Last Modified : 2006-06-19
Cancer and cancer treatments may cause nutrition-related side effects.
The diet is an important part of cancer treatment. Eating the right kinds of foods before, during, and after treatment can help the patient feel better and stay stronger. To ensure proper nutrition, a person has to eat and drink enough of the foods that contain key nutrients (vitamins, minerals, protein, carbohydrates, fat, and water). For many patients, however, some side effects of cancer and cancer treatments make it difficult to eat well. Symptoms that interfere with eating include anorexia, nausea, vomiting, diarrhea, constipation, mouth sores, trouble with swallowing, and pain. Appetite, taste, smell, and the ability to eat enough food or absorb the nutrients from food may be affected. Malnutrition (lack of key nutrients) can result, causing the patient to be weak, tired, and unable to resist infections or withstand cancer therapies. Eating too little protein and calories is the most common nutrition problem facing many cancer patients. Protein and calories are important for healing, fighting infection, and providing energy.
Anorexia and cachexia are common causes of malnutrition in cancer patients.
Anorexia (the loss of appetite or desire to eat) is a common symptom in people with cancer. Anorexia may occur early in the disease or later, when the tumor grows and spreads. Some patients may have anorexia when they are diagnosed with cancer. Almost all patients who have widespread cancer will develop anorexia. Anorexia is the most common cause of malnutrition in cancer patients.
Cachexia is a wasting syndrome that causes weakness and a loss of weight, fat, and muscle. It commonly occurs in patients with tumors of the lung, pancreas, and upper gastrointestinal tract and less often in patients with breast cancer or lower gastrointestinal cancer. Anorexia and cachexia often occur together. Weight loss can be caused by eating fewer calories, using more calories, or a combination of the two. Cachexia can occur in people who are eating enough, but who cannot absorb the nutrients. Cachexia is not related to the tumor size, type, or extent. Cancer cachexia is not the same as starvation. A healthy person's body can adjust to starvation by slowing down its use of nutrients, but in cancer patients, the body does not make this adjustment.
Good eating habits during cancer care help the patient cope with the effects of the cancer and its treatment.
Nutrition therapy can help cancer patients get the nutrients needed to maintain body weight and strength, prevent body tissue from breaking down, rebuild tissue, and fight infection. Eating guidelines for cancer patients can be very different from the usual suggestions for healthful eating. Nutrition recommendations for cancer patients are designed to help the patient cope with the effects of the cancer and its treatment. Some cancer treatments are more effective if the patient is well nourished and getting enough calories and protein in the diet. People who eat well during cancer treatment may even be able to handle higher doses of certain treatments. Being well-nourished has been linked to a better prognosis (chance of recovery).
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Cancer can change the way the body uses food.
Tumors may produce chemicals that change the way the body uses certain nutrients. The body's use of protein, carbohydrates, and fat may be affected, especially by tumors of the stomach or intestines. A patient may appear to be eating enough, but the body may not be able to absorb all the nutrients from the food. Diets higher in protein and calories can help correct this and prevent the onset of cachexia. Drugs may also be helpful. It is important to monitor nutrition early, as cachexia is difficult to completely reverse.
Drugs may help relieve cancer symptoms and side effects that cause weight loss.
Early treatment of cancer symptoms and side effects that affect eating and cause weight loss is important. Both nutrition therapy and drugs can help the patient maintain a healthy weight. The types of drugs commonly used to relieve these symptoms and side effects include the following:
(Refer to the Nutrition Screening and Assessment section and the Nutrition Suggestions for Symptom Relief section for more information.)
Surgery increases the body's need for nutrients and energy.
The body needs extra energy and nutrients to heal wounds, fight infection, and recover from surgery. If the patient is malnourished before surgery, there may be complications during recovery, such as poor healing or infection. Patients with certain cancers, such as cancers of the head, neck, stomach, and intestines, may be malnourished at diagnosis. Nutrition care may therefore begin before surgery.
Nutrition-related side effects may occur as a result of surgery.
