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Therapies based on diet

It’s common for people with cancer to have questions about what to eat during and after treatment. People often consider changing their diet to help their body cope with the effects of cancer and its treatments, and to give themselves the best chance of recovery. Some complementary therapies incorporate general dietary advice, while others have their own specific approaches to diet.

Benefits: Good nutrition before, during and after treatment can help you cope better with side effects, increase energy and maintain wellbeing. Vegetables and fruit contain vitamins, minerals and phytochemicals – natural substances such as antioxidants that may destroy cancer-causing agents (carcinogens). While it’s best to get vitamins and minerals from eating whole foods, they are sometimes taken as supplements. If you were taking supplements before treatment, ask your oncologist if you can continue.

Side effects: Some people claim that a particular diet can cure or control cancer on its own. However, there are no special foods, diets or vitamin and mineral supplements that have been scientifically proven to do this.

Unproven diets, particularly those that suggest cutting out whole food groups, are likely to be low in energy (kilojoules/calories), protein, fat, iron, calcium, zinc and vitamins. Following one of these diets can cause unwanted weight loss and tiredness, and lower your immune function. Cutting out whole food groups and losing weight may also contribute to malnutrition. This may make it harder for you to cope with treatment and may slow down your recovery.

Download our booklet ‘Nutrition and Cancer’

What it is: Cancer Council recommends people with cancer follow the Australian Dietary Guidelines, which give advice on what you need to eat and how much. The guidelines recommend eating a wide variety of foods from all five food groups every day:

  • plenty of vegetables of different types and colours, and legumes/beans
  • fruit
  • grains, mostly wholegrains, such as breads, cereals, rice, pasta, noodles, polenta, couscous, oats, quinoa and barley
  • lean meats and poultry, fish, eggs, tofu, nuts and seeds, and legumes/beans
  • milk, yoghurt, cheese and/or alternatives – mostly reduced fat.

Why use it: A balanced diet will help keep your body healthy and contribute to your wellbeing.

What to expect: For some people, it is not always possible to eat well during treatment. You can work with an Accredited Practising Dietitian who can ensure you meet your nutritional needs, give you tailored advice on your nutrition and coping with any eating problems you may experience, and assist in managing side effects.

Evidence: There is clinical evidence to show that eating a healthy, balanced diet can reduce people’s cancer risk and help people recover from cancer treatment.

What it is: This is part of a broad field of health care that focuses on the foods you eat and how they affect your health and wellbeing. This approach recognises the role of food as medicine and that the nutritional needs of each person are different.

Why use it: A diet tailored to your unique needs and your body’s specific requirements may help you achieve optimal health.

What to expect: A naturopathic nutritionist develops a treatment plan that is focused on a diet of nutrient-rich food. You will be encouraged to avoid or limit artificial flavours and chemicals. You may also be prescribed specific herbs or supplements.

Evidence: Clinical evidence supports the use of a healthy diet for good health.

During treatment some people follow a restricted diet, which may stop  them getting enough nutrients for their body to work properly.

Gerson therapy – This involves drinking fresh juice several times a day, taking supplements, and having coffee enemas. There is no scientific evidence that Gerson therapy is an effective treatment for cancer, and evidence shows that coffee enemas can be dangerous if used excessively.

High doses of vitamins – Some people believe that taking high doses of certain vitamins will strengthen the body’s immune system during cancer treatment. However, there is little evidence to support this claim. In fact, many vitamins and minerals can be toxic at high levels, and may affect how chemotherapy, radiation therapy and other medicines work.

Alkaline diet – This diet claims eating high alkaline foods such as green vegetables, fruits, oily fish and nuts lowers the acidity levels in the body. A low acid level is said to stop cancer growth, but there’s no evidence to support this claim.

Macrobiotic diet – Generally, this diet consists of wholegrains, fruits and vegetables, and soups made with legumes and fermented soy (miso). This diet may cause you to lose weight. There is no evidence this diet cures cancer.

Keep your complementary therapists and other health professionals informed about any special diets you try before, during or after cancer  treatment. Being informed about your diet will help them give you the best possible care. 

This information is reviewed by

This information was last reviewed April 2018 by the following expert content reviewers: Suzanne Grant, Senior Acupuncturist, Chris O’Brien Lifehouse, NSW; A/Prof Craig Hassed, Senior Lecturer, Department of General Practice, Monash University, VIC; Mara Lidums, Consumer; Tanya McMillan, Consumer; Simone Noelker, Physiotherapist and Wellness Centre Manager, Ballarat Regional Integrated Cancer Centre, VIC; A/Prof Byeongsang Oh, Acupuncturist, University of Sydney and Northern Sydney Cancer Centre, NSW; Sue Suchy, Consumer; Marie Veale, 13 11 20 Consultant, Cancer Council Queensland, QLD; Prof Anne Williams, Nursing Research Consultant, Centre for Nursing Research, Sir Charles Gairdner Hospital, and Chair, Health Research, School of Health Professions, Murdoch University, WA.