Achieving adequate nutritional support is difficult during cancer therapy or treatment. However, preservation of body composition and proper nutrition will help to maintain strength and may improve daily function and ability to cope with cancer therapies. Adequate nutrition may contribute to a patient feeling better and stronger and may help to fight off infection.
Malnutrition is a primary concern and is an important cause of illness in cancer patients due to difficulty consuming enough calories and nutrients. Protein-energy malnutrition (or protein-calorie malnutrition) is particularly problematic, which is the most common secondary illness in cancer patients. It occurs when a lack of protein and energy (calories) are consumed to sustain the body composition, instigating weight loss. When body stores are severely compromised, the body's functionality declines, which may lead to illness and perhaps death. Exhaustion, weakness, decreased resistance to infection, progress wasting, and difficulties tolerating cancer therapies may result from inadequate nutrition.
People with cancer commonly experience anorexia, which is characterized by a loss of appetite. Anorexia is the most predominate cause of malnutrition and deterioration in patients with cancer. Another common problem in cancer is weight loss and cachexia. Cachexia is a condition where the bodyweight wastes away, characterized by a constant loss of weight, muscle, and fat. It is known as a wasting syndrome and can occur in individuals who consume enough food, but due to disease complications, cannot absorb enough nutrients. Malnutrition, anorexia, and cachexia are serious in cancer patients and can lead to death.
There are many reasons for malnutrition in cancer patients, including the effect of the tumor, effect of treatment, or psychological issues such as depression. The growth of tumors in the digestive system may induce blockage, lead to nausea and vomiting, or cause poor digestion or absorption of nutrients.
Cancer therapies and their side effects may also lead to nutrition difficulties. For example, following surgery, malabsorption of protein and fat may occur. In addition, there may be an increased requirement for energy due to infection or fever.
Cancer patients should maintain an adequate intake of fluids, energy, and protein. The patient's nutrient requirements can be calculated by a dietitian or doctor because requirements vary considerably from patient to patient.
Enteral nutrition may be administered through a nose tube (or surgically placed tubes) for patients with eating difficulties due to upper gastrointestinal blockage such as difficulty swallowing, esophageal narrowing, tumor, stomach weakness, paralysis, or other conditions that preclude normal food intake. If the gastrointestinal tract is working and will not be affected by the cancer treatments, then enteral support is preferable. Parenteral nutrition (most often an infusion into a vein) can be used if the gut is not functioning properly or due to other reasons that prevent enteral feeding.
Nutritional problems related to side effects should be addressed to ensure adequate nutrition and prevent weight loss. The following suggestions will provide some helpful hints on dealing with side effects such as loss of appetite, nausea, vomiting, fatigue, and taste alteration. To deal with appetite loss and weight loss:
- Eat more when feeling the hungriest.
- Eat foods that are enjoyed the most.
- Eat several small meals and snacks instead of three large meals.
- Have ready-to-eat snacks on hand such as cheese and crackers, granola bars, muffins, nuts and seeds, canned puddings, ice cream, yogurt, and hard boiled eggs.
- Eat high-calorie foods and high-protein foods.
- Begin with small portions during a meal to enjoy the satisfaction of finishing a meal. Have additional servings if still hungry.
- Eat in a pleasant atmosphere with family and friends if desired.
- Make sure to consume at least 8-10 glasses of water per day to maintain fluid balance.
- Consider commercial liquid meal replacements such as Ensure.
- Discuss with a physician the possibility of using appetite-increasing medications such Megace or Marinol.
Nausea is a common side effect of several cancer treatments including surgery, chemotherapy, biological therapy, and radiation. If nausea is problematic, the following methods may provide relief:
- Avoid fatty, fried, spicy, greasy, or hot foods with a strong odor.
- Eat small meals frequently but slowly.
- If nausea is particularly worse in the morning, consume dry toast or crackers before getting up.
- Try consuming such foods as clear liquids, toast, crackers, yogurt, sherbet, pretzels, oatmeal, skinned chicken (baked or broiled), angel food cake, and fruits and vegetables that are soft or bland.
- Drink beverages cool or chilled.
- Hot foods may add to nausea, so consume foods at room temperature or cooler.
- Drink or sip liquids (a straw may help) throughout the day, but not during meals. Try sucking on ice chips.
- Discuss with a physician the possibility of using antinausea medications (also called antiemetics) such Zofran or Kytril.
Vomiting may occur for several reasons due to the cancer itself, treatment, or emotional upset. If vomiting occurs, the following guidelines may help:
- Do not drink or eat until vomiting has subsided, then consume small amounts of clear liquids.
