There are often stories in the media about certain foods or nutrients in the cancer diet that will
- increase the risk of cancer
- decrease the risk of cancer
- feed cancer
- cure cancer
It is beyond the scope of this article to discuss fads, hoaxes, current research or scientific evidence. Except to say the obvious, that not everything you read, especially on the internet is true. The best way to avoid hoaxes and common cancer myths is to look at
- Current official guidelines
- Specific cancer treatments and their likely side effects on the cancer diet
Official recommendations for the ideal cancer diet
It is clear that having a healthy cancer diet can help people cope better with both treatment and the illness. However, there is a caveat to this. Both treatment and cancer symptoms can have nutrition-related side effects, as discussed below.
How cancer symptoms can affect a healthy diet
Different people are diagnosed at different stages of cancer and different types of cancer can produce different symptoms. Generally speaking, most people who have cancer are advised to eat a healthy diet. In some cases, a high-calorie diet is recommended. This is because weight loss can be a problem and a high-calorie diet keeps energy levels up during treatment. However, in the majority of cases, a normal healthy diet will be good enough.
How treatment can directly affect the cancer diet
It is important to recognise that some foods and supplements can counteract cancer treatments, so it is very wise to let your doctor or pharmacist know of any supplements you might be taking or any dietary changes.
A common herbal remedy taken at times of stress can be St John’s wort, which is used as a complementary therapy for mild to moderate depression. But it also interacts with several cancer medicines, such as tamoxifen, irinotecan, docetaxel and imatinib.
Grapefruit, although often recommended for a healthy diet can increase and decrease the potency of many cancer drugs.
How treatment can cause symptoms which affect the cancer diet
Many of the diets issues that cancer patients have are due to the side effects of the therapy they are having.
These may cause
- loss of appetite
- taste changes
- mouth problems
- diarrhoea and/or constipation
Suggestions to help with cancer-related diet issues
Loss of appetite
When cancer treatment causes weight loss and loss of appetite there are a number of things to do
- Don’t fill your stomach with a large amount of liquid before eating.
- Eat small amounts of high protein and calorie foods every 2 or 3 hours.
- Ask friends and relatives to help prepare your meals.
- Add extra calories and protein to the food that you eat such as using butter, milk, cream, sugar, honey and cheese.
- Eat cold or slightly warm food if the smell of cooking puts you off eating.
- Have small servings of your favourite foods prepared ahead of time.
- Keep a stock of convenience foods in the cupboard.
- Eat puddings and desserts.
- Try new foods and tastes.
- Avoid getting overtired.
- Stay hydrated, drink a lot of water.
Don’t give yourself a hard time if you don’t want to eat much for a few days after treatment.
Diarrhoea is a common side effect of some cancer treatments. Here are some diet changes you can make to cope
- Drink plenty of liquid (up to two litres a day) to replace fluid lost.
- Avoid alcohol and coffee.
- Small, frequent meals made from light foods such as dairy produce, white fish, poultry, well-cooked eggs, white bread, pasta or rice can help
- Eat meals slowly.
- Avoid greasy and fried food
- Eat less fibre until the diarrhoea improves.
- Avoid spicy food
Cool drinks may soothe a sore mouth, but avoid hot (spicy) or sharp foods, as these can sting your mouth.
- Drink plenty of fluids using few but frequents sips
- Have 5 or 6 small meals a day
- Stay away from fried, spicy, sweet, or salty foods.
- Peppermint and ginger can both help with nausea. This can be in any form such as teas or sweets
Some drugs can cause constipation, particularly painkillers, but also some chemotherapy drugs. Mild laxatives which you can get from your doctor can help. It can also help to drink plenty of fluids and eat as much fresh fruit and vegetables as you can.
Small diet changes can make a huge difference, and the above suggestions can help, but it is always important to let your doctor know if you have any symptoms which are bothering you and if you make any dietary changes or are thinking of taking supplements.
Related articles about the cancer diet
Dr Cohen started her working life as a research scientist and lecturer with over 100 peer-reviewed scientific publications.
She followed a classical scientific career until she left mainstream science in 2000 (which coincided with the birth of her first daughter) to establish the Life Science Communications company, Euroscicon Ltd.
Euroscicon Ltd was her first company (which she sold in 2016).
In 2013 Dr Cohen was diagnosed with Cancer and set up Cancer Care Parcel which provides appropriate gifts for people with cancer.
Dr Cohen is the lead scientific advisor at Optimised Healthcare. A medical profiling company which provides advanced disease prediction, prevention and wellness optimization services.
She also works with and establishes businesses and charities which benefit local, national and international communities.