More than half of cancer patients have cancer-related surgery. Surgery may include the removal of all or parts of certain organs, which may affect a patient's ability to eat and digest food. The following are nutrition problems related to specific surgeries:
Nutrition therapy can treat these problems and help cancer patients get the nutrients they need.
Nutrition therapy can treat the nutrition-related side effects of surgery.
Nutrition therapy may include the following:
Surgery may cause fatigue, pain, and loss of appetite.
It is common for patients to experience pain, tiredness, and/or loss of appetite after surgery. For a short time, some patients may not be able to eat their regular diet because of these symptoms. The following eating tips may help:
Chemotherapy may affect the whole body.
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. Because chemotherapy targets rapidly dividing cells, healthy cells that normally grow and divide rapidly may also be affected by the cancer treatments. These include cells in the mouth and digestive tract.
Nutrition-related side effects may occur during chemotherapy.
Side effects that interfere with eating and digestion may occur during chemotherapy. The following side effects are common:
Nutrition therapy can treat the nutrition-related side effects of chemotherapy.
The side effects of chemotherapy may make it difficult for a patient to obtain the nutrients needed to regain healthy blood counts between chemotherapy treatments. Nutrition therapy can treat these side effects and help chemotherapy patients get the nutrients they need to tolerate and recover from treatment, prevent weight loss, and maintain general health. Nutrition therapy may include the following:
Radiation therapy can affect healthy cells in the treatment area.
Radiation therapy is a cancer treatment that uses high energy x-rays or other types of radiation to kill cancer cells. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.
Healthy cells that are near the cancer may be affected by the radiation treatments, and side effects may occur. The side effects depend mostly on the radiation dose and the part of the body that is treated.
Nutrition-related side effects may occur during radiation therapy.
Radiation therapy to any part of the digestive system is likely to cause nutrition-related side effects. The following side effects may occur:
Nutrition therapy can treat the nutrition-related side effects of radiation therapy.
Nutrition therapy during radiation treatment can provide the patient with enough protein and calories to tolerate the treatment, prevent weight loss, and maintain general health. Nutrition therapy may include the following:
Nutrition-related side effects may occur during immunotherapy.
Immunotherapy is treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer. This type of cancer treatment is also called biologic therapy or biotherapy.
The following nutrition-related side effects are common during immunotherapy:
Nutrition therapy can treat the nutrition-related side effects of immunotherapy.
If the side effects of immunotherapy are not treated, weight loss and malnutrition may occur. These conditions can cause complications during recovery, such as poor healing or infection. Nutrition therapy can treat side effects from immunotherapy and help patients get the nutrients they need to tolerate treatment, prevent weight loss, and maintain general health.
Bone marrow and stem cell transplant patients have special nutritional needs.
Bone marrow and stem cell transplantation are methods of replacing blood-forming cells destroyed by cancer treatment with high doses of chemotherapy or radiation therapy. Stem cells (immature blood cells) are removed from the bone marrow of the patient or a donor and are frozen for storage. After the chemotherapy and radiation therapy are completed, the stored stem cells are thawed and given back to the patient through an infusion. Over a short time, these reinfused stem cells grow into (and restore) the body’s blood cells.
Chemotherapy, radiation therapy, and medications used in the transplant process may cause side effects that prevent a patient from eating and digesting food as usual. These side effects include the following:
Transplant patients also have a very high risk of infection. The high doses of chemotherapy and radiation therapy reduce the number of white blood cells, the cells that fight infection. Cancer patients should be especially careful to avoid infections and food-borne illnesses. Patients are advised to avoid eating certain foods that may carry harmful bacteria.
Nutrition therapy can treat the nutrition-related side effects of bone marrow and stem cell transplantation.
Patients undergoing the transplant process need adequate protein and calories to tolerate and recover from the treatment, prevent weight loss, fight infection, and maintain general health. Nutrition therapy is also designed to avoid possible infection from bacteria in food. Nutrition therapy during the transplant process may include the following:
Finding and treating nutrition problems early may improve the patient's prognosis (chance of recovery).
