Poor nutrition

All cells need nutrients to grow and work. Lack of vitamins, minerals, calories, and protein can weaken your immune system and make it less able to find and destroy germs. This means people who are poorly nourished (malnourished) are more likely to develop infections. People who are malnourished either do not take in enough calories and nutrients, or the body can’t use the food it takes in. Either way, it can weaken your immune system.

People with cancer often need extra calories and protein to support their immune system cells and other tissues. For example, recovery from surgery increases the body’s need for nutrients. People with cancer might be poorly nourished for many reasons:

• The cancer itself can make it hard to eat or digest food. This is common in people with cancers of the digestive system, mouth, or throat.
• Cancer treatments, like radiation therapy and chemotherapy, can cause nausea and a loss of appetite.
• Cancer cells use up nutrients, leaving less to meet the needs of normal, healthy tissues.

People with cancer often need help from dietitians or doctors to get enough calories and nutrients. Dietary supplements, tube feedings, or even intravenous (IV, through a vein) feedings may help in some cases.

Good nutrition and stress management may help improve the immune function of people with cancer, which may help prevent some infections. Your doctor might have you meet with a dietitian to plan what you should eat and for help managing eating problems. Nutrition counseling should include the importance of getting enough calories, protein, and vitamins. This is tailored to each person’s food intake and nutrition problems. Other therapies such as biofeedback, humor, music therapy, guided imagery, counseling, and meditation may help manage stress and make it easier to eat.