Diet and food supplements

You may make changes to your diet to improve health, or cope with the effects of cancer and its treatment. Following a healthy, balanced diet is one of the most important changes you can make.

Dietary supplements can be helpful for people who are not able to get all the nutrients they need from their diet. This might be because of eating problems or because their bodies can’t absorb the nutrients. But there is not enough evidence to suggest that taking dietary supplements can help treat cancer or stop it from coming back.

Always speak to your doctor before taking any dietary supplements. Some supplements, for example antioxidants, can affect how well your cancer treatment works. Some may even increase the risk of some cancers.

If you have eating or weight problems you may be referred to a dietitian. Dietitians use medical evidence to give advice. They are regulated by law. Nutritional therapists are not regulated by law, although some may be qualified to give information about healthy eating. There is no medical evidence that nutritional therapy can improve health or reduce the risk of cancer coming back.

Cancer and your diet

Many people make changes to their diet after a cancer diagnosis as a way of staying as healthy as possible. They may also do this to help their body cope with the effects of cancer and its treatments. The most important changes people can make for their health are:

For most people, making these types of changes will make the biggest difference to their health. They can be more helpful than making any one particular change.

People often ask their doctor about ‘superfoods’ or foods that boost the immune system. But there isn’t any medical evidence that suggests these work. Eating a wide range of foods that have the vitamins and minerals your body needs will have the most benefit.

There still isn’t enough clear information to make exact recommendations about what someone with cancer should eat. This is because each person’s needs are different. In general, cancer experts recommend following a healthy, balanced diet. Your healthcare team (this includes your GP, doctors, nurses and dietitian) are the best people to advise you what lifestyle changes you could make that may help.

We have more information about healthy eating and cancer, including a useful video with tips for healthy eating.

If you are underweight or find it difficult to eat enough to maintain your weight, then following a healthy eating diet is not recommended. Ask your doctor to refer you to a dietitian for specific advice.


Dietary supplements

For our bodies to work properly, we need nutrients, such as vitamins, minerals, protein, fat, carbohydrate and fibre.

The best way to get these is by eating a healthy, balanced diet. However, some people with cancer are not able to get all the nutrients they need from their diet. This may be because of problems with eating or because their bodies can’t absorb the nutrients.

If you are concerned about your diet or nutrition, ask your doctor or nurse to refer you to a dietitian. They can give you advice on what to eat and may prescribe nutritional supplements for you.

If you are not able to eat a healthy balanced diet, your doctor may prescribe a daily multi-vitamin and multi-mineral supplement. This will give you the recommended daily allowance (RDA) of the nutrients you need.

If you are thinking of taking dietary supplements, it is important to talk to your cancer doctor first.

Some people think that if something is good for you in small amounts, taking larger amounts is even better. But this isn’t always the case. Nutrients are essential for our health in small amounts. But they be can be harmful and cause unpleasant side effects when taken in large amounts. And some may interact with cancer treatments or lessen the effectiveness of them.

Despite a lot of research into cancer and dietary supplements, there isn’t enough evidence to suggest that taking them can help treat cancer or stop it from coming back. But research has found that taking certain supplements could increase the risk of some cancers developing. Talk to your cancer doctor or nurse if you are thinking of taking supplements.


Antioxidants

Antioxidants, such as vitamins A, C and E, coenzyme Q10 and selenium are some of the most commonly taken dietary supplements.

Always tell your cancer doctor if you are thinking of taking antioxidants. Antioxidants can help to prevent cell damage. Because of this, some doctors have concerns that taking antioxidant supplements during cancer treatment may make cancer treatment less effective. Your cancer doctor may recommend that you don’t take antioxidant supplements during your treatment, unless it is as part of a clinical trial.

If you would like to discuss dietary supplements and get more information, you can contact us.


Dietitians and nutritional therapists

Dietitians use current medical evidence to give specific advice to people with eating or weight problems. They also give advice on healthy eating in general. Some dietitians have specific training in helping people affected by cancer. Dietitians are regulated by the law and must meet a national standard of practice.

Nutritional therapists are different from dietitians. Some nutritional therapists may be qualified to provide information on healthy eating, but they are not regulated in the same way as dietitians. Some nutritional therapists may try to improve your health using methods such as ‘detoxing’, suggesting you take high-dose vitamins or avoiding certain food groups, such as sugar. These types of diets are not recommended for people with cancer.

There is no medical evidence that nutritional therapy can reduce the chance of cancer coming back. No reliable research has shown that nutritional therapy can improve health.