There are many benefits to this. In the short term, eating well can: give you energy help you feel better keep your body strong help you cope with side effects.

Over the long term, eating well can: help you heal and recover after treatment lower your risk of heart disease, type 2 diabetes and osteoporosis weakening of the bones lower your risk of some types of cancer.

Eating well can also help you feel like you have some control over your own health. And we now know that people with cancer who are well nourished and able to maintain a healthy body weight live longer than people who have lost a lot of weight. In general, eating well means eating a variety of healthy foods like vegetables and fruit, whole grains and protein.

A registered dietitian can help you find ways to eat well and maintain a healthy body weight throughout your cancer experience. Your dietitian can help you make sure that you get the right amount of calories, protein and fluids that you need to eat well.

Good sources of calories include whole fat dairy products like milk, yogurt and cheese, and healthy fats like olive oil, avocados, nuts and nut butters.

Protein is good for your health in many ways. It helps your body grow cells, heal tissue and maintain a healthy immune system.

And it can help you avoid infection and recover more quickly. The key is to know where to find it. Good sources of protein include fish, poultry, lean red meat, eggs, nuts and nut butters, dried beans, peas and lentils, dairy products and soy foods.

Yet every cell in your body needs water. They can provide much-needed calories and keep you from becoming dehydrated. Do your best to drink plenty of water and other fluids each day. Your dietitian can give you specific guidelines on how much is right for you.

Alcohol can interfere with some cancer treatments and medicines. It can make side effects like a sore mouth and throat worse. And we now know that drinking any type of alcohol increases your risk of developing some types of cancer.

The best way to get vitamins or minerals is to eat a well-balanced diet. If you do that, you usually get what you need to stay healthy. Taking a regular-strength multivitamin and mineral supplement for your age group every day is often OK, but check with your healthcare team just to be sure.

There is no evidence that taking more than the recommended amounts of vitamins and minerals or that taking large amounts megadoses of any vitamin or mineral will improve your health or help to prevent or cure cancer. In fact, taking too much of some types of vitamins or minerals can be harmful to your health — and it may even make cancer treatment less effective.

Many people wonder whether eating specific foods will boost their immune system and help them fight cancer. No single diet, food or supplement can boost your immune system.

The best thing you can do for your immune system is to follow an overall healthy lifestyle, which includes eating a balanced, healthy diet with a variety of foods. There is no scientific evidence that any specific food or diet for example, the alkaline diet, a macrobiotic diet or the Gerson therapy diet can cure cancer.

Because these diets often restrict food choices like meat, milk, eggs and even vegetables and fruit , they may not provide enough calories, protein, vitamins and minerals. This can lead to weight loss and poor nutrition. Eating-related side effects are common during cancer treatment.

But most of the time you may not eat well because cancer treatments can damage healthy cells along with cancer cells, causing side effects. And when you have them, it can take some time to figure out what will help.

You may find that your ability to eat well varies from one day to the next. This can all be pretty frustrating. The good news is that most of the time, side effects related to eating are temporary. Once treatment ends, many people gradually get back to eating normally again. Find out more about these eating-related side effects: constipation diarrhea difficulty swallowing dry mouth dumping syndrome fatigue loss of appetite nausea and vomiting osteoporosis sore mouth and throat taste changes trismus weight gain.

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on cancer.

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Most of the side effects begin two to three weeks after radiation therapy begins and go away a few weeks after it is finished. Some side effects can continue for months or years after treatment ends. Radiation therapy may also cause tiredness, which can lead to a decrease in appetite.

The body needs extra energy and nutrients to heal wounds , fight infection , and recover from surgery. If someone is malnourished before surgery, they may have trouble healing. For these people, nutrition care may begin before surgery.

Most people with cancer are treated with surgery. Surgery that removes all or part of certain organs can affect a person's ability to eat and digest food.

The side effects of immunotherapy are different for each person and the type of immunotherapy drug given. Chemotherapy, radiation therapy, and other medicines used before or during a stem cell transplant may cause side effects that keep a person from eating and digesting food as usual.

