Managing nutrition-related side effects of cancer treatment

There are a number of common side effects associated with cancer treatment, but there are also ways to manage these and minimize their severity


Fatigue is a common side effect of cancer. Fatigue can be caused by the cancer itself, radiation therapy or chemotherapy, not eating, low blood counts, poor sleep or depression. While fatigue is not a nutrition problem, it can affect the way that you eat. You may become too tired to eat or prepare foods. It is important to let your doctor know if you are experiencing fatigue.

The following tips may help:

  • Make sure you are getting enough rest. Take several naps or rest during the day
  • Take short walks or do some light exercise if possible
  • Ask your friends and family for help grocery shopping and preparing foods
  • Cook in large quantities and freeze meals in advance
  • Keep easy to prepare meals and snacks handy
  • Try to eat smaller meals more often throughout the day
  • Choose foods that are high in protein and calories to get the most nutrition in every bite. Be creative—add calories and protein to the foods you eat
  • Consider a nutritional shake
  • Make sure to drink enough fluids—dehydration can make you feel tired
  • Talk to your doctor or nurse about your fatigue
  • If you have anemia, make sure to take the medications and/or supplements recommended by your healthcare team


Problems with constipation are common. Stress, lack of exercise, certain medications (especially pain medication), and inadequate fluid or fiber intake may all be contributing factors to constipation.

The following tips may help:

  • Drink plenty of fluids. Try prune juice or a hot beverage to help promote bowel movement. Drink liquids with meals and between meals to keep your intake as high as possible
  • Slowly increase fiber in your diet
  • Introduce yogurt with active cultures
  • If gas is a problem, limit foods and drinks that cause gas such as onions, beans and carbonated beverages
  • Take walks and exercise regularly but check with your physician before making any drastic changes in your exercise routine. Try to get as much light exercise as your condition will allow
  • Talk to your doctor about appropriate medical management including the use of stool softeners or laxatives


Diarrhea has many causes including chemotherapy, radiation therapy to the pelvis, stomach and abdomen, infections and food sensitivities.

The following guidelines may help you control these symptoms and keep you as comfortable as possible. Be sure to tell your doctor or nurse if you are experiencing loose or watery stools.

  • Drink fluids to replace what is lost through diarrhea. Drink even if you are not thirsty. Try water, diluted juice, gelatin and sports drinks with electrolytes.
  • Eat small amounts of food and drink small amounts of liquid throughout the day rather than three large meals
  • Drink and eat foods high in sodium and potassium. Sodium and potassium are important minerals that are lost when you have diarrhea. Some foods high in potassium include bananas, honeydew, sweet potatoes, avocado, apricot and cantaloupe. Foods high in sodium are broth, soups, sports drinks, crackers and pretzels. If you have kidney disease, be sure to consult with your doctor before increasing the sodium and potassium in your diet
  • Try Rice Congee: Take one cup of long-cooking rice and combine with six to seven cups of water and one tablespoon salt. Cook this according to package directions, typically about 40 minutes. This will be a sticky, soupy mixture
  • With your doctor’s permission, consider the use of a bulking agent containing psyllium fiber, such as Metamucil
  • Avoid foods that are high in fiber including raw fruits and vegetables, whole-grain breads and cereals and beans
  • Avoid foods high in fat as they may also contribute to diarrhea or loose stools
  • Avoid spicy foods
  • Avoid alcoholic beverages
  • Avoid milk and milk products if they are irritating to you. They can lead to diarrhea, gas or cramps due to temporary lactose intolerance. Try lactose-free dairy products instead
  • Avoid foods that may cause gas, such as beans, cabbage, broccoli, corn, cauliflower and spicy foods, if you are experiencing stomach cramps. You may take anti-gas medications—ask your healthcare provider

The low-fiber diet, which is also called a low-residue diet, is designed to reduce the number of bowel movements and is typically used for people experiencing diarrhea or abdominal cramping. You should choose foods low in fiber until your symptoms resolve, then slowly begin adding fiber into your diet. Use soluble fiber foods such as oatmeal, applesauce and bananas.

General diet guidelines

  • No fatty, greasy or fried foods
  • Avoid dairy products if they are irritating to you
  • Eat cooked fruits and vegetables (not raw)
  • Choose white or refined breads and cereals

Decreased appetite and taste changes

Decreased appetite is one of the most common side effects of cancer treatment. A poor appetite can be caused by the cancer itself or other side effects of treatment such as nausea and vomiting and taste changes.

Changes in taste can make food less enjoyable. Foods can start to have a bitter, metallic or even salty taste.

It is important to continue to eat well even when you do not feel a strong desire to eat. Think of food as one of the medications you must take every day.

