Nutrition for cancer patients: How to fuel your body for the fight

Nutrition for cancer patients
What should you eat during cancer treatment? Are you at risk for malnutrition? This article answers your questions about nutrition for cancer patients.

When you think about fighting cancer, nutrition may not be the first thing that pops into your mind. Cancer prevention campaigns promote a healthy diet as one means of lowering your risk of developing cancer. But what about after a cancer diagnosis? Does nutrition and eating well play a role?

After a cancer diagnosis, patients—or their family and friends—often start thinking about how food may affect cancer and its treatment. Well-meaning friends may advise you to follow a certain diet, to avoid eating certain foods or to include various herbs or dietary supplements in your diet. You may search the internet for information, but what you find there can be confusing, conflicting and overwhelming. It’s hard to know who to trust. Patients often come to us with questions, like:

  • Should I eat only organic or non-GMO foods?
  • What about a ketogenic diet? Would that help?
  • Should I go vegan?
  • Are there dietary supplements I should take?
  • Does sugar feed cancer?

While these are good questions, these concerns should be secondary to the primary goal of nutrition during cancer treatment: maintaining your ability to tolerate treatment and prepare for survivorship. 

Many patients don’t know whether they’re at risk for malnutrition or dehydration, and they’re not aware that those conditions may affect their ability to complete treatment. In fact, undernourishment—not getting enough food or healthy nutrients—is a serious concern for many patients. It’s a common repercussion of certain cancer treatments and their side effects

On the other hand, overnutrition (taking in more food than is necessary) creates problems, too. Obesity as a risk factor may also negatively impact treatment and may be associated with lower survival rates for some types of cancer, including breast cancer and prostate cancer. In some cases, it may also lead to an increased risk of cancer recurrence or of developing another cancer. 

Good nutrition for cancer patients has the competing goals of quantity and quality: getting the right kinds of nutrients in the right amounts. To help you navigate nutrition during cancer treatment, this post will cover:

If you’d like to learn more about nutritional support during cancer treatment or our integrative approach to cancer care at Cancer Treatment Centers of America® (CTCA), call us or chat online with a member of our team.

Why is good nutrition during cancer treatment important?

Adequate nutritional intake is important for maintaining energy levels, muscle mass and a healthy weight during and after treatment, and that in turn may improve your treatment tolerance and reduce the risk of adverse treatment side effects. According to the American Cancer Society, proper nutrition during treatment supports your immune system, which may lower your risk of infection and help you heal and recover faster. Nutritional deficiencies often contribute to fatigue and a reduced quality of life during treatment.

Sometimes, people who’ve struggled with weight for a long time start dropping a few pounds during treatment and don’t think it’s a problem. But even small amounts of weight loss may increase your risk of experiencing treatment side effects and may even mean that your treatment dose has to be adjusted or interrupted. Severe malnutrition or dehydration may lead to hospitalization and/or lengthier hospital stays when hospitalization is necessary.

Energy for physical activity

If you lose weight during treatment, you may be losing strength and muscle mass rather than stored fat. Maintaining your weight and energy levels with good nutrition helps provide you with the stamina to stay physically active and to continue your activities of daily living. The American Society of Clinical Oncology provides guidelines on how to exercise safely during treatment and lists many other possible benefits of exercise during and after treatment, including:

  • Lowering your risk of treatment-related side effects
  • Reducing the risk of depression and anxiety
  • Improving sleep quality
  • Reducing the risk of developing other chronic diseases, including other cancers

If possible, try to include some aerobic exercise and resistance training among your activities. Stretching, balance and breathing exercises may also be helpful. 

Support for the immune system

Cancer treatment may compromise the immune system. Chemotherapy may attack healthy cells in addition to cancer cells. Surgery may strain the immune system as the body tries to prevent infection and heal surgical wounds. And while radiation therapy has become more precise in recent years, treatment may still damage some healthy cells. Some treatments may also lead to conditions that lower the production of blood cells, including white blood cells, impairing the body’s ability to fight infection.

