After your cancer diagnosis it is understandable that you or your friends and family will want to research what may help you at this time. Dietary advice can be confusing, and sometimes it is difficult to know what to do.

Many people go on the internet to look for answers but some websites do not provide reliable information. Not all of the information has been adequately researched so would not be advised by your healthcare professionals.

A registered dietitian is the only nutritionally qualified professional that can provide reliable advice on diet and nutrition related problems.

We would not recommend any unnecessary restrictions on your diet as this may affect your quality of life, ability to tolerate treatment and make your diet unpalatable.

There are many different diets out there which claim to help prevent or cure cancer. Some of these diets are harmful and could affect the way your treatment works.

In this leaflet, we outline some of the most common alternative diets we are asked about.

Sugar free diets

All the food that you eat can be broken down into energy. The energy source that our bodies use is a sugar called glucose.

All the cells in our body, including the cancer cells need glucose to survive. Cancer cells are the fastest growing cells in our body therefore they will use up more glucose.

Even if you cut out sugar in your diet, our bodies will find glucose from somewhere else. Your body can break down protein and fat to make the glucose it needs for energy.

Cutting sugar out of your diet will therefore have no effect on cancer growth. It will restrict what you eat, make your diet unpalatable and could lead to weight loss.

Dairy free diets

Some people think that there is a link between eating dairy foods and some cancers, however this has not been proven. There is evidence that calcium may help reduce the risk of bowel cancer.

Dairy products include milk, cheese, butter, yoghurt, ice cream, cream, buttermilk and kefir.

Dairy products are one of the main food groups in the western diet. They are the main source of calcium and provide energy, protein, vitamins and minerals.

Milk is generally tolerated well especially for those finding eating and drinking difficult.

If you decide to follow a dairy free diet we recommend you use suitable dairy free calcium enriched alternatives.

If you choose to use soy products in place of dairy they are safe to eat as part of a healthy diet. However, at this stage there is no proof to show that they help prevent cancer or recurrence of cancer.

Organic food

Organic food is produced without the addition of chemical fertilisers, pesticides or additives.

Some people think organic food tastes better, is more ethical, environmentally friendly and supports the local economy. However, it is more expensive.

Studies that have examined the nutritional benefits of organic fruit and vegetables have had mixed results.

So far, research has not shown that an organic diet is more effective at stopping the occurrence or recurrence of cancer compared to a non-organic diet. It is therefore your choice if you choose to eat organic foods.

Vitamin, mineral and herbal supplements

Many people take supplements on a daily basis for a variety of reasons. If you are eating a balanced diet you should be getting enough vitamins and minerals from your food.

If you are not eating enough food, your healthcare professional may recommend that you take a daily multivitamin and mineral supplement to meet your needs. However, taking herbal supplements or large doses of vitamin or mineral supplements would not be recommended during oncology treatment. These can be harmful during your oncology treatment as they can interfere with how the treatment works.

It is important to talk with your healthcare professional about any supplements you are taking.

Probiotics

Our gut is teeming with bacteria. There is a balance of beneficial and harmful bacteria.

Probiotics are the good bacteria in the gut. Sometimes the levels of probiotics can be affected if you have been on antibiotics or have had surgery to your gut. Some people take a probiotic supplement such as Yakult or Actimel, to help restore and maintain the balance of bacteria in the gut.

The British Dietetic Association recommends that people having chemotherapy avoid products labelled as having probiotic bacteria in them. This approach is endorsed by the manufacturers themselves.

Live yoghurts are not potentially harmful and no restriction is necessary. This is because the starter cultures are not probiotic bacteria and cannot survive in the human stomach.

Unless a product specifically refers to its probiotic content such as “bio” then no restriction is necessary.

If you are unsure, ask to speak with a dietitian.

Superfoods

“Superfood” is a term banned in EU and UK law. It is used as a marketing tool and is used to promote a food which is supposedly rich in nutrients and beneficial to health. They can often be expensive.

There are many substances in fruit and vegetables that may have anti-cancer properties. At the moment we don’t know this for certain and we don’t understand which ones are most likely to help or how they work.

No single food will keep us healthy and it is better to eat a variety of foods to make sure you get all the right nutrients you need.

If you focus on eating one particular food it can mean you could miss out on other nutrients that you need. It is okay to have a “superfood” in normal quantities as part of a varied diet.

Alkaline diet

The theory behind the alkaline diet is that cancer cells work in an acidic environment and if we can change the pH of our body to become alkaline we can stop the cancer growing.

This theory has no scientific basis. Changing your diet will not alter the pH balance of your body.  The pH of your body is strictly regulated by your organs.

We do not recommend trying the alkaline diet as it will not work and can be harmful to your health.

Recommended websites

British Dietetic Association

www.bda.uk.com

Cancer Research UK

www.cancerhelp.org.uk

Macmillan

www.macmillan.org.uk

World Cancer Research Fund

www.wcrf-uk.org/