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The safety of metabolic therapy and alternative diets

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This page tells you about metabolic therapy and alternative diets sometimes used by people with cancer. There is information about


Metabolic therapy and alternative diets

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


Types of alternative therapy diets

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

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

The different types of metabolic therapy vary a lot but they are all based on special diets and practices that aim to detoxify the body.


What metabolic therapies may 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 use may 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 has shown that a healthy, well balanced diet can reduce the risk of cancer. We have information about diet, healthy eating and cancer

People who promote alternative diets often make claims 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 very restrictive and strict so that it is 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 cancer in particular groups of 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. So, if you are thinking of trying an alternative diet, it is very important to talk to a dietician and go through the diet with them. They will be able to advise you about how safe it is for you. Your hospital doctor or specialist nurse should be able to arrange for you to see a dietician.


Alternative practitioner views on conventional medicine

Some practitioners who promote alternative diets and therapies say that conventional medicine does you more harm than any alternative treatment. 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. 

The dose of conventional cancer treatments is very carefully controlled. So they have been shown to cure or control cancer in some people. And your doctors will be very open with you about the side effects and drawbacks of any conventional cancer treatment they offer you.

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Updated: 24 October 2014