Dealing With Treatment Side Effects


Fatigue is the most common side effect in those undergoing cancer treatment. For some, fatigue may continue after treatment ends. It can significantly affect your quality of life and make it difficult to prepare and eat nourishing meals.

  • Temporarily rely on convenience products, like ready-to-eat foods, frozen dinners, frozen or canned fruits and vegetables, prepared pasta sauces and instant rice. Check labels for healthy choices – low in sodium and high in protein and fiber.
  • Keep healthy snacks on hand. Examples are dried fruits, cheese on whole-grain crackers and graham crackers.
  • Prepare food when you’re feeling best. Prepare large quantities of your favorite meals and freeze leftovers in meal-size portions. Make blended fruit and yogurt shakes that can be kept in the refrigerator.
  • Get help with meals from friends and family members. Phone for restaurant delivery or carry-out or have meals delivered by a service such as Meals on Wheels.
  • Try to get regular physical activity. Strong, consistent evidence shows that regular activity can relieve fatigue and also enhance mood and appetite.

There are many different causes of fatigue, including depression and difficulty sleeping. Talk to your doctor about your fatigue, and any other related symptoms, to determine if you’d benefit from treatments.

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Loss of Appetite, Weight Loss and Undernutrition

Weight loss and undernutrition are common among cancer patients due to loss of appetite and other factors that affect eating. When severe, these issues can lower your quality of life and interfere with the functioning of important body organs such as the heart, liver and kidneys. It can also slow your body’s ability to heal from surgery or radiation-induced tissue burns and infection.

  • Eat several small meals a day instead of three large meals.
  • Eat high-protein foods first in your meal while your appetite is strongest – foods such as beans, chicken, fish, meat, yogurt and eggs.
  • Eat your largest meal when you feel hungriest, whether that’s at breakfast, lunch or dinner.
  • Keep food interesting, whether by changing up recipes and seasonings or eating at a nice restaurant.
  • Keep favorite foods and high-calorie foods and beverages around the house or your environment during the day.

If you cannot take in enough nutrition through food, ask your health practitioner about blenderized drinks like milkshakes and smoothies, liquid or powdered commercial nutritional supplements (which are easy to swallow and digest), or the possibility of tube feeding. If it becomes too difficult for you to get nutrients through food – when the gastrointestinal tract is not working effectively, for example – total parenteral nutrition (TPN) may be appropriate to consider. TPN involves providing nutrients directly into a vein. TPN is costly and may have side effects, however, so your doctor will want to explore all other options first, including possibly feeding through a tube.

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Weight Gain

Weight gain is commonly seen during treatment of breast and certain other cancers, in women undergoing hormonal therapies, or as a result of “induced/early menopause” from chemotherapy. While the exact causes are not known, weight gain may result in part from a change in diet and exercise routines, such as eating more due to stress or to control nausea, and being less active due to fatigue. If steroids are part of your cancer treatment, they can be powerful appetite stimulants.

You may also be gaining weight because of fluid retention; if you are, see below. Tell your doctor about excess weight, especially if you gain weight rapidly over just a few days, so the cause can be identified.

  • Concentrate on healthy foods such as vegetables, fruits, whole grains and beans and other foods that are naturally low in calories and high in fiber to help you feel full.
  • Pay attention to portion sizes, checking food labels and the serving sizes listed.
  • Love what you eat. Include and savor foods that you enjoy most so you feel satisfied.
  • Eat only when you’re hungry. Consider psychological counseling or medications if you find yourself eating to address feelings of stress, fear or depression, and try to find alternatives to eating out of boredom.
  • Try to get regular physical activity, which can help manage your weight and relieve your fatigue.

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Fluid Retention

When patients gain weight during treatment without eating extra calories, the weight increase may be due to edema, or swelling. Certain common drugs such as prednisone and gabapentin can cause the body to retain too much fluid, as can a nutritional deficiency. Tell your health practitioner about rapid weight gain so he or she can determine the cause.

  • Drink plenty of water unless you have been specifically advised by your doctor to limit fluids.
  • Eat less salt and foods with less sodium such as fresh or frozen fruits and vegetables and unsalted or reduced-sodium snacks and soups. Replace processed foods such as cold cuts, which can be high in sodium, with alternatives.
  • Stay as physically active as possible.
  • Elevate your legs when resting.
  • If needed, your physician can prescribe medications to minimize fluid retention.

