Cancer and malnutrition

Malnutrition occurs when a person doesn’t get enough food or the right type of food, or has problems absorbing it. A common type of malnutrition in people with cancer is under-nutrition. This is when the body takes in less energy or fewer essential nutrients (such as protein and vitamins) than it needs. Under-nutrition causes the body to break down fat and muscle, leading to unplanned weight loss.

People with cancer are at higher risk of malnutrition than the rest of the population. A 2014 study found that approximately one in three people undergoing cancer treatment (of all types) had malnutrition.

If you have cancer, malnutrition can affect how well your treatment works, as well as your strength, recovery and quality of life. It can increase the time you spend in hospital and the risk of infection, and it has the potential to shorten life span.

Causes of malnutrition in cancer#

For some people with cancer, it can be difficult to eat enough of the right kinds of food. This may happen for many reasons, including:

• The type of cancer and the part of the body affected. Cancer in the head, neck or gastrointestinal system can affect your ability to swallow or digest food.
• The type of treatment. Surgery, chemotherapy and radiotherapy can increase your body’s energy and protein needs.
• Side effects from treatment. Nausea, vomiting and diarrhea can make it hard to eat, and the food you do eat might not be absorbed as well as usual.
• A hospital stay. Being unwell in hospital can affect your appetite and your ability to take in food.
• Anxiety or depression. Living with a cancer diagnosis is understandably stressful and can affect how much you eat.

While many factors can lead to weight loss during cancer treatment, weight loss should not be seen as an expected outcome. There are things you can do to support good nutrition and maintain your weight, and it is important to eat well before, during and after treatment.

Symptoms of malnutrition in cancer#

Several physical symptoms might suggest that you are malnourished or at increased risk. People with cancer and their carers can look out for:

• poor appetite, eating less than usual or not eating between meals
• unplanned weight loss, where even a small amount (three to four kg) can be a concern
• feeling full quickly
• pain or dryness in the mouth or throat
• difficulty chewing or swallowing food
• changes to your sense of smell and taste, which can affect your food choices
• diarrhea or constipation, which can affect how well nutrients are absorbed
• nausea and vomiting, which can affect your ability to eat and absorb nutrients
• fatigue, such as not being able to walk as far or as fast as usual

People undergoing cancer treatment should aim, at the very least, to maintain their weight. It is important to remember that malnutrition can occur even if you are overweight.

Identifying and diagnosing malnutrition#

Early identification of malnutrition risk is important. This may involve a screening tool that checks for unintentional weight loss or reduced appetite. Where appropriate, you can be referred to a dietitian, who can diagnose whether you are malnourished.

A full assessment of your nutritional status should be completed by a dietitian and may include:

• taking a medical history
• asking about recent changes to your appetite, weight, energy levels and eating patterns
• an assessment of your food and drink intake
• a physical assessment of muscle and fat stores
• ordering blood tests

The dietitian can then assess you regularly and develop an eating plan to help maintain your weight and nutritional status.

Treatment of malnutrition in cancer#

Your dietitian may suggest dietary changes that are different from your usual eating patterns to avoid or minimise weight loss and support your recovery. These might include:

• increasing your energy (kilojoule or calorie) and protein intake
• consuming nourishing drinks, including milk drinks that contain high levels of protein
• eating smaller meals more frequently
• choosing foods that are easier to chew or swallow
• eating more snack foods, desserts and full-cream dairy foods
• taking nutritional supplement drinks

People with cancer generally do not need to eat or avoid any particular foods, and it is important to include foods from all food groups. However, your dietitian may suggest putting less focus on filling foods such as fruits and vegetables, and more on energy- and protein-rich foods, which can help you meet your needs. This may be quite different from your normal eating patterns.

Let your doctor, nurse, dietitian or pharmacist know if you are taking any nutritional, herbal or vitamin supplements, as some can interfere with the effectiveness of your cancer treatment and medication.

Feeding tube or intravenous nutrition#

In some situations, a feeding tube might be needed temporarily to help reduce your risk of becoming malnourished. This can be a soft tube passed down your nose and throat into your stomach, or a longer-term tube inserted directly through your stomach wall. Specialised liquid nutrition is then fed directly into your stomach.

You might need a feeding tube in situations such as:

• significant ongoing weight loss
• head or neck cancer
• esophageal cancer
• lung cancer
• a very dry or painful mouth
• difficulty swallowing

Less commonly, your doctor might recommend that nutrition is given through a line inserted directly into a vein (intravenous or parenteral nutrition). In this case, you don’t have to eat, because the nutrients are supplied directly to your bloodstream to help maintain your body weight.

Key points#

• A common type of malnutrition in people with cancer is under-nutrition.
• A 2014 study found that approximately one in three people undergoing cancer treatment had malnutrition.
• Malnutrition can increase the time you spend in hospital and the risk of infection.
• It is important for people with cancer to eat well before, during and after treatment.
• A number of physical symptoms can indicate that you are malnourished or at increased risk.

Where to get help#