Early nutrition screening and assessment can identify problems that affect the success of anticancer therapy. Patients who are underweight or malnourished may not respond well to cancer treatments. Malnutrition may be caused by the cancer or made worse as the cancer progresses. Finding and treating nutrition problems early may help the patient gain or maintain weight, improve the patient's response to therapy, and reduce complications of treatment.
Screening and assessment are done before beginning anticancer therapy, and assessment continues throughout treatment.
Because the ability to tolerate treatment is better for the well-nourished patient, screening and assessment are done before beginning anticancer therapy. Appropriate nutrition management is begun early, and nutritional status is checked often during treatment.
Screening is used to identify patients who may be at nutritional risk. Assessment determines the complete nutritional status of the patient and identifies if nutrition therapy is needed. The patient or caregiver may be asked for the following information:
A physical exam is part of the assessment. The physical exam will check the body for general health and signs of disease, such as lumps or growths. The physician will look for loss of weight, fat and muscle, and fluid buildup in the body.
Ongoing assessment is completed by a healthcare team with expertise in nutritional management.
A nutrition support team will monitor the patient's nutritional status during cancer treatment and recovery. The team may include the following specialists:
The goals of nutrition therapy for cancer patients in active treatment and recovery are designed to restore nutrient shortages, maintain nutritional health, and prevent complications.
The goals of nutrition therapy for patients in active treatment and recovery are to do the following:
A patient whose religion forbids eating certain foods may consider speaking with a religious leader about waiving the restriction during cancer treatment and recovery.
Good nutrition continues to be important for patients who are in remission or whose cancer has been cured.
The goals of nutrition therapy for patients who have advanced cancer are designed to improve the quality of life.
The goals of nutrition therapy for patients who have advanced cancer are to do the following:
Nutrition support provides nutrition to patients who cannot eat normally.
Eating by mouth is the preferred method and should be used whenever possible, but some patients may not be able to take any or enough food by mouth due to complications from cancer or cancer treatment. This may include patients with cancer of the head, neck, esophagus, or stomach. A patient may be fed using enteral nutrition (through a tube inserted into the stomach or intestine) or parenteral nutrition infused into the bloodstream directly). The nutrients are delivered in formulas, liquids that contain water, protein, fats, carbohydrates, vitamins, and/or minerals. The content of the formula depends on the needs of the patient and the method of feeding.
Nutritional support can improve a patient's quality of life during cancer, but there are risks and disadvantages that should be considered before making the decision to use it. The effect of nutritional support on tumor growth is not known. Also, each form of nutrition therapy has its own benefits and disadvantages. For example, enteral nutrition keeps the stomach and intestines working normally and has fewer complications than parenteral nutrition; nutrients are used more easily by the body in enteral feeding. These and other issues should be discussed with the patient's health care providers so that an informed decision can be made. (See the Advanced Cancer section below for more information on deciding whether to use nutritional support.)
Patients with certain conditions are most appropriate for treatment with nutrition support.
Nutrition support may be helpful for patients who have one or more of the following characteristics:
Enteral nutrition is also called tube feeding.
Enteral nutrition is food (in liquid form) given to the patient through a tube that is inserted into the stomach or the small intestine. The following types of tube feeding may be used:
If the tube is placed in the stomach, food may be given through the tube continuously or in batches several times a day. If the tube is placed in the small intestine, the food is delivered continuously. Different formulas are available. Some provide complete nutrition and others provide certain nutrients. Formulas that meet the patient's specific needs are selected. Formulas are available for patients who have other health conditions, such as diabetes.
Enteral nutrition is sometimes used when the patient is able to eat small amounts by mouth but cannot obtain enough food that way. The patient may continue to eat or drink as able, and the tube feeding provides the balance of calories and nutrients that are needed.
Enteral nutrition may be appropriate for patients whose gastrointestinal tract is still working.
Enteral nutrition continues to use the stomach and/or intestines to digest food. Enteral nutrition may be used for patients who have cancer of the head, neck, or digestive system and whose treatment with chemotherapy and radiation therapy causes side effects that limit eating or drinking.
Enteral nutrition is not appropriate for the following patients:
Enteral nutrition may continue after a patient leaves the hospital.