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Nausea is a common side effect of cancer treatment. It can sometimes be accompanied by vomiting. Anticipation of a treatment session can cause nausea in some cases.

  • Eat small amounts of food often and slowly, instead of large meals. If nausea in the morning is a problem, keep crackers and soda at your bedside to nibble on before getting up.
  • Eat foods at room temperature or cooler, as hot food can aggravate nausea because of strong odors.
  • Eat sitting up, and rest sitting up or reclined with your head raised for about an hour after eating.
  • Drink beverages between meals instead of with a meal. Drink beverages cool or chilled and sip through a straw.
  • Rinse out your mouth before and after eating, and suck on a hard candy such as peppermint or lemon if you have a bad taste in your mouth.
  • Avoid triggers where possible by recognizing times, foods, smells or events that trigger your nausea and trying to change your schedule or diet to avoid them.
  • If the smell of food or cooking nauseates you, try to keep the room well-ventilated; prepare meals that don’t require cooking; ask others to cook your meals for you or have meals delivered from Meals on Wheels or other similar services.
  • For nausea from radiation therapy or chemotherapy, eat bland, soft foods on treatment days and avoid eating for an hour or two before treatment. If you find that the anticipation of treatment causes nausea, practice relaxation or meditation techniques or another activity to distract yourself.
  • Discuss the use of anti-nausea medications with your doctor.

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Vomiting can follow nausea and can be brought on by some cancer treatments. Other factors can make vomiting worse such as food odors, gas in the stomach, or motion. Vomiting may occur without associated nausea. Tell your doctor if you have persistent vomiting and cannot keep liquids down. It is important to prevent dehydration if you are vomiting.

  • Sit upright and bend forward after vomiting.
  • Don’t eat or drink until your vomiting is controlled.
  • Once vomiting is under control, try drinking small amounts of clear liquids.
    Examples: cranberry juice, cool broth or flat soda (carbonated beverages can lead to vomiting in some people).
  • Try eating small amounts of soft foods such as cream of wheat, pudding, frozen yogurt or gelatin when you are able to keep down clear liquids. And gradually work your way back to your regular diet.

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Diarrhea is another possible side effect of cancer treatments, including chemotherapy and other medications, radiation therapy to the abdomen, and surgery. Other potential causes include infection, food sensitivity and emotional upset. Call your health practitioner if you have severe or long-term diarrhea, which may cause dehydration, nutrient loss and other health problems. Medications may be helpful.

  • Drink plenty of liquids, aiming for at least eight 8-ounce glasses each day. Good choices of fluids include water, diluted juice, broth or decaffeinated coffee or tea. Liquids at room temperature may be easiest to tolerate.
  • Eat small amounts of food throughout the day rather than three large meals.
  • Some doctors recommend temporarily following a “BRAT” plan – a low-fiber regimen featuring bananas, rice, apple sauce and toast – but its effectiveness is currently being reexamined. Check with your doctor.

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Constipation can result from some cancer treatments and pain medications. Constipation can also happen if you are not eating enough fiber or drinking enough fluids. Relying on tube feedings or physical inactivity for extended periods of time can also cause constipation.

  • Drink more liquids, aiming for at least eight 8-ounce glasses a day. Liquids can help keep stools soft. Good choices include water, prune juice, warm juices, decaffeinated teas and hot lemonade.
  • If you develop gas, limit certain foods. Culprit foods include broccoli, cabbage, cauliflower, beans, cucumbers, onions and carbonated drinks. Over-the-counter anti-gas products with simethicone may help you avoid discomfort from these foods. Always check with your doctor before self-medicating, even with over-the-counter medications.
  • Eat a large breakfast, including a hot drink and high-fiber foods (like hot or cold cereal, whole-wheat toast and fruit).
  • Increase your physical activity, aiming for a walk or other limited exercise every day.
  • Consider a fiber supplement or over-the-counter medications such as stool softeners or laxatives if necessary. Always speak with your health practitioner first for specific guidance. (Remember to drink plenty of fluids with such a supplement.)

