Malnutrition and Cancer

What is malnutrition?
Malnutrition in people with cancer occurs when you are eating less energy and protein than the amount your body needs. This can lead to unplanned weight loss and a reduction in body fat and muscle. Compared to the rest of the population, people with cancer are at a higher risk of malnutrition. It is important to prevent malnutrition or identify it early, as malnutrition can affect how your body responds to your cancer treatment and your recovery.

Why are cancer patients at risk of malnutrition?
Many factors can increase the risk of malnutrition when you have cancer, including:
  • The cancer itself and the part of the body involved. If the cancer involves the head and neck or gastrointestinal areas (including stomach and bowel) it may be more difficult to swallow and digest food
  • Cancer treatments such as chemotherapy, radiotherapy and surgery can increase your energy and protein needs
  • Side effects from cancer treatment may make it more difficult to eat
  • Being unwell in hospital
  • Stress and anxiety
  • Fatigue and loss of energy

How do you know if you are malnourished?
Sometimes it is difficult to know if you are malnourished and changes in food intake and activity can be mistaken for other factors. Some signs to look out for include:
  • Eating less than usual, feeling full quickly or not eating between meals.
  • Even a small drop in your weight (3 or 4 kg) without trying can put you at risk of being malnourished. It is possible to be malnourished even if you are overweight.
  • Reduced physical performance, such as not being able to walk as fast or far as usual.
The diagram below shows some factors that contribute to malnutrition. These can also be signs that you have or are at risk of malnutrition.

Why is malnutrition a problem in cancer patients?
Malnutrition can lead to a reduced response to cancer treatments, increased side effects and possibly reduced survival. It can increase your risk of infection and the time you spend in hospital. Malnutrition can also reduce your strength and quality of life.  

Even if you are overweight, losing weight during your cancer treatment and recovery can increase your risk of malnutrition. Eating well is therefore very important for your health before, during and after cancer treatments.

How can malnutrition be prevented or managed?
Malnutrition and weight loss can usually be prevented. It should not be considered an expected side effect from cancer or treatments. Your doctor or nurse will regularly ask you questions about your weight and appetite to check your risk of malnutrition. A dietitian can determine whether you have malnutrition. They can work with you to ensure you are following an appropriate and balanced diet, and aim to avoid or minimise weight loss. Your dietitian may suggest some dietary changes and provide you with information on:
  • A diet high in energy (calories) and protein
  • Nourishing drinks including milk drinks
  • Smaller and more frequent meals
  • Different food that may be easier to chew or swallow
  • Nutritional supplement drinks
There are no special diets or food to include or avoid when you have cancer. It is important to ensure you include food from all food groups. Your dietitian may suggest less focus on including lots of fruits and vegetables and recommend eating more snack food, desserts, full cream dairy food and eggs. These food can help you meet your energy and protein needs. This may be quite different to your normal eating patterns.

In some situations, it is not possible to meet your nutritional needs through eating alone. Your dietitian and doctor may recommend the use of a feeding tube or intravenous nutrition to help.

It is important to let your doctor, dietitian or pharmacist know if you are taking any nutrition, vitamin or herbal supplements as they can sometimes interact with cancer treatments and medications.

Further information
A dietitian can provide you with further information and advice on preventing or managing malnutrition. A referral can be made through your doctor or health service. 

Besides that, the Malaysian Dietitians’ Association can direct you to a dietitian in your local area.

Malaysian Dietitians’ Association (MDA)
Website: www.dietitians.org.my
Reviewed by:
Jenelle Loeliger, Head - Nutrition Department, Peter MacCallum Cancer Centre; Kathryn Marshall, Senior Project Dietitian, Peter MacCallum Cancer Centre; Lauren Muir, Clinical Dietitian, Peter MacCallum Cancer Centre Reviewed by Chan Wan Thung, dietitian, NCSM.