People who receive a stem cell transplant have a high risk of infection. Chemotherapy or radiation therapy given before the transplant decrease the number of white blood cells , which fight infection.

It is important that these people learn about safe food handling and avoid foods that may cause infection. After a stem cell transplant, people are at risk for acute or chronic graft-versus-host disease GVHD. GVHD may affect the gastrointestinal tract or liver and change the person's ability to eat or absorb nutrients from food.

Screening is used to look for health problems that affect the risk of poor nutrition. This can help find out if you are likely to become malnourished , and if nutrition therapy is needed. A physical exam is done. Your doctor will check for signs of weight, fat, and muscle loss, and for fluid buildup in your body.

A registered dietitian can counsel you and your family on ways to improve your nutrition. The registered dietitian gives care based on your nutritional and dietary needs during cancer treatment and recovery. Changes to the diet are made to help decrease symptoms from cancer or cancer treatment.

These changes may be in the types and amount of food, how often you eat, and how food is eaten for example, at a certain temperature or taken with a straw. In addition to the dietitian, the healthcare team may include the following:. The goal of nutrition therapy in people with advanced cancer is to provide the best possible quality of life and control symptoms that cause distress.

People with advanced cancer may be treated with anticancer therapy and palliative care , palliative care alone, or may be in hospice care. Nutrition goals will be different for each person. Some types of treatment may be stopped.

As the focus of care goes from cancer treatment to hospice or end-of-life care , nutrition therapy may become less aggressive to keep the person as comfortable as possible.

For more information, see the Nutrition Needs at End of Life section. When side effects of cancer or cancer treatment affect normal eating, changes can be made to help you get the nutrients you need.

Eating foods that are high in calories , protein , vitamins , and minerals is important. Meals should be planned to meet your nutritional needs and tastes in food. The following are common symptoms caused by cancer and cancer treatment and ways to treat or control them.

The following may help people with cancer who have anorexia loss of appetite or desire to eat :. If these diet changes do not help with the anorexia, tube feedings may be needed. Medicines may be given to increase appetite. For more information, see the Medicines to Treat Loss of Appetite and Weight Loss section.

The following may help people with cancer who have a sore throat or trouble swallowing:. The following may help people with cancer who have symptoms of lactose intolerance :. It is best to take in food by mouth whenever possible.

Some people may not be able to take in enough food by mouth because of problems from cancer or cancer treatment. In addition to counseling by a dietitian and changes to the diet , nutrition therapy includes nutritional supplement drinks and enteral and parenteral nutrition support.

Nutritional supplement drinks help people with cancer get the nutrients they need. They provide energy, protein , fat, carbohydrates , fiber , vitamins , and minerals. They are not meant to be the person's only source of nutrition. A person who is not able to take in the right amount of calories and nutrients by mouth may be fed using the following:.

Nutrition support can improve a person's quality of life during cancer treatment, but may cause problems that should be considered before making the decision to use it.

The patient, family, and healthcare team should discuss the harms and benefits of each type of nutrition support. For more information on the use of nutrition support at the end of life, see the Nutrition Needs at End of Life section.

Enteral nutrition gives the patient nutrients in liquid form formula through a tube that is placed into the stomach or small intestine. The following types of feeding tubes may be used:. The type of formula used is based on the person's specific needs.

There are formulas for people who have special health conditions , such as diabetes , or other needs, such as religious or cultural diets. Parenteral nutrition is used when a person cannot take food by mouth or by enteral feeding. Parenteral feeding does not use the stomach or intestines to digest food.

Nutrients are given to the patient directly into the blood , through a catheter inserted into a vein. These nutrients include proteins, fats, vitamins, and minerals.

A central venous access catheter is placed beneath the skin and into a large vein in the upper chest. The catheter is put in place by a surgeon. This type of catheter is used for long-term parenteral feeding.

Enlarge Central venous catheter. A central venous catheter is a thin, flexible tube that is inserted into a vein, usually below the right collarbone, and guided threaded into a large vein above the right side of the heart called the superior vena cava.

