Poor nutrition can affect infection risk in people with cancer

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, stress management, and good self-care might help improve the immune function of people with cancer, which may help prevent some infections. It's important to know that avoiding or eating certain kinds of foods will not affect white blood cell counts (one reason your immune function may not be normal). However, your doctor might have you meet with a dietitian to plan what you should eat and to get 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.

Learn more about what to eat during cancer treatment in Nutrition for the Person With Cancer.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: February 16, 2015 Last Revised: February 25, 2015