If you’re malnourished, and particularly if you're not getting enough calories or protein to maintain your weight, there's a good chance it’s negatively impacting your immune function. 

Preparation for survivorship

The benefits of developing a healthier diet and exercise habits during treatment may carry over into survivorship. According to the National Cancer Institute, research suggests that these healthier behaviors may improve the quality and length of life of some cancer survivors. 

The American Institute for Cancer Research advises cancer survivors to implement their 10 Cancer Prevention Recommendations, which include maintaining a healthy body weight, getting enough physical activity and other dietary recommendations. Following these guidelines may also reduce obesity, which has been associated with an increased risk of developing 13 cancer types and a recurrence of some cancers, such as breast cancer. A healthier lifestyle may also help you manage or prevent other chronic illnesses, such as heart disease or diabetes.

At CTCA®, we understand the importance of preparation for survivorship. We offer diet, exercise and healthy lifestyle guidance to our patients through our survivorship support program after primary treatment is completed. This program supplements the services we provide during treatment through our integrative care therapies, which include nutritional support, naturopathic support, oncology rehabilitation and pain management, to help reduce and manage the effects of cancer and treatment side effects.

What should you eat during cancer treatment?

Nutrition for cancer patients

The challenge of nutrition during cancer treatment is balancing the right quantity and quality of food and nutrient intake given your specific cancer type, treatment and side effects you may experience.

Guidelines for a healthy diet during cancer treatment are similar to those recommended for the general population: a balanced, plant-forward diet with whole grains, healthy sources of protein, fruits, vegetables and micronutrients. Try to include:

  • Whole grains like whole-wheat, brown rice, quinoa and buckwheat
  • Two to three cups of vegetables daily
  • One to two cups of fruits daily
  • Skinless poultry and cold water ocean fish like salmon, tuna and cod a couple of times per week
  • Dried beans, peas, lentils and legumes for additional protein
  • Healthy fats like olive oil, avocado, nuts and seeds
  • Low-fat dairy or a dairy substitute for calcium
  • Clean water

Try to reduce your consumption of red meat, processed meats, refined carbohydrates and added sugar. 

At the same time, don’t worry if you sometimes eat foods that aren’t considered to be healthy. It’s okay to have a hot dog or some ice cream because that’s the only thing that sounds good.

Check with your care team about your specific dietary needs

Ask your care team about dietary recommendations that may be associated with your specific type of cancer, treatment or treatment side effects. For example, if you have a bowel obstruction, limiting fiber intake may be important. Because chemotherapy comes with a high risk of nausea and vomiting, patients may be advised to modify what they eat and add some oral nutrition supplements. 

Patients often ask about the use of supplements. With proper guidance, some may be useful in helping to manage treatment side effects, but supplements shouldn’t be used to compensate for a poor diet. Some supplements may actually be harmful or cause unexplained symptoms. 

Pay extra attention to food safety during cancer treatment

Depending on your treatment, you may be immunocompromised. Some treatments are likely to affect your white blood cell count or neutrophil counts, which may put you at higher risk for foodborne illness. During treatment, try to be diligent about following normal kitchen safety precautions, such as heating and storing foods to proper temperatures and being careful to sanitize cutting boards and avoid cross contamination. 

Common causes of malnutrition and dehydration in cancer patients

Even when patients are actively trying to eat well and stay hydrated, conditions caused by the cancer itself and side effects of treatment may lead to malnutrition and dehydration. A lack of appetite, nausea and difficulty swallowing are just a few of the more common symptoms that affect a patient’s nutritional status.

Cancers associated with a higher risk of malnutrition

The effects of the cancer itself may inhibit the body’s ability to ingest, digest, absorb and metabolize nutrients. 