It is used to give intravenous fluids, blood transfusions, chemotherapy, and other drugs. The catheter is also used for taking blood samples.

It may stay in place for weeks or months and helps avoid the need for repeated needle sticks. A peripheral venous catheter is placed into a vein in the arm. A peripheral venous catheter is put in place by trained medical staff.

This type of catheter is usually used for short-term parenteral feeding for patients who do not have a central venous access catheter. Enlarge Peripheral venous catheter. A peripheral venous catheter is a thin, flexible tube that is inserted into a vein. It is usually inserted into the lower part of the arm or the back of the hand.

The patient is checked often for infection or bleeding at the place where the catheter enters the body. It is important that cancer symptoms and side effects that affect eating and cause weight loss are treated early. Both nutrition therapy and medicine can help lessen the effects that cancer and its treatment have on weight loss.

Medicines that improve appetite and cause weight gain, such as prednisone and megestrol , may be used to treat loss of appetite and weight loss.

Studies have shown that the effects of these medicines may not last long, or there may be no effects. Treatment with a combination of medicines may work better than treatment with one medicine but may have more side effects.

For people at the end of life, the goals of nutrition therapy are focused on relieving symptoms rather than getting enough nutrients. People who have problems swallowing may find it easier to swallow thick liquids than thin liquids.

People with cancer often do not feel much hunger at all and may want very little food. Sips of water, ice chips, and mouth care can decrease thirst in the last few days of life. Good communication with the healthcare team is important to understand the patient's changes in nutrition needs.

People with cancer and their caregivers have the right to make informed decisions. The person's religious and cultural preferences may affect their decisions.

The healthcare team may work with the person's religious and cultural leaders when making decisions. The healthcare team and a registered dietitian can explain the benefits and risks of using nutrition support for people at the end of life.

In most cases, there are more harms than benefits if the person is not expected to live longer than a month. Possible benefits of nutrition support for people expected to live longer than a month include the following:.

People with cancer may try special diets to make their treatment work better, prevent side effects from treatment, or to treat the cancer itself. However, for most of these special diets, there is no evidence that shows they work.

It is not known if following a vegetarian or vegan diet can help side effects from cancer treatment or the person's prognosis. If the person already follows a vegetarian or vegan diet, there is no evidence that shows they should switch to a different diet. A macrobiotic diet is a high- carbohydrate , low-fat, plant-based diet.

No studies have shown that this diet will help people with cancer. A ketogenic diet limits carbohydrates and increases fat intake. The purpose of the diet is to decrease the amount of glucose sugar the tumor cells can use to grow and reproduce.

It is a hard diet to follow because exact amounts of fats, carbohydrates, and proteins are needed. Several clinical trials are recruiting people with glioblastoma to study whether a ketogenic diet affects glioblastoma tumor activity.

People with glioblastoma who want to start a ketogenic diet should talk to their doctor and work with a registered dietitian. However, it is not yet known how the diet will affect the tumor or its symptoms.

Similarly, a study comparing the ketogenic diet to a high-fiber, low fat diet in women with ovarian cancer or endometrial cancer found that the ketogenic diet was safe and acceptable. There is not enough evidence to know how the ketogenic diet will affect ovarian or endometrial tumors or their symptoms.

A dietary supplement is a product that is added to the diet. It is usually taken by mouth, and usually has one or more dietary ingredients. People with cancer may take dietary supplements to improve their symptoms or treat their cancer.

Vitamin C is a nutrient that the body needs in small amounts to function and stay healthy. It helps fight infection , heal wounds, and keep tissues healthy. Vitamin C is found in fruits and vegetables. It can also be taken as a dietary supplement. For information about the use of intravenous vitamin C as treatment for people with cancer, see Intravenous Vitamin C.

Probiotics are live microorganisms used as dietary supplements to help with digestion and normal bowel function. They may also help keep the gastrointestinal tract healthy. Studies have shown that taking probiotics during radiation therapy and chemotherapy can help prevent diarrhea caused by those treatments.

People with cancer who are receiving radiation therapy to the abdomen or chemotherapy that is known to cause diarrhea may be helped by probiotics.

