Cancer - About Cancer Blog!

Q: Are there any foods that should be avoided during chemotherapy? And if so, why? Are there any foods I should eat more of?

— Donna, Maryland

A: Chemotherapy can decrease your body's ability to fight infections. This is particularly true when the white blood cell count is low, since white blood cells are what your body mobilizes to fight off an infection with germs such as bacteria. Different types of chemotherapy affect your infection-fighting capabilities to different degrees and for different durations. For example, patients who undergo high-dose chemotherapy followed by stem cell transplantation have a profoundly decreased ability to fight off infections, and this vulnerable period can last for weeks. On the other hand, patients receiving outpatient, standard-dose chemotherapy for common cancers such as colon cancer and breast cancer may have low white blood cell counts for only a few days and carry a fairly small risk of developing an infection.
You may be instructed to avoid certain foods, such as raw fish, raw shellfish, unwashed fruit, raw milk, and raw egg products, while you're receiving chemotherapy. These precautions are encouraged to limit the possibility that uncooked or unwashed products will lead to an infection that will be harder to fight off because of chemotherapy. Washed fruit and vegetables are generally safe, as are meat and eggs that have been appropriately cooked and stored.

Other food-related precautions have less to do with infection risk and more to do with what might taste good and sit well in your stomach. Some patients find that spicy foods are more irritating while they are on chemotherapy. If your chemotherapy gives you mouth sores, then acidic foods (such as citrus and tomatoes) are likely to be irritating until the mouth sores heal. Finally, the body's ability to metabolize certain chemotherapy drugs — that is, its ability to process and clear the drugs from the system — may be affected by grapefruit juice, so you may be advised not to drink it near the time of your treatment days.

It is best to try to eat a balanced diet and to maintain a normal weight during chemotherapy. While it is sometimes thought that cancer patients are bound to lose weight, patients who are receiving adjuvant chemotherapy — chemotherapy given after a cancer has been completely removed in order to decrease the chance that it will come back — often gain weight. It is not clear yet why this happens. Some patients may purposely overeat for fear of losing weight, and others may eat frequently to keep nausea at bay. Also, many chemotherapy treatments involve the use of steroid medications, and these drugs can increase appetite.