Cancer and eating well
Eating well means having a range of foods to get all the nutrients and fibre your body needs. The five main food groups are:
- fruit and vegetables
- starchy foods including bread, pasta, rice and potatoes
- dairy and alternatives
- meat, fish, eggs, beans and other sources of protein
- oils and spreads
When you have cancer, your treatment and the cancer can affect your diet and ability to eat. The cancer can affect how your body uses and processes food – even if you are eating, you may still lose weight.
Treatment side-effects, such as feeling sick or a sore mouth can also make it hard for you to eat and drink as much as you need to. This can be a particular problem if you have already lost weight before you were diagnosed. Your diet may need to change while you’re having treatment. For example, radiotherapy and chemotherapy can cause diarrhoea, so you may be advised to eat a low-fibre diet to help control it.
For more tips on how to manage your diet during treatment, see our section on Tips for eating.
Why is eating well important?
Eating well during and after cancer helps:
- make sure you have all the nutrients your body needs
- keep your weight up
- you to cope better with your treatment
- reduce the risk of complications
- you to manage treatment side-effects
- keep up your strength and energy
- reduce your risk of getting an infection
- your body recover and repair itself
- reduce the time you spend in hospital
- improve your quality of life
Keeping your weight up
If you aren’t able to eat enough or are losing weight, you may need more energy (calories) and protein in your diet. To get these extra calories, you might need to eat a diet that wouldn’t normally be recommended when you’re in good health.
To boost the amount of energy you take in from the foods you eat, try choosing high-calorie and high-fat options. Use full-fat milk or cream, plenty of butter or margarine and add sugar to puddings. If you find eating large meals difficult, eat little and often, with several small, high-energy, high-protein snacks throughout the day.
For more help and advice, ask your doctor to refer you to a dietitian. Your hospital may well have a dietitian who is specially trained in looking after people with cancer. They can help you plan the diet that‘s right for you.
You can also get high-energy ‘meal-in-a-drink’ supplements to add extra energy and protein to your diet. They shouldn’t be used to replace food, but may be useful if you find you can’t eat enough food to keep your energy up. As well as milky drinks and juices, supplements can come in the form of powder that you add to food and ready-made puddings too. Your dietitian can advise whether these would be helpful for you. You can buy some of these products from a pharmacy. For others, you may need a prescription – ask your doctor or dietitian about this.
Taking dietary supplements
There’s uncertainty around taking vitamin, mineral and other dietary supplements when you have cancer. Some might even interfere with treatment. If you’re thinking of taking a supplement, speak to your nurse or doctor before you do.
We don’t know how much supplements might interact with cancer treatments. Because antioxidant vitamins and minerals help to stop cell damage, some doctors worry that they may also stop cancer cells being damaged during treatment.
It’s important not to take too much of a supplement, unless advised to by your doctor, as high doses might be harmful to you.
In some circumstances, your doctor may recommend that you take particular supplements. For example, men with prostate cancer and women with breast cancer may need to take calcium and vitamin D supplements to help stop osteoporosis, which can be a side-effect of treatment. Taking a multivitamin daily may be suitable for you if you’re finding it hard to get all the nutrients you need through food alone. Talk to your healthcare team for more information.
Tips for eating
There are many ways to help yourself enjoy your food and eat well if you have cancer. Here are just a few tips.
If you’re tired:
- eat what you want when you feel like it – you don’t have to stick to meal times
- batch cook to fill up your fridge and freezer with home-cooked ‘ready meals’ – or get a friend or relative to cook and freeze meals for you
- stock up on convenience foods that are quick to prepare or buy healthy ready meals
If you have no appetite:
- eat little and often – instead of eating three large meals, try eating five or six small portions of food each day
- keep snacks handy for when you feel like eating
- add hidden calories to your meals with high-fat foods – for example, add cream, cheese, butter or honey
- add protein to full-fat milk with a couple of tablespoons of milk powder and use in drinks and cooking
- blend nutritious smoothies with fresh fruit, yoghurt and ice cream to sip when you can’t face a meal
If you feel sick:
- avoid fried and fatty foods, or those with a strong smell – try bland food like crackers or plain toast
- try eating foods or drinks that contain ginger, such as a ginger biscuit or ginger tea
- sipping on cold fizzy drinks may help
- don’t lie down after eating
- try eating meals at room temperature and keeping foods and drinks covered – this might help to tone down any smells that might be putting you off your food
If food and drink tastes odd:
- choose foods that look and smell good to you
- try adding extra flavours, like herbs, spices, garlic or lemon juice
- try lemon tea, or cold fizzy drinks, if you’ve gone off hot drinks with milk
- try using plastic cutlery – this may help if you have a metallic taste in your mouth
If your mouth is sore or dry, or you have trouble swallowing:
- take a sip of water and swish it around your mouth to help refresh it
- blend foods so that they are easier to swallow (or finely chop if you prefer to still have some texture)
- for savoury meals, try soups, stews, dahls and mince-based meat dishes with a lot of sauce or gravy
- choose soft desserts, including rice pudding, ice cream, mousses and jellies – add cream to pack in calories
- you may find that spicy, salty and sharp tasting foods can make a sore mouth worse and are best avoided
If symptoms from your treatment are making it difficult for you to eat and drink, speak to your doctor. They can give you advice and prescribe medicines to help you cope. These include anti-sickness medicines, and artificial saliva to help combat dry mouth. Your doctor can also refer you to a dietitian if you need some extra help.