- When able to tolerate clear liquids, try to consume a full liquid diet (including dairy products unless they are difficult to digest). Begin with small quantities and gradually return to a regular diet if nausea and vomiting have dissipated.
If fatigue is preventing receiving adequate nutrition, the following strategies may help:
- Try using frozen, canned, or ready-to-use foods.
- Eat high-calorie foods.
- Have ready-to-eat snacks on hand such as cheese and crackers, granola bars, muffins, nuts and seeds, canned puddings, ice cream, yogurt, and hard-boiled eggs.
- Consider using a service such as Meals on Wheels, a delivery or home care service.
- Invite friends or family over to assist with meal preparation.
- Consider commercial liquid meal replacements such as Ensure.
Taste changes can give foods a metallic or off flavor. Consider the following strategies to alleviate taste changes.
- If meats have a metallic taste, try other sources of protein such as dairy products, poultry, fish, seafood, peanut butter, eggs, seeds, nuts, tofu, and legumes.
- Use plastic utensils to decrease metallic flavor.
- Choose tart foods such as citrus juices, lemonade, cranberry juice, and pickles to help alleviate a metallic taste. If sore mouth and throat symptoms are also present, do not consume these foods.
- Consume a variety of foods.
- Try different seasonings, herbs, and sauces.
- Choose foods that look and smell good.
- Dilute drinks that are too strong or sweet with water.
- Rinse mouth often with baking soda and water.
Alternative and complementary therapies
There is no alternative or complementary nutritional therapy that has proven effective for cancer prevention or cancer treatment. However, the are several foods and nutraceuticals such as garlic, plant sterols, green and black tea polyphenols, and soybean products (soy isoflavones) that have shown promise in previous research for anticarcinogenic properties. Many of these products are actively being tested in clinical trials to elucidate anti-carcinogenic properties. As for prevention, past research has clearly demonstrated that intake of fruits and vegetables are correlated to a lower incidence rate for certain types of cancer. It is important to check with a dietitian or doctor before taking nutritional supplements or alternative therapies because they may interfere with cancer medications or treatments.
Keane, Maureen, et al. What to Eat If You Have Cancer: A Guide to Adding Nutritional Therapy to Your Treatment Plan. Lincolnwood, IL: National Textbook Company/Contemporary Publishing Group, 1996.
Quillin, Patrick, and Noreen Quillin. Beating Cancer With Nutrition—Revised. Sun Lakes, AZ: Bookworld Services, 2001.
Singletary, Keith. "Diet, Natural Products and Cancer Chemo-prevention." The Journal of Nutrition (2000): 465S-466S.
Alberts, D.S., et al. "Lack of Effect of a High-Fiber Cereal Supplement on the Recurrence of Colorectal Adenomas." New England Journal of Medicine (2000): 1156-62.
Schatzkin, A., et al. "Lack of Effect of a Low-Fat, High-Fiber Diet on the Recurrence of Colorectal Adenomas." New England Journal of Medicine (2000): 1146-55.
National Center for Complementary and Alternative Medicine (NCCAM), 31 Center Dr., Room #5B-58, Bethesda, MD 20892-2182. 800-NIH-NCAM. Fax 301-495-4957. <http://nccam.nih.gov>.
The National Cancer Institute (NCI). Public Inquiries Office, Building 31, Room 10A31, 31 Center Drive, MSC 2580, Betheseda, MD 20892-2580. 301-435-3848, 800-4-CANCER. <http://cancer.gov/publications/>.<http://cancertrials.nci.nih.gov>.<http://cancernet.nci.nih.gov>.
Crystal Heather Kaczkowski, MSc.
—A condition where weight loss is due to a loss of appetite or lack of desire to eat.
—A condition in which the bodyweight "wastes" away, characterized by a constant loss of weight, muscle, and fat.
—A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body.
—Feedings administered through a nose tube (or surgically placed tubes) for patients with eating difficulties.
—Also called a functional food. These food products have other health promoting or disease preventing properties over and above their use as a food product. Specifically, a nutraceutical or functional food is a food for which a health claim has been authorized.
—Feeding administered most often by an infusion into a vein. It can be used if the gut is not functioning properly or due to other reasons that prevent normal or enteral feeding.
Protein-energy (or protein-calorie) malnutrition
— Not enough of protein and energy are consumed to sustain the body composition, resulting in weight loss and possibly death.
QUESTIONS TO ASK THE DOCTOR
- What effect will the treatment or disease have on my body nutritionally (i.e., on the ability to eat, digest food, absorb nutrients, energy requirements)?
- How long will the negative side effects last?
- Is there a risk of malnutrition or weight loss with this type of cancer or treatment?
- What nutrients are most important to obtain during treatment?
- Are there any nutritional supplements that may be required?