Ways to Keep Your Immune System Strong During Chemotherapy

While chemotherapy helps destroy cancer cells effectively, it can also damage and weaken some rapidly dividing normal cells, particularly the cells that make up the immune system.

A healthy eating pattern, exercise, and avoiding preventable illnesses are some ways that may help prevent these side effects.

Reducing stress, sleeping well, and avoiding alcohol and tobacco can also help protect the immune system.

A Nutritious, Balanced Diet

Balanced, nutritious eating during chemotherapy increases energy and may support the immune system.

However, chemotherapy and other cancer treatments can cause side effects affecting food intake. Chemotherapy can also change how the body processes and metabolizes nutrients.

Common nutrition-related side effects include:

• Changes in taste and smell
• Loss of appetite
• Nausea and vomiting
• Constipation
• Diarrhea

People receiving cancer treatment may need extra nutrients to maintain energy and cope with side effects. It is therefore important for them to be monitored at their treatment center by oncology dietitians.

The following suggestions may increase calorie and protein intake:

• Snack frequently throughout the day
• Choose foods you enjoy
• Eat every few hours rather than only when hungry
• Drink high-calorie, high-protein beverages, such as milkshakes and liquid supplements
• Drink between meals rather than during them to reduce fullness at mealtimes
• Do gentle exercise before meals to stimulate appetite
• If necessary, use appetite-stimulating medication prescribed by an oncologist

For a more detailed, carefully prepared individual nutrition plan, it is better to seek specialist help.

Exercise

When it comes to cancer treatment, exercise is at least as important as cancer medication.

Exercise is generally safe before, during, and after cancer treatment. Regular activity at every stage of the treatment journey may improve:

• Brain and body function
• Physical health, including:
• Bone health
• Muscle strength
• Range of motion
• Mental health
• Immune function
• Sleep
• Appetite
• Weight management
• Overall quality of life

Regular physical exercise may also relieve treatment side effects.

A 2022 study examined whether starting an exercise program during rather than after chemotherapy produced better long-term cardiorespiratory fitness. It included 266 cancer patients who completed a 12-week supervised program followed by 12 weeks of unsupervised exercise.

One group followed the program during chemotherapy and the other after completing it. Researchers assessed participants' health at various intervals throughout the study.

Compared with people who began exercising after chemotherapy, those who started during chemotherapy experienced:

• Less fatigue
• Less muscle loss
• Less overall loss of fitness

One year after completing the program, both groups:

• Reported similar fatigue levels
• Had regained their prechemotherapy muscle strength
• Reported better health-related quality of life than before starting chemotherapy

These findings suggest that:

• Exercising during chemotherapy offers greater health benefits than waiting until chemotherapy is complete.
• Exercise at any treatment stage may reduce chemotherapy side effects and support faster recovery.

Sleep

Sleep matters for both mental and physical health. A good night's sleep helps strengthen the immune system. Quality sleep also helps:

• Lower blood pressure
• Improve appetite
• Improve thinking ability

However, sleep problems are common among people receiving chemotherapy or other cancer treatments.

The following tips may help manage sleep problems and improve sleep quality during chemotherapy:

• Tell your doctor about cancer symptoms or treatment side effects interfering with sleep.
• Cognitive behavioral therapy (CBT) or relaxation therapy may be worth considering.
• Practice good sleep hygiene, which may include:
  • Going to bed only when tired
  • Keeping the bedroom dark, cool, and comfortable
  • Avoiding television or computer screens for a few hours before bedtime
  • Avoiding exercise for a few hours before bedtime
  • Avoiding a large meal before bed

Avoid Alcohol

A 2015 study found that alcohol disrupts immune-cell function and increases infection risk. It is also a major risk factor for certain cancers. The study states that even occasional heavy drinking weakens immune function.

Alcohol may interact with certain chemotherapy drugs and make a person feel unwell. It is therefore important to follow the prescribing specialist's advice about whether drinking alcohol is safe.

Avoid Smoking and Tobacco Products

Like alcohol, smoking can harm the immune system and impair its ability to fight infection and disease.