If enteral nutrition is to be part of the patient's care after leaving the hospital, the patient and caregiver will be trained in use of the tube and pump, and in care of the patient. The home must be clean and the patient must be monitored often by the nutrition support team.
Parenteral nutrition provides the patient with nutrients delivered into the blood stream.
Parenteral nutrition is used when the patient cannot take food by mouth or by enteral feeding. Parenteral feeding bypasses the normal digestive system. Nutrients are delivered to the patient directly into the blood, through a catheter (thin tube) inserted into a vein. Patients with the following problems may benefit from parenteral nutrition:
The catheter may be placed into a vein in the chest or in the arm.
A central venous catheter is placed beneath the skin and into a large vein in the upper chest. Placement of a central venous catheter is done by a surgeon.
A peripheral venous catheter is placed into a vein in the arm. Placement of a peripheral venous catheter is done by trained medical staff. This site may be used for short-term parenteral feeding.
The patient is checked often for infection or bleeding at the site (place) where the catheter enters the body.
Some drugs should not be given with parenteral formulas.
Many drugs and other substances do not mix safely with the formulas used for parenteral feeding. A pharmacist or doctor should be consulted before adding anything to the formula or using the catheter for another substance.
Trained medical staff should manage the use of parenteral nutrition.
The techniques and formulas involved in parenteral nutrition support are precise and require management by trained medical staff or a nutrition support team. Some of the serious complications that may occur with parenteral feeding include the following:
Parenteral nutrition support may continue after a patient leaves the hospital.
If parenteral nutrition is to be part of the patient's care after leaving the hospital, the patient and caregiver will be trained in the procedures and in care of the patient. The home must be clean and the patient must be monitored often by the nutrition support team.
Experienced medical staff should manage the patient's removal from parenteral nutrition support.
Going off parenteral nutrition support needs to be done gradually and under medical supervision. The parenteral feedings are reduced by small amounts over time as the patient is changed to enteral or oral feeding.
When side effects of cancer or cancer treatment interfere with normal eating, adjustments can be made to ensure the patient continues to get the necessary nutrition. Medications may be given to stimulate the appetite. Eating foods that are high in calories, protein, vitamins and minerals is usually advised. Meal planning, however, should be individualized to meet the patient's nutritional needs and tastes in food.
Anorexia (lack of appetite) is one of the most common problems for cancer patients. The following suggestions may help cancer patients manage anorexia:
The following high-calorie, high-protein foods are recommended:
See the NCI Web site's Eating Hints for Cancer Patients: Before, During, and After Treatment for recipes such as Lactose-Free Double Chocolate Pudding, Banana Milkshake, and Fruit and Cream. For a free copy of this booklet, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
Changes in how foods taste may be caused by radiation treatment, dental problems, or medicines. Cancer patients often complain of changes in their sense of taste when undergoing chemotherapy, in particular a bitter taste sensation. A sudden dislike for certain foods may occur. This may result in food avoidance, weight loss, and anorexia, which can greatly reduce the patients' quality of life. Some or all of the sense of taste may return, but it may be a year after treatment ends before the sense of taste is normal again. Drinking plenty of fluids, changing the types of foods eaten and adding spices or flavorings to food may help.
The following suggestions may help cancer patients manage changes in taste:
Taking zinc sulfate tablets during radiation therapy to the head and neck may speed the return of normal taste after treatment.
Dry mouth is often caused by radiation therapy to the head and neck. Some medicines may also cause dry mouth. Dry mouth may affect speech, taste, ability to swallow, and the use of dentures or braces. There is also an increased risk of cavities and gum disease because less saliva is produced to wash the teeth and gums.
The main treatment for dry mouth is drinking plenty of liquids, about ½ ounce per pound of body weight per day. Other suggestions to manage dry mouth include the following:
(Refer to the PDQ summary on Oral Complications of Chemotherapy and Head/Neck Radiation for more information on dry mouth.