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Feeling Full Quickly

Feeling full from a small amount of food can occur for a variety of reasons and is especially likely if you’ve had upper abdominal surgery. It is important to try to eat enough to allow you to strengthen your body and support healing. Your doctor may prescribe a medication to help.

  • Eat small meals throughout the day, keeping healthy between-meal snacks on hand.
  • Fortify your meals with calorie-rich, nutritious foods.
  • Avoid fried or greasy foods because fat lingers in your stomach longer than carbohydrates or protein. Avoid foods that give you gas.
  • Drink beverages between meals rather than during meals, so you feel less full while eating.
  • Rest after meals with your head elevated.
  • Ask a health professional about drinking blenderized drinks (milkshakes, smoothies), liquid or powdered commercial meal replacement beverages to boost calories and nutrients.

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Taste Changes

Changes in how foods taste can result from chemotherapy, radiation therapy or the cancer itself. Some people experience bitter or metallic tastes, especially when eating high-protein foods such as meat. Each person’s sense of taste can be affected differently, though, and so the best approaches for minimizing the unpleasant taste or enhancing flavor can vary, too. It may simply take some time after treatment is completed for your sense of taste to return to normal.

  • Choose foods that appeal to you. Moist and naturally sweet foods such as frozen melon balls, grapes or orange wedges may be particularly appealing, as may tart foods and beverages such as oranges, lemon yogurt or lemonade (but not if your mouth is sore).
  • If the taste of red meat is now less appealing, find healthy alternatives, such as chicken, turkey, fish, beans, nut butters, eggs or dairy products.
  • Marinate meats in juice, teriyaki sauce, barbecue sauce, Italian dressing or other flavorful liquid you find appetizing.
  • Add small amounts of sugar to some foods, which may decrease salty, bitter or unpleasant tastes.
  • Serve foods cold or at room temperature, which may improve how they taste.
  • Brush your teeth and tongue and rinse your mouth regularly, especially before eating, to clean your tastebuds. Choose alcohol-free mouthwashes; look at the label for inactive ingredients.
  • Rinse your mouth several times a day with water or a baking soda mixture (one quart water combined with one tablespoon of baking soda).
  • Try sour candies.

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Milk or Lactose Intolerance

People who digested milk and milk products easily before radiation or chemotherapy treatment may find they experience an intolerance to these products resulting in cramps and diarrhea. This is not common; however, and for most small amounts of dairy foods can still be tolerated in people who otherwise regularly eat them.

  • Try small portions of milk, yogurt or cheese to see if you can tolerate them. Yogurts and aged cheeses may be easier to tolerate than other dairy products.
  • Avoid only the milk products that give you problems.
  • Consider trying reduced-lactose milk or milk that contains an enzyme product to help in its digestion. Such enzyme products are also available in pharmacies in capsule, pill or liquid drop form.
  • Try calcium-fortified non-dairy drinks and foods, which you can identify by food labels. And speak with your health practitioner or registered dietitian about whether a calcium supplement could be beneficial. NOTE: These supplements can cause bloating and constipation.
  • Eat more calcium-rich vegetables, including broccoli and greens. If eating broccoli gives you gas, try other calcium-rich vegetables like kale, spinach, arugula and collard greens.

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Food Aversion

Cancer patients often associate a particular food with the onset of unpleasant symptoms. This phenomenon is called “acquired food aversion.”

  • Avoid eating your favorite foods when you know you are likely to feel sick. That way you will enjoy your favorites during times you’re feeling well.
  • Remember that your food aversion will pass. In the meantime, focus on eating healthy foods you do like.

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Sore Mouth, Tongue and Throat

Soreness in the mouth or throat can result from cancer treatment or for other reasons. See your health practitioner to ensure that the soreness is not due to an infection. If it is a side effect of cancer treatment it will generally clear up in time.

Also, see your dentist before beginning cancer treatment or between treatments to help prevent dental problems.

