Cancer And Food

Overview

This topic explains how food and nutrition are connected to cancer. It covers choosing foods that may help lower cancer risk, and eating well during and after cancer treatment.

Most people have questions about food and cancer. It is a common topic during doctor visits, and many people want to know which foods to eat or avoid.

Everyone can be affected by the link between diet and cancer. It is especially important for people who have been diagnosed with cancer, people who are undergoing treatment, and anyone who wants to reduce their cancer risk.

Symptoms

Common symptoms

• Unexplained weight loss
• Loss of appetite
• Nausea or vomiting after eating
• Feeling full after eating small amounts
• Changes in taste or smell of foods
• Difficulty chewing or swallowing

Symptoms in children

• Slower growth or poor weight gain
• Eating very little or refusing foods
• Nausea or stomach pain during eating

Symptoms in older adults

• Swallowing problems
• Weakness or fatigue
• Signs of dehydration, such as dark urine or dry mouth
• Weight loss without trying

Causes

Main causes

• Certain food components, like alcohol, processed meats, and highly processed foods, have been linked to a higher risk of some cancers.
• A diet low in fruits, vegetables, and whole grains may increase risk, but the exact reasons are not completely clear.
• Weight gain and obesity, which can be affected by food, are linked to several cancer types.
• How the body processes food, including insulin and blood sugar levels, may play a role in cancer risk.

Risk factors

• Living with obesity
• Drinking alcohol
• Eating a high amount of processed or red meat
• Eating few fruits and vegetables
• Having a family history of certain cancers

When to see a doctor

See a doctor urgently if:

• Unexplained weight loss
• Trouble swallowing
• Persistent vomiting or diarrhea
• Blood in your stool or vomit

Book a routine appointment if:

• If you have ongoing loss of appetite or difficulty eating
• If you are concerned about your diet and cancer risk
• If you are planning cancer treatment and want advice on nutrition

Diagnosis

There is no single test for 'cancer and food.' Instead, your doctor will ask about your eating habits, weight, and diet history. If cancer is suspected, they will do a physical exam and order appropriate tests. They may also refer you to a dietitian.

Tests that may be done

• Blood tests to check vitamin and mineral levels
• Height and weight measurement
• Body mass index (BMI) calculation
• Screening tests for certain cancers, such as colonoscopy or mammogram, based on your symptoms and risk

What to expect at your appointment

A dietitian or doctor will ask about what you typically eat, your appetite, and any weight changes. They may suggest keeping a food diary. If you have cancer, they will work with you to create an eating plan tailored to your needs.

Treatment

Treatment for cancer itself is managed by a cancer care team. For nutrition, the focus is on supporting your body with the right foods and addressing any eating problems caused by the cancer or its treatment.

Self-care at home

• Try to eat a variety of foods from all food groups, especially colorful fruits and vegetables, whole grains, and protein-rich foods like beans, fish, eggs, and poultry.
• If you have a poor appetite, try eating smaller meals more often and sipping fluids between meals.
• Choose soft, moist foods if mouth sores or swallowing difficulty are a problem.
• If your taste changes, try adding herbs, marinades, or citrus (unless mouth sores are present).

Medical treatments

Medical treatments for cancer may include surgery, chemotherapy (medicines to kill cancer cells), radiation therapy (using high-energy waves), or other targeted therapies. Alongside these, a doctor or registered dietitian may recommend nutritional support, such as special drinks or, in some cases, a feeding tube, if you cannot eat enough by mouth.

When is surgery considered?

For some cancers, surgery to remove a tumour may be part of the treatment. This is linked to food only in the sense that your nutrition needs can change before and after surgery. Your care team will guide you.

Living with this condition

Living with cancer and thinking about food can feel overwhelming. Focus on small, manageable steps: eat when you feel able, choose foods you enjoy, and accept help from family and friends with shopping or cooking.

Lifestyle tips

• Stay gently active, such as going for short walks, if you feel up to it and your doctor agrees.
• Get plenty of rest and allow yourself time to recover after treatments.
• Talk to a dietitian if you are unsure what to eat or drink.

Diet and exercise

Aim for a balanced plate: half fruits and vegetables, a quarter of whole grains, and a quarter of protein. If you are losing weight, you may need extra protein and calories. If you are gaining weight, your dietitian can help with portion sizes. Gentle exercise, such as walking, can help with appetite and energy levels, but always check with your care team.

Mental health and emotional wellbeing

A cancer diagnosis and changes in eating can cause stress, anxiety, and sadness. It is normal to feel this way. If you are struggling, please talk to your care team. Many people find support from friends, family, or a counsellor. If you have thoughts of self-harm or feel unsafe, tell someone you trust or contact your local emergency or crisis service immediately.

Prevention

There is no guaranteed way to prevent cancer. However, eating a healthy, balanced diet, staying physically active, and keeping a healthy weight are all linked to a lower risk of many cancer types.

Vaccines

Some vaccines help prevent cancers caused by infections, such as hepatitis B and HPV. Ask your doctor if these are right for you.

Screening programmes

Screening tests, such as bowel cancer screening or cervical screening, can find cancer early or detect changes before cancer develops. Talk to your doctor about which screenings you need and when.

Complications

If left untreated

• If cancer is left untreated, the disease itself can spread and become harder to treat.
• Poor nutrition can worsen weakness and weight loss and make treatment harder to tolerate.

Long-term outlook

Many people with cancer live full and active lives. A good diet will not cure cancer on its own, but it can help you feel better, keep your strength, and support your treatment. Every person’s situation is different, so talk to your care team about what is right for you.

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