Cancer And Malnutrition

Overview

Malnutrition is when your body doesn't get the right amount of calories, protein, vitamins, or minerals. In people with cancer, this can happen because the disease or its treatments change appetite, digestion, or how the body uses food. It is sometimes called cancer-related malnutrition.

Yes. Research shows that up to half of all people with cancer may develop malnutrition at some stage. It is more common in certain cancers like those of the stomach, bowel, or pancreas.

Anyone with cancer can be affected. However, it is more likely in people with cancers of the digestive system, people having intensive treatment, and those with advanced cancer. It can also affect children and older adults more seriously.

Symptoms

Common symptoms

• Unintentional weight loss
• Loss of appetite or feeling full quickly
• Tiredness and low energy
• Weakness in the arms and legs
• Changes in taste or smell
• Feeling cold or having dry skin

Symptoms in children

• Slower growth or weight gain
• Less playful or active than usual
• Tiredness and irritability
• Not wanting to eat foods they used to enjoy

Symptoms in older adults

• Sudden weight loss
• Muscle loss and weakness
• Difficulty with daily tasks
• Poor balance or falls
• Loss of interest in food

Causes

Main causes

• The cancer itself can change the body's metabolism and increase the amount of energy it uses.
• Cancer treatments such as chemotherapy, radiotherapy, or surgery can cause nausea, vomiting, mouth sores, or a sore throat.
• Pain, anxiety, or depression can reduce appetite.
• The cancer may move to parts of the digestive system and make it hard to eat or absorb nutrients.

Risk factors

• Cancer of the stomach, pancreas, bowel, or oesophagus
• Advanced disease
• High-dose chemotherapy or radiation to the head, neck, chest, or stomach
• Existing digestive conditions
• Being older or very young

When to see a doctor

See a doctor urgently if:

• You are losing weight quickly without trying
• You cannot eat or drink for more than a day
• You have severe nausea, vomiting, or diarrhoea
• You feel faint, confused, or too weak to move around

Book a routine appointment if:

• Your appetite has been poor for more than a week
• You have lost strength or are much more tired than usual
• You are concerned about your eating or weight

Diagnosis

Your doctor or nurse will ask about your weight, eating habits, and any symptoms that affect your appetite. They may use a simple questionnaire to check your nutrition risk, and they might do blood tests to look for low protein or vitamin levels.

Tests that may be done

• Weight and body mass index (BMI) measurement
• A nutrition screening questionnaire
• Blood tests (for example, for proteins, vitamins, and minerals)
• A physical examination to look for muscle or fat loss

What to expect at your appointment

If your team suspects malnutrition, you will be referred to a dietitian. The dietitian will talk with you about your normal meals, cultural preferences, and any difficulties you have. Together you will make a nutrition plan that fits into your life.

Treatment

The main approach is to get enough calories, protein, and fluids. Your team will also treat the causes of poor appetite or eating problems, such as nausea, pain, or mouth sores. A cancer dietitian can give you personalised advice.

Self-care at home

• Eat small meals and snacks every 2–3 hours.
• Add protein-rich foods like eggs, beans, fish, or full-fat dairy to your meals.
• Use adds like olive oil, butter, or cream to give meals extra calories.
• Drink between meals instead of before or during them.
• Try foods that are easy to eat, such as soups, smoothies, porridge, or moist stews.

Medical treatments

Some people may benefit from bottled nutritional drinks, which are available in supermarkets or pharmacies. Your doctor may also prescribe anti-nausea medicines, pain relief, or other treatments to help make eating more comfortable. Never start any medication or supplement without your doctor’s advice. If oral intake is not enough, your care team may consider a feeding tube or intravenous nutrition.

When is surgery considered?

Surgery is sometimes needed for the cancer itself, especially if a tumour blocks the digestive tract. It is not a first-line treatment for malnutrition, but it may be planned as part of your cancer care. Your team will explain if this is needed.

Living with this condition

Try to keep a pattern of eating, even if you don’t feel hungry. Keep easy snacks next to you, and let others help with cooking and shopping. Focus on small daily goals rather than being perfect.

Lifestyle tips

• Create a comfortable eating environment — a nice table, soft music, or company at mealtimes.
• Use ginger, mint, or lemon water for mild nausea.
• Ask about meal delivery services or frozen meals that are ready to heat.
• Set reminders to eat or drink every 1–2 hours during the day.

Diet and exercise

Gentle physical activity, such as short walks or light stretching, can help build your appetite and maintain muscle. Always check with your doctor before starting anything new. Your dietitian can suggest ways to balance activity and rest.

Mental health and emotional wellbeing

Dealing with cancer and eating problems can be stressful. You may feel anxious, sad, or frustrated. These feelings are understandable. Your care team can offer counselling or put you in touch with a mental health professional.

Prevention

Malnutrition is often preventable. Regular weight checks, early talks with a dietitian, and quick treatment of symptoms like nausea or pain all help. If you are starting cancer treatment, ask your team about your nutrition plan.

Screening programmes

Cancer care often includes regular nutrition screening. This means checking weight and asking questions about eating at each visit. If you notice a change, tell your team early so they can act quickly.

Complications

If left untreated

• Increased risk of infections
• More side effects from cancer treatment
• Muscle loss and weakness
• Slower recovery from surgery
• A lower quality of life

Long-term outlook

Nutrition support can be very helpful. Many people with cancer do well once they receive the right support for eating, symptoms, and emotional wellbeing. Even small improvements in nutrition can help you feel stronger and cope better with treatment.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.