill cancer cells.

Your doctor will tell you about all the side effects and drawbacks of any conventional cancer treatment they offer you, as well as the benefits.

Last reviewed: 
24 Oct 2014
  • Oxford Textbook of Palliative Medicine (3rd edition)
    D Doyle, G Hanks, N Cherny and K Calman
    Oxford University Press, 2005

  • Improved survival in patients with end stage cancer treated with coenzyme Q10 and other antioxidants: a pilot study
    N Hertz and RE Lister
    Journal of International Medical Research, 2009. Volume 37, Issue 6

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