Mouth sores can result from chemotherapy and radiation therapy. These treatments target rapidly-growing cells because cancer cells grow rapidly. Normal cells inside the mouth may be damaged by these cancer treatments because they also grow rapidly. Mouth sores may become infected and bleed, making eating difficult. By choosing certain foods and taking good care of their mouths, patients can usually make eating easier. Suggestions to help manage mouth sores and infections include the following:
Using a mouth rinse that contains glutamine may reduce the number of mouth sores. Glutamine is a substance found in plant and animal proteins.
(Refer to the PDQ summary on Oral Complications of Chemotherapy and Head/Neck Radiation for more information on mouth sores and infections.)
Nausea caused by cancer treatment can affect the amount and kinds of food eaten. The following suggestions may help cancer patients manage nausea:
(Refer to the PDQ summary on Nausea and Vomiting for more information.)
Diarrhea may be caused by cancer treatments, surgery on the stomach or intestines, or by emotional stress. Long-term diarrhea may lead to dehydration (lack of water in the body) and/or low levels of salt and potassium, important minerals needed by the body.
The following suggestions may help cancer patients manage diarrhea:
Taking oral glutamine may help keep the intestines healthy when taking the anticancer drug fluorouracil.
(Refer to the PDQ summary on Gastrointestinal Complications for more information.)
Cancer patients may have a low white blood cell count for a variety of reasons, some of which include radiation therapy, chemotherapy, or the cancer itself. Patients who have a low white blood cell count are at an increased risk of infection. The following suggestions may help cancer patients prevent infections when white blood cell counts are low:
Hot flashes occur in most women with breast cancer and men with prostate cancer. When caused by natural or treatment-related menopause, hot flashes can be relieved with estrogen replacement. Many women, however, (including women with breast cancer), are not able to take estrogen replacement. Eating soy foods, which contain an estrogen-like substance, is sometimes suggested to relieve hot flashes in patients who cannot take estrogen replacement, but no benefit has been proven. (Refer to the PDQ summary on Fever, Sweats, and Hot Flashes for more information.)
The body needs plenty of water to replace the fluids lost every day. Long-term diarrhea, nausea and vomiting, and pain may prevent the patient from drinking and eating enough to get the water needed by the body. One of the first signs of dehydration (lack of water in the body) is extreme tiredness. The following suggestions may help cancer patients prevent dehydration:
Constipation is defined as fewer than 3 bowel movements per week. It is a very common problem for cancer patients and may result from lack of water or fiber in the diet; lack of physical activity; anticancer therapies such as chemotherapy; and medications.
Prevention of constipation is a part of cancer care. The following suggestions may help cancer patients prevent constipation:
If constipation does occur, the following suggestions for diet, exercise, and medication may help correct it:
Good food sources of fiber include the following:
4 or more grams of fiber per servingLegumes, broccoli, and cabbage may cause gas. Over-the-counter enzyme tablets may be helpful.
Nutrition-related side effects may occur or become worse as cancer becomes more advanced.
The following are the most common nutrition-related symptoms in patients who have advanced cancer:
The usual treatment for these problems in patients with advanced cancer is palliative care to reduce the symptoms and improve the quality of life.
Palliative care includes nutrition therapy (see the Nutrition Suggestions for Symptom Relief section) and/or drug therapy (see the Drug-Nutrient Interactions section).
Eating less solid food is common in advanced cancer. Patients usually prefer soft foods and clear liquids. Those who have problems swallowing may do better with thick liquids than with thin liquids. Terminally ill patients often do not feel much hunger at all and may be satisfied with very little food.
When cancer is advanced, food should be viewed as a source of enjoyment. Eating should not just be about calories, protein, and other nutrient needs.
Dietary restriction is not usually necessary, as intake of “prohibited foods” (such as sweets for a patient with diabetes) is not enough to be of concern. Some patients, however, may need certain diet restrictions. For example, patients who have pancreatic cancer, uterine cancer, ovarian cancer, or another cancer affecting the abdominal area may need a soft diet (no raw fruits and vegetables, no nuts, no skins, no seeds) to prevent a blockage in the bowel. Diet restrictions should be considered in terms of