Some nutritional issues need extra care. Speak to your doctor or a dietitian for help managing these issues or call 13 11 20 to speak to a cancer nurse.
Diabetes
Insulin is a hormone that controls the amount of sugar in the blood. A person with diabetes does not create or produce enough insulin or has a resistance to the effects of insulin. This means they need medicines to help control their blood sugar levels.
Side effects and diabetes
Some treatment side effects may make controlling blood sugar levels difficult. These include loss of appetite, nausea, fatigue, constipation and diarrhoea. If you are unable to eat enough, your blood sugar levels may drop too low.
You may need to check your blood sugar levels more often and have snacks that include a variety of carbohydrates. Choose carbohydrate foods that produce a slower rise in blood glucose levels – these are described as having a low glycaemic index (GI). You can also talk to your doctor about changing your dose of insulin or tablets.
Steroids and diabetes
Some medicines, such as steroids, can also cause high or unstable blood sugar levels in people with diabetes. How long the steroids affect your blood sugar levels will depend on the dose and type of steroid you are taking. Steroids given as creams or nasal sprays are unlikely to affect blood sugar levels.
Blood sugar levels should go back to a healthy range once you have finished your course of steroids. Talk to your doctor about how to monitor your blood sugar levels if you have diabetes and are prescribed steroids. Strategies may include taking medicines, eating well and moving more.
Pancreatic cancer and diabetes
Some people with pancreatic cancer develop diabetes before the cancer is diagnosed or after surgery to remove the pancreas. The way diabetes is managed varies from person to person, but it usually includes making changes to your diet and taking medicines including insulin.
Malnutrition
When you eat foods with less energy and protein than your body needs over a period of time or you lose weight without trying, you may become malnourished. This can occur before, during or after treatment. Factors that increase the risk of malnutrition include:
- surgery for head and neck, lung and gastrointestinal cancers, which may make it hard to swallow and digest food
- increased nutritional needs caused by cancer and its treatments
- symptoms or side effects of treatment such as loss of appetite, nausea, vomiting, dry mouth and mouth sores
- loss of nutrients through diarrhoea or vomiting
- some medicines
- anxiety, stress and fatigue.
Difficulties with eating, swallowing and digestion can contribute to, or be symptoms of, malnutrition. Other signs include muscle weakness, significant weight loss, dry and brittle hair and nails, and pale or pigmented skin.
Malnutrition can increase your risk of infection and reduce your strength, ability to function and quality of life. It can also affect how your body responds to cancer treatment and make your recovery longer. It is possible to be malnourished even if you are overweight or obese. Talk to your doctor or dietitian for support.
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Eating with a stoma
After surgery for bowel cancer, you may need a stoma. This may be temporary or permanent. A stoma is a surgically created opening in the abdomen that allows bowel movements (faeces, stools or poo) to leave the body. The end of the bowel is brought out through the opening and stitched onto the skin. A bag is attached to collect the faeces.
If you have a stoma, you may need to change what you eat in the first few weeks to help the stoma settle. The amount of matter coming out of the stoma (output) will vary depending on how much and when you eat.
What to eat when you have a stoma
- Work with your dietitian to explore which foods cause problems for you. Different foods can affect people differently.
- Keep a diary of what you eat and how it affects you. Make a note of the foods that cause constipation or diarrhoea, gas, pain or bloating. It is better to limit – not eliminate – these foods in your diet, as you may find that what you can handle improves over time.
- When returning to your usual diet, introduce one food at a time. If something causes a problem, try it again in a few weeks to see if your response has improved.
- Share this information with your dietitian or the health care team because it can help them figure out how to manage any issues.
- Sometimes foods such as nuts, seeds and very fibrous foods can build up and block the stoma. A stoma blockage can be uncomfortable and cause a bloated feeling or nausea. If you experience symptoms of a blockage for more than two hours or you start vomiting, contact your nurse or hospital.
- If your stoma output is higher than recommended, drinking oral rehydration solutions can help replace the lost fluid. You can also ask your dietitian for information.
- The Australian Government’s Improving Bowel Function After Bowel Surgery booklet may be helpful.
- Visit the Continence Foundation of Australia for support.
Nutrition and advanced cancer
If cancer spreads from where it started to other areas of the body (secondary or metastatic cancer), problems with eating and drinking may occur or get worse. It’s common for people with advanced cancer to lose their appetite. This often leads to weight loss and malnutrition.
Controlling symptoms that affect your ability to eat or drink will help improve your quality of life. Soft foods and clear liquids may be easier to digest. It’s okay to focus on eating foods you enjoy.
Nausea and vomiting
Many people with advanced cancer have problems with ongoing nausea and vomiting. Nausea and vomiting may be caused by pain medicines, cancer growth, blockage in the bowel, slower digestion, or high calcium levels in the blood (hypercalcaemia). Feeling tired or anxious may make the nausea worse. Ask your doctor about what medicines may help.
Mouth problems
People with advanced cancer may have a dry mouth or a sore mouth and throat. These problems may be caused by drinking less or by some types of treatment. If chewing and swallowing become difficult, it may be necessary to change the texture of your food.