Patients with gastrointestinal cancers are at higher risk of malnutrition because of associated difficulties with eating, swallowing and digestion. These cancers include:

Malnutrition is also common among patients with advanced lung cancer. Treatments for lung cancer may cause gastrointestinal symptoms and metabolic changes—including the production of cytokines—that may lead to anorexia (a severe loss of appetite) and weight and/or muscle loss. Lung cancer patients with this condition may benefit from an appetite stimulant or a feeding tube.

Treatment side effects that may cause malnutrition and dehydration

Side effects of cancer treatment that may lead to malnutrition and dehydration include:

  • Nausea and vomiting are commonly associated with chemotherapy and radiation therapy. The National Cancer Institute estimates that up to 80 percent of patients undergoing chemotherapy experience these side effects.
  • Loss of appetite may be more common with certain types of cancers, such as stomach, pancreatic, lung and ovarian cancers. It’s also a common side effect of some chemotherapy, radiation therapy and immunotherapy treatments. 
  • Mucositis develops from inflammation of the digestive tract that often results in painful ulcers (commonly called mouth sores) in the mouth, throat and gastrointestinal tract. Mucositis may be a side effect of chemotherapy or radiation therapy, especially for head and neck cancer treatment. Some targeted therapies and immunotherapy may also cause this side effect.
  • Dry mouth may result from radiation therapy targeting head and neck cancers and from some medications taken during chemotherapy. It may cause the salivary glands to underproduce saliva, which may change a patient’s sense of taste and cause difficulty swallowing.
  • Taste and smell changes may result from damage to the taste buds caused by chemotherapy, radiation therapy and surgical oncology. These changes may contribute to a loss of appetite.
  • Constipation and diarrhea are commonly associated with chemotherapy but may also be consequences of some pain medications, radiation therapy and surgical procedures.

Dehydration in cancer patients

The side effects that lead to malnutrition may also result in dehydration in cancer patients. Dehydration is an obvious concern if you’re vomiting and/or have diarrhea, but not eating and drinking enough may cause problems, too. 

Mild dehydration may cause symptoms such as fatigue, headaches, dry skin and constipation. Severe dehydration may cause low blood pressure, rapid heartbeat, fever, disorientation, confusion and shock. Frequent dehydration may cause urinary tract infections and kidney stones. 

Your treatment may be delayed or your treatment dose adjusted if you’re dehydrated, and patients with severe dehydration may have to be hospitalized. Untreated severe dehydration may even be life-threatening.

Even if you don’t think you’re at risk for dehydration, make a conscious effort to stay hydrated during treatment. Drinking eight cups of water a day is a standard recommendation, but the amount you need generally depends on your body weight. (To calculate that amount, divide your weight by two. Divide that result by eight to determine how many cups per day you need to drink.)

Warning signs of malnutrition and dehydration

At CTCA, we regularly monitor our patients for signs of malnutrition and dehydration and work to prevent these issues through our nutritional support services. If you’re not being monitored by your care team, it’s important to be aware of warning signs that may indicate you need to seek help. These include:

  • Weight loss
  • Inability to eat or drink as you normally would
  • Difficulty or painful swallowing
  • New swelling in your ankles or eyes
  • Constipation
  • Diarrhea
  • A decline in energy or activity levels
  • Coughing that develops when you’re eating (more common with head, neck or lung cancers)

Talk with your care team if you’re experiencing any of these symptoms. There may be medications available to help. You may also benefit from supportive therapies, such as nutritional support, oncology rehabilitation, pain management and/or naturopathic support

Where to find nutritional support during cancer treatment

Nutrition for cancer patients

It’s better to be proactive about nutrition than to be faced with a crisis. Working with a health care professional who can anticipate likely side effects and consequences of your treatment may help you prepare for and reduce the chances of experiencing nutritional deficiencies. That way, if you do start to encounter difficulties, you’ll be more likely to recognize them and have a plan in place. 