Try these tips to help manage your symptoms:

  • Eat smaller meals more often throughout the day instead of three large meals
  • Ask your dietitian or doctor about liquid nutritional supplements or “instant breakfast” drinks
  • Keep nutritious snacks available so you can eat whenever you get the urge (nuts, muffins, peanut butter, yogurt, pudding, hardboiled eggs, milk, etc.)
  • Liquids can also provide calories and important nutrients when you do not feel like solid food. Try juices, soups or milkshakes
  • Add calories and protein to foods you can tolerate
  • Ask your doctor about medications that can help increase your appetite

Nutrition tips for taste changes:

  • Try using different marinades with your meat—honey, sweet and sour sauce, fruit juice, Italian dressing, sweet wine
  • Eat cold or room temperature foods
  • Season your food with lemons, vinegar, or try pickled foods. Be careful if mouth sores are present
  • Be sure to practice proper mouth care
  • Use a solution to cleanse your taste buds. Mix one teaspoon salt and one teaspoon baking soda into one quart of water. Rinse the mouth with this homemade mouthwash to clean the palate frequently throughout the day
  • If foods taste bitter or metallic: use plastic silverware, flavor foods with herbs (such as oregano, basil, onion or garlic), or use sauces like ketchup, mustard and barbeque sauce to enhance flavor

Nausea / vomiting

Preventing nausea and vomiting is key. Be sure to take your antiemetic medication exactly as prescribed by your treating physician. You should eat when you feel best. Do not force yourself to eat when nauseous. Try to eat six to eight small meals throughout the day instead of three large meals.

Try the following foods that are easy to digest:

  • Clear liquids, such as broth, tea, fruit punch, gelatin, Popsicles, sports drinks, clear sodas, water or ice chips
  • Gelatin
  • Toast or crackers
  • English muffins or bagels
  • Angel food cake
  • Rice
  • Vanilla wafers
  • Noodles
  • Potatoes
  • Eggs
  • Baked or grilled chicken
  • Canned or fresh fruit

Other tips:

  • Eat and drink slowly. Try drinks and foods at room temperature or cooler as hot foods may add to your nausea.
  • Sip most of your fluids between meals. Try using a straw or covered mug.
  • Rest after eating, but don’t lie down until an hour after your meal
  • Avoid wearing tight-fitting clothes
  • Contact your doctor if unable to keep food down

Sore mouth and throat

If your mouth and throat become sore during cancer treatment, healing will occur more rapidly if you drink plenty of fluids and continue to eat well. Choose foods that are soft, creamy and wet.

Mouth sores

Cancer treatment can lead to mouth sores. It is important to use proper mouth care and clean your teeth and gums. Use these tips to keep your mouth healthy.

  • Use a mouth rinse after each meal and at bedtime to keep bacteria from growing. You can use more often if desired. To make this, mix one teaspoon salt and one teaspoon baking soda into one quart of water
  • Increase your intake of fluids
  • Consume foods high in protein such as nutritional shakes, beans, yogurt, eggs, milk, cheese, peanut butter and poultry
  • Clean teeth and gums thoroughly with a soft toothbrush after meals
  • If you wear dentures, clean them daily and remove them whenever possible. Loose-fitting dentures, in particular, can irritate the mouth and gums
  • Ask your healthcare provider about over the counter mouth care choices
  • Let your doctor know if you notice white patches on your tongue or other areas of your mouth as this may be a sign of thrush

What to avoid:

  • Foods that are hard or crunch, spicy or acidic
  • Commercial mouthwashes that contain alcohol

Smoking or chewing tobacco

Dry mouth / thick saliva

Cancer treatment can cause a dry mouth and a decrease of saliva. The existing saliva may become very thick, sticky and stringy. Saliva is important not only for moisturizing the mouth, but for keeping your teeth and gums healthy.

This is usually a temporary problem, although in some cases it is permanent. There is no single way to treat dry mouth. However, there are guidelines you can follow:

  • Choose smooth, soft, creamy foods like macaroni and cheese, mashed potatoes, puddings and custards
  • Take frequent sips of fluid throughout the day
  • Limit sugar due to the increased risk of dental problems
  • Pause often while speaking to sip liquid
  • Rinse your mouth with a baking soda and salt solution before and after meals
  • Use nectars, low acid fruit juices or fresh or canned fruit
  • Suck on fruit juice Popsicles, ice chips or other cold foods
  • Try dipping or soaking food in whatever liquid you are drinking
  • Use viscous Lidocaine or other analgesic before meals

What to avoid:

  • Alcohol and tobacco
  • Commercial mouthwashes that contain alcohol
  • Hard, crunchy foods
  • Highly sugared drinks
  • Salty, spicy or acidic foods that irritate your mouth


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