Your body needs plenty of liquid to replace what you lose each day. When your body doesn’t have as much water as it should, you become dehydrated. If you have cancer you may be at risk of dehydration because you have vomiting, diarrhoea or a sore mouth as a side-effect of your treatment. As well as feeling thirsty, dehydration can cause dizziness, weakness, dry mouth and skin. You won’t pass as much urine as usual and may notice that your urine is darker than normal. As a basic guide, most people need between 1.5 and 2.5 litres of fluid each day (between six and 10 mugs), depending on their age, sex and activity. It doesn’t have to be water – squash, soups, milk and juices all count.
It’s well known that alcohol can increase the risk of developing some types of cancer, including mouth, breast, oesophagus and bowel cancer. But there isn’t enough evidence that it can increase the risk of cancer coming back if you already have it.
A few chemotherapy drugs are affected by the amount of alcohol you drink, and their side-effects might be worse if you drink. Alcohol also irritates the lining of the mouth and is best avoided if you have sores caused by some cancer treatments.
If you don’t feel like eating, a small amount of alcohol might increase your appetite. But it’s important not to drink if you’re taking certain medicines, so check with your doctor first.
Your cancer treatment can also increase your risk of other conditions such as osteoporosis. Alcohol affects the body’s calcium balance and vitamin D production, so can further increase your risk of getting osteoporosis.
Always speak to your doctor before drinking alcohol if you’re taking medicines or having treatment for cancer. For people who have finished their treatment, we don’t know if alcohol can increase the risk of cancer coming back, but it could increase the risk of developing another cancer. Do speak to your doctor, who will be able to talk this through with you.
There’s a lot of information out there about different diets and their effects on cancer. Alternative cancer diets include Gerson therapy, macrobiotic diets and Issel’s therapy. Other approaches tell you that making your diet less acidic will help to prevent or treat cancer. Or that banning sugar will stop ‘feeding’ the cancer.
There’s no proof that any of these approaches can help to prevent, treat or cure cancer. Some can even do harm because you won’t get all the nutrients you need to keep healthy.
The best thing is to eat a healthy, balanced diet. You may have particular diet requirements while you are having treatment or recovering. Your dietician can help you to tailor your diet so that it meets all your needs.
Your diet after cancer
When your treatment first ends, you may still have difficulties with eating and drinking. Sometimes, the effects of treatment last for quite a while or even come on after your treatment has finished. You may, for example, find that things no longer taste the same. The types of problems and how long they last depend on the type of cancer and treatment you had. Do speak to your doctor or nurse if you’re having problems. They can offer you advice or refer you to a dietitian who will be able to give you further practical advice and support if needed.
Many people want to know what they should eat to help stop their cancer from coming back. We simply don’t know enough yet to recommend a specific diet. After cancer, doctors generally advise people to eat a healthy, balanced diet and keep within the recommended weight range for their height and build. Maintaining a healthy weight is really important; not only does being overweight affect your overall health, but may also impact on your risk of cancer coming back. If you need to lose weight, it’s important that you lose weight safely. This involves losing weight gradually and focusing on both diet and physical activity levels. You can learn more about getting active in our Exercise – getting started page.
It’s not always easy to achieve or maintain a healthy weight after cancer. For example in breast cancer, you may need to continue taking medicines such as tamoxifen, which can cause you to gain weight. For more information on staying healthy and well after cancer treatment, speak to your doctor or dietitian and always follow their advice.
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Reviewed by Laura Blanks, Specialist Heath Editor, Bupa Health Content Team, July 2017
Expert reviewer Rachael Eden, Dietitian
Next review due July 2020
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