  • Prepare easy-to-swallow foods and include high-calorie and high-protein foods if you are having difficulty maintaining your weight. Cook foods until they are soft and tender and cut them into small pieces, or choose foods you can mash, blenderize or purée.
  • Serve foods cool or at room temperature, which can be less irritating than foods that are either hot or cold. For some, cold foods such as sherbet or popsicles may also soothe soreness.
  • Drink through a straw.
  • Avoid alcohol, which can irritate the cells lining your mouth.
  • Rinse your mouth several times a day with water or a baking soda mixture. Avoid commercial mouthwashes, which often contain alcohol, instead opting for an alcohol-free mouthwash.
  • Consider a medication to alleviate pain before meals or a product to numb your mouth and throat while you eat. Your doctor can prescribe a medication, special mouthwashes, anesthetic lozenges or sprays.
  • Use a soft toothbrush. Or, if your gums are sensitive, clean your teeth with cotton swabs or mouth swabs made especially for this purpose.
  • Remove your dentures if your gums are sore, except while eating, and keep your dentures clean.
  • Don’t smoke.
  • Tell your doctor immediately if your gums bleed during treatment, or if you see small white patches in your mouth. This will require a visit with your dentist or a periodontist and may signal an infection that needs attention.

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Dry Mouth

A dry mouth is most common after chemotherapy and radiation therapy to specific types of cancer such as the head or neck area. A dry mouth from a reduction in the flow of saliva can make it difficult to chew and swallow and may change the way food tastes.

  • Stimulate saliva by sucking on lemon-flavored sugar-free candies, frozen grapes or sugarless popsicles; sucking on ice chips or cubes; and trying tart foods and beverages, such as lemonade, in small amounts.
  • Opt for easy-to-swallow, moist foods such as those with broth, gravy, sauces and salad dressings.
  • Avoid salty foods and alcohol.
  • When drinking beverages: sip through a straw, and drink thick drinks such as fruit nectars at room temperature or colder.
  • Practice good oral hygiene. See tips under “Sore Mouth” relating to rinsing your mouth and brushing your teeth.
  • Keep your lips moist by applying ointment.
  • Try using a cool mist humidifier, especially at night.
  • Don’t smoke.
  • If your dry mouth is severe, ask your doctor or dentist about products that coat and protect your mouth and about saliva substitutes and stimulants.
  • Tell your health practitioner about any small, white patches in your mouth, which may signal an infection requiring care.

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Difficulty Swallowing

If you are being treated for a head or neck cancer, you may develop trouble swallowing. Talk to your doctor to determine if your treatment is the reason. You might need to have a swallowing assessment to determine which foods and liquids you can safely and effectively swallow.

  • Eat small, frequent meals.
  • Purée foods, or thin out mashed foods using broth, gravy, milk or water.
  • Take deep breaths before trying to swallow, and exhale or cough after swallowing.
  • Drink plenty of fluids, aiming for eight 8-ounce glasses a day. Liquids at room temperature may be easier to swallow. Drink beverages between rather than during meals so you don’t feel full too quickly.
  • Ask your speech therapist or registered dietitian for help with: properly placing food in your mouth to avoid choking; adjusting your dietary fiber to avoid constipation or diarrhea while on a liquid diet; and effective swallowing techniques if part or all of your tongue or jawbone has been removed.
  • Report any choking or coughing while eating to your doctor, especially if accompanied by a fever.

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Surgery or radiation therapy sometimes causes the esophagus to narrow, making it painful and difficult for food to pass through your chest area to the stomach. Your surgeon may be able to widen the opening or insert a feeding tube to bypass the constriction while it heals.

  • Try to drink liquids, which will pass through the esophagus more easily.
  • Elevate your head while eating or drinking lying down.

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Tooth Decay

Some cancer treatments can cause tooth decay and other problems for your teeth and gums. Some changes to your eating habits may make the problem worse.

  • See your dentist before starting treatment, especially if you have a history of tooth or gum problems, to help prevent infection or other problems.
  • See your dentist regularly – more often than usual if you’re receiving treatment that affects the mouth (such as radiation to the head and neck). Inform your dentist about all medications you are taking.
  • Use a soft toothbrush. Or, if your gums are sensitive, clean your teeth with cotton swabs or mouth swabs made especially for this purpose.
  • Rinse your mouth with warm water when your mouth and gums are sore. Also, rinse your mouth if you have vomited to remove acid.
  • Limit excess sugar and sticky/sweet foods in your diet unless you are experiencing poor appetite or difficultly maintaining your weight.
  • Brush or rinse your mouth after each time you eat.

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