Radiation therapy uses high-energy rays to destroy cancer cells, but this process can temporarily affect healthy tissues. Maintaining proper nutrition during this period is a major factor in supporting the body through treatment and recovery. The primary nutritional goal is to provide the resources needed to repair cellular damage, maintain physical strength, and support the immune system. Adjusting the diet helps patients maintain their weight and energy levels while managing common side effects.
Foundational Nutritional Goals During Treatment
The body requires increased nutritional support during radiation therapy to withstand physical stress and promote healing. The two most important components of the diet are high protein intake and sufficient caloric density. These macronutrients counteract the muscle wasting and fatigue that can occur during high cellular repair.
Protein provides the amino acids necessary to repair tissues damaged by radiation and maintain lean muscle mass. Cancer patients often need a higher protein intake than average, typically ranging from 1.1 to 1.3 grams per kilogram of body weight per day. Incorporating protein into every meal and snack ensures a steady supply for the body’s increased demands.
Adequate calorie intake is equally important to prevent unintentional weight loss, which can decrease treatment tolerance. Caloric needs are estimated at 28 to 31 calories per kilogram of weight daily to provide energy for tissue health and regrowth. Healthy fats, such as those found in olive oil, avocados, and nuts, are calorie-dense and boost the energy content of meals without adding excessive volume.
Unsaturated fats also contain anti-inflammatory properties that support immune function, which is often compromised during treatment. Carbohydrates from sources like fruits, vegetables, and grains provide the body’s main source of energy, helping to combat fatigue. Focusing on these foundational nutrients helps the patient maintain strength and avoid treatment interruptions.
Dietary Strategies for Managing Common Side Effects
Managing the side effects of radiation therapy is often accomplished by adjusting the texture, temperature, and flavor of foods. The area receiving radiation dictates which side effects occur, requiring specific dietary modifications. This tailored approach helps patients maintain adequate intake, which is necessary for recovery.
Managing Taste Changes and Dry Mouth
Radiation targeting the head and neck can damage the salivary glands and taste buds, leading to dry mouth and altered taste perception. Taste changes may manifest as a metallic, bitter, or overly sweet sensation, or a complete loss of flavor. To manage dry mouth, patients should frequently sip liquids and use sugar-free hard candies or gum to stimulate saliva production.
Foods should be moistened with extra sauces, gravies, broth, or yogurt to make them easier to chew and swallow. Using plastic utensils can help mitigate a metallic taste. If food tastes bland, adding strong flavors like herbs, mild spices, lemon juice (if the mouth is not sore), or small amounts of maple syrup can make meals more appealing.
Cold foods, such as sherbet, frozen fruit, and ice pops, can be soothing for a sensitive mouth and often have less intense odors and flavors. Rinsing the mouth with a solution of baking soda and salt water before meals can help neutralize lingering bad tastes and maintain oral hygiene.
Dealing with Nausea and Vomiting
Nausea is a common side effect, particularly when radiation is directed at the abdomen or pelvic area. Dietary management focuses on consuming bland, low-fat foods that are easy to digest. Examples include:
- Dry toast
- Crackers
- Pretzels
- Plain yogurt
- Clear broths
Eating small, frequent meals helps prevent the stomach from becoming too full or too empty, which can worsen nausea. It is recommended to drink liquids at least 30 minutes before or after meals, not with them, to avoid feeling overly full. Sour flavors, such as lemon drops or ginger ale, may help settle the stomach.
Foods should be eaten at room temperature or cooler to minimize strong odors that can trigger nausea. Patients should avoid fried, greasy, spicy, or excessively sweet foods, as these are harder to digest and can exacerbate symptoms. Resting in an upright position for at least an hour after eating can also help reduce the likelihood of vomiting.
Coping with Sore Throat or Difficulty Swallowing (Dysphagia)
Radiation to the head, neck, or chest can cause inflammation and pain, leading to a sore throat or difficulty swallowing (dysphagia). The strategy is to modify the texture of foods to make swallowing less painful. Soft, moist foods are the best choices, including soft-cooked eggs, mashed potatoes, pureed soups, and cooked cereals.
Moistening solid foods with gravy, sauce, butter, or milk increases their slipperiness and ease of passage. If pain is severe, a liquid or pureed diet may be necessary, consisting of high-calorie, high-protein liquid supplements, milkshakes, and smoothies. Cool (but not frozen) foods like yogurt, custard, and sherbet can provide a soothing effect on an irritated throat.
It is helpful to take prescribed pain medication about 30 to 60 minutes before a meal to maximize comfort during eating. Patients should avoid dry, crunchy, or rough-textured foods, such as chips, crackers, and raw vegetables, which can scratch or irritate the sensitive lining of the throat.
Addressing Diarrhea or Constipation
Radiation to the abdomen or pelvis can irritate the bowel lining, leading to changes in bowel movements. Diarrhea is managed by temporarily shifting to a low-fiber diet that includes foods high in soluble fiber, which helps firm up stools. Good sources of soluble fiber include:
- Bananas
- Applesauce
- White rice
- Peeled potatoes
- Oatmeal
It is important to avoid foods high in insoluble fiber, such as raw vegetables, whole grains, and nuts, which can speed up bowel movements. Hydration is paramount during diarrhea to replace lost fluids and electrolytes, using options like clear broths, sports drinks, and juices. Patients should also limit alcohol, caffeine, and foods containing sugar alcohols like sorbitol, as these can worsen diarrhea.
Constipation, while less common, requires increasing fluid intake and gradually introducing gentle sources of fiber. Adequate hydration, aiming for 8 to 10 cups of fluid daily, helps soften stools. Gentle exercise, such as walking, can also encourage healthy bowel function.
Foods and Practices to Limit or Avoid
During radiation treatment, certain foods and practices should be avoided to minimize irritation to sensitive tissues and reduce the risk of infection when the immune system is lowered. This includes foods that physically exacerbate symptoms and those that pose a food safety hazard.
Irritating Foods
Acidic or spicy foods can severely irritate the mucous membranes of the mouth, throat, and digestive tract, especially if the radiation target is in those areas. Common offenders include citrus fruits and juices, tomatoes and tomato-based products, and anything seasoned with chili powder, hot sauce, or pepper. Limiting these items helps prevent pain and inflammation.
Foods with rough, sharp, or crunchy textures should also be avoided because they can scratch a sore mouth or throat. This includes raw vegetables, chips, pretzels, and crusty bread. Alcohol and caffeinated beverages can contribute to dry mouth and irritation and should be limited or avoided during treatment.
Food Safety (Immunocompromised Diet)
Radiation therapy can lead to a temporarily compromised immune system, making the patient more susceptible to foodborne illnesses. Strict food safety practices are necessary to prevent infection. Patients should avoid all raw or undercooked animal products, including:
- Meat
- Poultry
- Fish
- Eggs
This means thoroughly cooking all meats to a safe internal temperature and ensuring egg yolks are firm. Unpasteurized dairy products, raw sprouts, and unwashed produce are considered high-risk foods and should be avoided. Kitchen hygiene is paramount, requiring frequent handwashing, using separate cutting boards for raw and cooked foods, and ensuring surfaces are clean to prevent cross-contamination.
Perishable foods should be refrigerated promptly, and leftovers must be reheated to 165°F to kill potential bacteria. These safety measures should be maintained during treatment and until the immune system has recovered.