Many people continue smoking after a cancer diagnosis. However, this increases the risks of:

• Smoking-related second cancers
• Other chronic health problems
• Premature death

The World Health Organization (WHO) notes that tobacco smoke may affect how certain chemotherapy drugs are metabolized in the body, potentially leaving them less time to destroy cancer.

In particular, chemicals in tobacco smoke may cause certain chemotherapy drugs to be cleared from the body more quickly, giving them less time to destroy cancer.

The American Lung Association offers the following guidance for people wanting to quit smoking:

• Ask a specialist about medications or resources that may help.
• Tell family and friends you want to quit and ask for support.
• Join online or in-person support groups for people trying to quit.
• Contact a smoking-cessation helpline. In Turkey, you can call the Ministry of Health's Alo 171 line.

Reduce Stress

Chronic stress may disrupt a class of steroid hormones called glucocorticoids. These hormones may increase the risk of cancer cells becoming resistant to chemotherapy. They can also hinder the immune system's ability to recognize and destroy cancer cells.

Stress-management tips for people living with cancer and receiving treatment include:

• Be physically active regularly during and after cancer treatment.
• Ask a specialist for a referral to a mental health professional.
• Try a talking therapy such as cognitive behavioral therapy (CBT).
• Join online or in-person support groups for people living with cancer.

Preventing Infections

Chemotherapy can temporarily reduce the number of infection-fighting white blood cells (WBCs). This weakens the immune system and makes a person more susceptible to infection.

To avoid infections during chemotherapy:

Wash hands regularly: People receiving chemotherapy should wash their hands regularly and thoroughly to help reduce infection risk. Particular attention is needed:

• After blowing the nose, coughing, or sneezing
• After using the toilet
• After changing a diaper or helping a child use the toilet
• After touching a pet or cleaning up after it
• Before preparing food, during cooking, and after eating
• After touching garbage
• Before and after touching the area above or below an open wound

Practice good food hygiene: During chemotherapy, the risk of foodborne illness caused by bacteria, viruses, or parasites is particularly high.

• The following suggestions may help maintain food safety during chemotherapy and other cancer treatments:
• Refrigerate store-bought or prepared foods at 4°C or below within 2 hours of purchase or preparation.
• Keep raw meat in sealed containers away from ready-to-eat foods.
• Thaw meat, poultry, and fish in the refrigerator or microwave, not at room temperature.
• Use separate cutting boards for raw and cooked meat.
• Wash fruit and vegetables thoroughly under running water before peeling or preparing them, even if labeled “prewashed.”
• Wash the tops of canned foods before opening.
• Use different utensils to stir and taste food during cooking.
• Discard spoiled or moldy-smelling products.

Additional tips for avoiding illness:

• Wash hands after using public transport or visiting a public place
• Use alcohol-based hand sanitizer when soap and water are unavailable
• Avoid crowded places
• Wear a face mask in busy areas
• Stay away from anyone with a fever or infection
• Have an annual flu vaccination and encourage other household members to do the same
• Use moist antibacterial wipes to clean and disinfect surfaces at home or work
• Bathe daily and check for wounds needing treatment
• Avoid manicures and pedicures at beauty salons or spas
• Do not use hot tubs or outdoor swimming pools
• Do not share towels
• Do not share cutlery or drinking glasses

When the immune system is weakest during chemotherapy

• Of the various cancer treatments, chemotherapy weakens the immune system the most.
• Chemotherapy reduces white blood cell counts. Neutrophils are a type of white blood cell acting as the body's first line of defense, killing pathogens when signs of infection appear.
• Neutrophil levels begin falling approximately 1 week after the first chemotherapy cycle and start rising again before the next cycle (see What Are Leukopenia, Neutropenia, and Neutropenic Fever? Symptoms and Causes).
• People receiving chemotherapy have regular blood tests to assess immune-system function. Regular monitoring helps specialists evaluate how the immune system is working.

The Immune System During Chemotherapy: A Summary

Nutritious food, regular exercise, and good sleep are helpful ways to strengthen immunity during chemotherapy.

Other approaches include managing stress, limiting or avoiding alcohol, and quitting smoking. Protecting against bacteria and viruses also helps. Specialists can provide more personalized advice on supporting the immune system during chemotherapy.

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