What should you eat while you're being treated for cancer? - Cancer Research UK

Can certain diets help with cancer treatment?

In the years we’ve been writing this blog, we’ve published scores of articles looking at how different types of food and drink do or don’t influence a person’s chances of developing cancer. By now everyone should be familiar with our basic advice (and how this topic is frequently misreported in the media).

But we’ve only occasionally touched on what for many of our readers is a much more pressing issue – what to eat when you already have cancer.

This isn’t deliberate; indeed, there’s a very good reason for this: the scientific evidence is much less solid, and it’s very difficult to say anything concrete.

Tonight, Channel 4 airs the first of a new series called The Food Hospital, which will “examine the science behind using food in medicine, tackling patients’ health problems through the food they eat”, according to the accompanying blurb.

To mark the series’ launch, we thought it would be good to highlight some of the online information we have about diet and cancer, and briefly discuss what the evidence does – and doesn’t – say.

There are two main reasons people change their diet when they have cancer – to help with side effects, and to try to influence how their disease progresses or improve how treatments work.

Helping with side effects

On the first point – managing side effects – there’s a fair amount of evidence that your diet can be helpful. People who have cancer are generally advised to eat a high-calorie diet, as weight loss can be a problem and it keeps your energy levels up during treatment.

The type of cancer you have – and the way it is being treated – also influences the best approach to take with your diet. So someone with a sore mouth would get different advice to someone having bowel problems following radiotherapy to the abdomen.

Can diet help beat cancer?

On the second point – trying to influence the outcome of your cancer – there’s more myth and rumour than hard evidence. Some extreme examples, touted as alternatives to conventional therapy, are completely unsupported by scientific evidence and can be dangerous.

Other diets and foods are pretty much harmless but can cost a lot and, again, claims they’re helpful are not based on much more than anecdote.

And finally, there are some common foods, for example, grapefruit juice, than can interfere with treatments.

Below, we’ve listed some of the relevant articles on CancerHelp UK, our award-winning patient information website. But our central message is this – beware of claims that any particular food can treat your cancer, and always – always – discuss things with your specialist if you’re considering a special diet.

● Our main section on diet

● Information on specific complementary/alternative therapies

● Can diet on its own stop bowel cancer growing?

● Can changing what I eat help me recover from my cancer?

● What should I eat during chemotherapy?

● Can I use diet to help my hot flushes while I am taking tamoxifen?

● Why has my doctor told me not to eat or drink some foods or take certain drugs with my cancer treatment?

● There’s also a cancer-specific section on diet in some of the different types of cancer on CancerHelp UK, for example, bowel cancer and stomach cancer – to find them, go to the ‘Your cancer type’ page, select the cancer you’re interested in, and have a look in the ‘Living with’ section.

There’s a lot of misinformation out there, and trying to find sound advice on how to eat can be tricky, especially at such a difficult time. If you have any questions about this, you can contact our Information Nurses, either online or on freephone 0808 800 4040, 9am – 5pm Monday to Friday. And on our Cancer Chat forum you can talk to others affected by cancer and share your experiences.

Henry