Getting access to nutritional support during treatment may not be easy, however. Up to 90 percent of cancer patients are treated in an outpatient facility, where they may not have access to a nutrition professional. Cancer centers that do have these clinicians on staff may have an insufficient number of registered dietitian nutritionists (RDNs) to meet the needs of all patients. 

Ask whether nutritional support services are available where you’re being treated. Also ask, before treatment if possible, whether anyone will be regularly screening you for malnutrition or other nutrition-related complications during treatment. 

Health care professionals with nutritional expertise who may provide nutritional support during cancer treatment include:

  • A dietitian who is a board-certified specialist in oncology nutrition (CSO) has what’s considered the highest level of formal education in oncology nutrition, compared to other dietitians. A CSO may have more knowledge of how specific treatments may affect cancer patients and of how to prepare for related side effects. Recognizing how critical these professionals are in a cancer patient’s treatment journey, and knowing they’re in short supply around the country, CTCA has made it a priority to hire as many CSOs as possible. Today, we have about 9-10 on staff.
  • A registered dietitian (RD) or a registered dietitian nutritionist (RDN) who works with cancer patients during treatment will likely also be helpful.
  • Some oncology nurses, physician’s assistants, physicians and nurse practitioners have a passion for nutrition and expertise in helping patients undergoing cancer treatment. If they have the time and are willing, they may be a good resource for nutritional support.

At CTCA, we understand the benefits of working proactively to prevent nutritional deficiencies. Our patients have the option of working with a registered dietitian throughout treatment. Our dietitians work with the rest of your care team to monitor your nutritional status and make recommendations to help you manage side effects you may experience during treatment.

Patients experiencing difficulty eating may also benefit from our other integrative care services. A patient who isn’t eating because of depression or anxiety, for example, may be referred to our behavioral health program, where they may receive one-on-one or group counseling. One experiencing difficulty eating because of pain may benefit from pain management services or oncology rehabilitation. A speech therapist may help a patient experiencing difficulty swallowing.

If nutritional support services aren’t available through your cancer treatment facility, and you need someone to personally walk you through dietary recommendations for your personal circumstances, you may search for a RDN independently on the Academy of Nutrition and Dietetics Find a Registered Dietitian Nutritionist online database. 

Some reputable cancer nonprofits also offer nutrition consultations for cancer patients. For example, the Leukemia and Lymphoma Society offers free, one-on-one nutrition consultations to patients and caregivers for all cancer types. Check with nonprofits that are specific to your particular cancer type to see whether they offer similar services.

Many cancer nonprofits also provide nutritional resources and recommendations for coping with specific eating-related side effects. A few you many want to explore include:

How family and friends can help

Family and friends often want to be involved in their loved one’s care but may not know how to help. Patients themselves may not know what kind of help they need. Here are a few things for your family and friends to keep in mind:

  • Your loved one may be more tired than normal and may not have the energy to do the grocery shopping or to prepare food. This may be a significant adjustment if the patient is the one who usually takes on these tasks. Ask whether that’s something you can help with.
  • The smell of food may make the patient nauseous, or he or she may lose his or her appetite. You may make a healthy meal, but the cancer patient just might not be able to eat it at the moment. Try not to be offended if your loved one chooses a smoothie over what you prepared.
  • You may be understandably concerned if your loved one isn’t eating adequately and is losing weight, but try not to push too much. Most people want to eat; their bodies are just working against them during treatment. Pushing too much may cause additional stress. Try to make meal times calm and relaxing.

Managing nutrition during cancer treatment can be challenging, but it may provide you with some control over how you feel during treatment. It may be beneficial to have a team equipped to approach the different challenges or barriers to getting the nutrition you need, like we do at CTCA. If you don’t have that access, seek out the help you need. Maintaining your weight and nutritional status and staying active is worth the effort to improve your treatment outcome and to prepare for survivorship. 

If you’d like to learn more about how we offer nutritional support during cancer treatment or our integrative approach to cancer care at CTCA, call us or chat online with a member of our team.