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Other nutrition concerns

Some nutritional issues need extra care. Speak to your doctor or a dietitian for help managing these issues.

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 treatments such as chemotherapy, radiation therapy and surgery
  • 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.

Many of the difficulties with eating, swallowing and digestion can contribute to, or be symptoms of, malnutrition. Other signs of malnutrition include muscle weakness; significant weight loss; dry and brittle hair and nails; and pale or pigmented skin.

Having 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. You can become malnourished regardless of how much you weigh – it is possible to be malnourished even if you are overweight or obese. Talk to your doctor or dietitian if you think malnutrition may be an issue. It is important to do this early so you receive the right advice. They may ask you questions such as have you lost weight without trying or have you been eating poorly because of a decreased appetite.

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.

Enzyme replacement therapy

The pancreas produces digestive enzymes to help break down food. If you have had surgery for pancreatic cancer, your body may not be able to make enough of these enzymes. This will affect your ability to digest food and is often referred to as pancreatic exocrine insufficiency.

Signs include diarrhoea, pain in the abdomen, bloating and pale, floating faeces. To help prevent these symptoms, ask your doctor or a dietitian for information on enzyme supplements.

For more information, download our ‘Understanding Pancreatic Cancer’ booklet.

In some cases, 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 you eat 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.

For more information, download our ‘Understanding Bowel Cancer’ booklet. The Australian Government’s ‘Improving Bowel Function After Bowel Surgery’ booklet may also be helpful.

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Nutrition for People Living with Cancer

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This information is reviewed by

This information was last updated July 2022 by the following 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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