Similarly, studies are looking at potential benefits of taking probiotics for people with cancer who are receiving immunotherapy. Melatonin is a hormone made by the pineal gland tiny organ near the center of the brain.

Melatonin helps control the body's sleep cycle. It can also be made in a laboratory and taken as a dietary supplement. It may help reduce side effects of treatment. Melatonin does not appear to have side effects.

Oral glutamine is an amino acid that is being studied for the treatment of diarrhea and mucositis inflammation of the lining of the digestive system , often seen as mouth sores caused by chemotherapy or radiation therapy.

Oral glutamine may help prevent mucositis or make it less severe. People with cancer who are receiving radiation therapy to the abdomen may benefit from oral glutamine.

Oral glutamine may reduce the severity of diarrhea. This can help people continue with their treatment plan. For information from the National Cancer Institute NCI about nutrition and cancer treatment, see Side Effects. For general nutrition information and other resources, see the following:.

Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done.

General information about clinical trials is also available. Physician Data Query PDQ is the National Cancer Institute's NCI's comprehensive cancer information database.

The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language.

The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health NIH. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH. This PDQ cancer information summary has current information about nutrition before, during, and after cancer treatment.

It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care. Editorial Boards write the PDQ cancer information summaries and keep them up to date.

These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information.

The date on each summary "Updated" is the date of the most recent change. The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Supportive and Palliative Care Editorial Board.

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory.

Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard.

Some clinical trials are open only to patients who have not started treatment. Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service CIS , NCI's contact center, at CANCER PDQ is a registered trademark. The content of PDQ documents can be used freely as text.

It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. PDQ® Supportive and Palliative Care Editorial Board. PDQ Nutrition in Cancer Care. Bethesda, MD: National Cancer Institute. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner.

It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 3, scientific images. The information in these summaries should not be used to make decisions about insurance reimbursement.

More information on insurance coverage is available on Cancer. gov on the Managing Cancer Care page. More information about contacting us or receiving help with the Cancer. gov website can be found on our Contact Us for Help page.

Questions can also be submitted to Cancer. Home About Cancer Cancer Treatment Side Effects of Cancer Treatment Appetite Loss Nutrition in Cancer Care PDQ® —Patient Version. Nutrition in Cancer Care PDQ® —Patient Version On This Page Overview of Nutrition in Cancer Care Effects of Cancer Treatment on Nutrition Nutrition Assessment in Cancer Care Treatment of Symptoms Types of Nutrition Support Medicines to Treat Loss of Appetite and Weight Loss Nutrition Needs at End of Life Nutrition Trends in Cancer To Learn More About Nutrition and Cancer Care Current Clinical Trials About This PDQ Summary Overview of Nutrition in Cancer Care Go to Health Professional Version.

Key Points Good nutrition is important for people with cancer. Nutrition goals are set for each person with cancer. A registered dietitian is an important part of the healthcare team. Cancer and cancer treatments may cause side effects that affect nutrition.

Cancer and cancer treatments may cause malnutrition. Anorexia and cachexia are common causes of malnutrition in people with cancer. Hormone therapy. Radiation therapy.

Stem cell transplant. Key Points Chemotherapy and Hormone Therapy Chemotherapy and hormone therapy affect nutrition in different ways. Chemotherapy and hormone therapy cause different nutrition problems.

Radiation Therapy Radiation therapy kills cells in the treatment area. Radiation therapy may affect nutrition. Surgery Surgery increases the body's need for nutrients and energy. Surgery to the head, neck, esophagus, stomach, or intestines may affect nutrition.

Immunotherapy Immunotherapy may affect nutrition. Stem Cell Transplant People who receive a stem cell transplant have special nutrition needs. Loss of appetite. Dry mouth. Sores in the mouth or throat. Changes in the way food tastes. Trouble swallowing. Feeling full after eating a small amount of food.

The part of the body that is treated. The total dose of radiation and how it is given. For radiation therapy to the brain or head and neck Loss of appetite. Dry mouth or thick saliva. Medication may be given to treat a dry mouth.