Blockage in the bowel
Cancer, surgery or changes to digestion in or near the abdomen sometimes cause the bowel to become blocked (bowel obstruction). This can also happen if the cancer comes back. Because faeces (stools or poo) cannot pass through the bowel easily, you may have symptoms such as nausea, vomiting, constipation or abdominal discomfort and pain.
To relieve symptoms of a bowel obstruction, you may be given medicines including laxatives and enemas, or have a small tube (stent) put in that helps keep the bowel open. The stent is inserted through the rectum using a flexible tube called an endoscope.
Cachexia
People with advanced solid tumours (e.g. cancer of the lung, pancreas, oesophagus, stomach, liver and bowel) may develop a muscle-wasting syndrome known as cachexia. This means the way the body uses protein, carbohydrates and fats changes, and it can burn up energy faster. Symptoms include:
- loss of weight, including loss of fat and muscle mass
- feeling sick (nausea)
- feeling full after eating small amounts
- anaemia (low numbers of red blood cells)
- weakness and fatigue
- inflammation in the body (shown on a blood test).
Your doctor or dietitian will discuss the best way to manage cachexia. They may suggest eating more foods high in energy, fat and protein, and taking nutritional supplements or medicines such as appetite stimulants.
If you continue to have problems maintaining your nutrition, your treatment team may recommend feeding through a tube in the nose or stomach. However, each person is different and depending on your situation, tube feeding may or may not be recommended. Your treatment team will give you more information.
Learn more from Peter MacCallum Cancer Centre.
Support from health professionals
Eating well and managing nutrition-related side effects can feel overwhelming, but there are many sources of support.
If you are referred to a dietitian, speech pathologist, exercise physiologist or physiotherapist as part of a Chronic Disease Management Plan, you may be eligible for a Medicare rebate for up to 5 visits per calendar year. Most private health insurers provide a rebate depending on the type and level of cover. Speak to your GP for more information.
Dietitian
An accredited practising dietitian (APD) is a health professional with a four-year university degree in science, nutrition and dietetics. Using scientific evidence, they modify diets to help treat disease symptoms and to get the most out of food without the use of supplements.
Dietitians work in all public and most private hospitals. You can ask your cancer care team if they can arrange an appointment with the dietitian. Dietitians in private practice may also have their own website.
Nutritionist
The term nutritionist refers to both qualified nutrition scientists and naturopathic nutritionists. Some dietitians call themselves nutritionists. Nutritionists working in the natural health industry should have at least a diploma of nutrition, or equivalent, from a university or naturopathic college. For nutrition advice specific to cancer or another disease or condition, speak to an accredited practising dietitian.
Speech pathologist
A speech pathologist is a health professional who diagnoses and treats people having difficulties with speech, language, fluency and voice. Speech pathologists also help people who have problems swallowing food and drinks. They need a university degree and may work in hospitals or in the community.
Exercise professionals
Physical activity is also important in managing your health and wellbeing. The most appropriate health professionals to design an exercise program for people with cancer are exercise physiologists and physiotherapists. Both have completed a four-year university degree.
They can help develop a program based on what you can do and any physical side effects related to the type of cancer you have.
Questions to ask your health professionals
Asking your doctor or dietitian questions will help you manage nutrition issues associated with your cancer treatment. You may want to include some of these questions in your own list:
Diet during treatment
- Will this cancer treatment affect what I can eat?
- Should I be on a special diet? Should I eat only organic foods?
- Should I avoid any particular food during treatment?
- What other changes to my diet can I expect?
- Is it safe to take vitamin supplements?
- I’d like to try a special diet I’ve heard might help. Is it likely to cause any harm?
- How can I stay strong during treatment?
- Should I see a dentist?
Symptoms and side effects
- Why am I losing/gaining weight?
- Why am I feeling sick?
- Why am I so tired?
- How can I reduce nausea? Will medicine help? When should I be taking anti-nausea medicine?
- What can I do about mouth ulcers? How long will they take to heal?
- Why has my sense of taste or smell changed? Will it return to normal?
- Will these symptoms go away and, if so, when?
- Are my bowel habits of concern?
- Can you refer me to a dietitian or speech pathologist for help with swallowing difficulties?
After treatment
- Do I need to change my diet after treatment ends?
- Is there a diet that can help me stay cancer-free?
- How can I get my strength and fitness back?
- Can you refer me to a dietitian to help with ongoing side effects?
Expert content reviewers:
Jacqueline Baker, Senior Oncology Dietitian, Chris O’Brien Lifehouse, NSW; Lauren Atkins, Advanced Accredited Practising Dietitian, OnCore Nutrition, VIC; Dr Tsien Fua, Head and Neck Radiation Oncology Specialist, Peter MacCallum Cancer Centre, VIC; Rosemerry Hodgkin, 13 11 20 Consultant, Cancer Council WA; Clare Hughes, Manager, Nutrition Unit, Cancer Council NSW; John Spurr, Consumer; Emma Vale, Senior Dietitian, GenesisCare, SA; David Wood, Consumer.
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The information on this webpage was adapted from Nutrition for People Living with Cancer - A guide for people with cancer, their families and friends (2022 edition). This webpage was last updated in July 2022.
