People with cancer are at risk for developing nutritional deficiencies. The deficiencies may be the result of the cancer itself, or the side effects of common cancer treatments such as surgery, chemotherapy, and radiation therapy.
Cancer directly affects your nutritional status by changing the body's metabolism and causing you to lose your appetite. Your body increases energy use, which means you need more calories to maintain your current weight and lean body mass. Cancer-associated loss of appetite is probably the result of physical changes but may also be due to a psychological response to the disease.
Cancer also causes individual changes in the body's ability to break down carbohydrates, protein, and fat. These changes lead to the loss of muscle and fat.
Several things may contribute to the type and degree of nutrient deficiencies:
Where in the body the cancer occurs
How severe the cancer is at the time of your diagnosis
What symptoms you have
The type of cancer treatment, and how often you receive it
Side effects associated with your cancer treatment
How the cancer affects your ability to eat and tolerate food and nutrients
People with cancer frequently require a high-calorie diet to prevent weight loss. They may also need a diet that is high in protein to prevent muscle wasting. Foods that are high in calories and protein include peanut butter, whole milk, milkshakes, meats, and cheeses.
Some individuals with cancer develop an aversion to fats. If this happens, eat high-protein foods with a lower fat content such as low-fat shakes, yogurt, cottage cheese, and lean meats.
For the diet to remain well-balanced, you must eat fruits and vegetables. To increase calories, use more fruit juices or dried fruits rather than whole fruits. Choosing calorie-dense vegetables such as corn and peas will also increase the calories in the diet.
The side effects of common cancer therapies vary by the treatment and the area of the body undergoing treatment. The following are some side effects and helpful suggestions. They do not replace, but rather aid, drugs used to relieve these symptoms.
CHEWING AND SWALLOWING DIFFICULTY
Thick liquids such as milkshakes or semisolid foods like mashed potatoes and gravy may be easier to swallow and are less likely to cause aspiration (inhaling food).
PAIN, NAUSEA, VOMITING, DIARRHEA
Eating a meal immediately before or after the treatment may ease symptoms. Your position while eating may also contribute to symptoms.
TASTE CHANGES AND AVERSIONS
Avoid foods with strong odors.
Eat bland foods. Avoid strong flavors like spices, acidic foods, and sour-tasting foods.
Eat cold foods. Avoid hot or warm foods.
If you are experiencing severe nausea, avoid your favorite foods. Eating a food during severe bouts of nausea may cause you to develop an aversion to it.
BODY WEIGHT LOSS AND MUSCLE WASTING
Add diced meat or cheese to sauces, vegetables, soups, and casseroles.
Add extra eggs or egg whites to foods. Never use raw eggs. They may be contaminated with salmonella, which is dangerous for everyone but especially those who are immune-suppressed. Raw eggs also contain a vitamin binder.
Add powdered milk to foods and beverages.
Consider using commercially available nutritional supplements. Make your own high-calorie shake by adding an instant breakfast drink mix to milk, fruit, cookies, peanut butter, or other favorite mixers.
Drink high-calorie beverages such as juices, milk, or sweetened drinks.
Eat smaller, but more frequent meals.
If you are unable to digest fat, talk to your health care provider about alternative fat sources. Supplements containing medium-chain triglycerides are often recommended for this purpose.
Increase fats in the diet to increase energy consumption, if you are tolerating fats. Add margarine or butter to breads and vegetables. Add gravies and sauces to foods in large amounts.
Increase protein and calories in the diet.
Snack throughout the day on calorie-dense foods such as nuts, hard candy, and dried fruits.
Some cancer patients become unable to digest dairy products, which is called lactose intolerance. Symptoms include bloating, gas, and diarrhea immediately after eating lactose-containing foods.
People with lactose intolerance have trouble digesting the sugar in milk. Lactose intolerance is due to an inability to produce lactase, the enzyme that digests milk. The wall of the gastrointestinal tract produces this enzyme. You can take lactase to help you digest lactose products.
You can also buy lactose-free milk at most grocery stores. Cultured dairy products such as yogurt, cheeses, and buttermilk will contain less lactose, because the active cultures help to digest it.
You may be able to tolerate small amounts of lactose occasionally. Or, you may have to remove lactose entirely from your diet until you have fully recovered from your cancer therapy.
Surgery on the stomach may cause dumping syndrome. If you have dumping syndrome, food is "dumped" into the small intestine 10 or 15 minutes after being swallowed. Ordinarily, food is partially digested in the stomach, then released gradually into the digestive tract.
The presence of undigested food in the intestine leads to:
DeLegge MH. Nutrition in gastrointestinal diseases. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 5.
Jennifer K. Mannheim, ARNP, Medical Staff, Department of Psychiatry and Behavioral Health, Seattle Children's Hospital; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.