Radiation and Diet

Contributors: Barbara Gordon, RDN, LD and Sarah Klemm, RDN, CD, LDN
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About half of people with cancer receive radiation therapy, or radiotherapy. For some patients, radiation is one of many types of cancer treatments. For others, it is the only treatment given.

Radiation treatment shrinks, slows the growth and, over time, kills cancer cells. One side effect, however, is that healthy tissues in the area that receive radiation also may be destroyed. An important goal during radiation therapy is eating enough to maintain your weight and keep up your strength. You also need to ensure that your body gets the nutrition it needs to promote the regrowth of healthy tissues.

An Added Focus on Healthy Eating

During radiation therapy, it is important to focus on making nutritious choices. In addition, your calorie and protein needs may be higher during treatment.

It is not uncommon for radiation therapy to zap your energy and lessen your appetite. Many patients feel nauseous, which also dampens the desire to eat. Your body needs a certain number of calories to maintain health and may require extra calories to regenerate healthy tissues. 

Carbohydrates and Fats
Aim to get most of the calories you need from healthy carbohydrate-containing foods, including vegetables, fruits, and whole grains. Also select sources of healthful unsaturated fats such as avocados, seeds, fatty fishes, nuts and vegetable oils.

During radiation therapy, you need to get enough protein to keep your immune system working well and support the repair of body tissue. It is not uncommon for patients to need extra protein. A registered dietitian nutritionist might suggest, for example, that you add more milk, cheese and eggs to your daily eating plan. Or, increase your servings of beans, lean meats, fish and poultry.

Vitamins and Minerals
Your body needs vitamins and minerals to help with healing and keeping the immune system strong. These nutrients also help convert food into energy and support tissue repair. An eating style that includes a variety of foods is the best way to ensure you get the vitamins and minerals that your body needs. If you are struggling to eat enough food, you may need to take a vitamin and mineral supplement. Always check with your health care provider before starting any new supplements. Some supplements may interact with your medicines or treatments.

Special Nutritional Concerns
Changes in eating are common during periods of radiotherapy. Radiation treatments are targeted at the specific area of the body where the cancer is located. Which means, recommendations for eating and drinking can vary depending on the specific type of cancer. They may also relate to the side effects of other cancer treatments.

Mouth Sores and Throat Problems
Radiation therapy may irritate the lining of the mouth, throat and gums (mucositis), as well as the lining of the throat (esophagitis). These side effects tend to be more common in patients with head and neck cancers. And, they can make it harder to chew or swallow foods. Choosing foods that are soft and easy to chew may make it easier to get the nutrients you need. Consider moistening foods with sauces and broth and eating cool or room-temperature food. Sucking on ice chips and using a saltwater rinse also may help soothe your mouth. It’s also advisable to avoid alcohol and tobacco products as these can aggravate sores further. 

Radiation to the abdomen area may cause bloating, or swelling of the belly, due to retained fluid or gas. To reduce your risk for bloating during radiation therapy:

  • Monitor your intake of gas-producing foods such as beans, broccoli, cabbage, cauliflower, corn, leafy greens and beans.
  • Avoid sodas, sparkling waters and other carbonated beverages.
  • Limit the use of straws to avoid swallowing excess air when you eat or drink.
  • Select foods lower in dietary fiber.

These are not long-term modifications. Once your symptoms are in check, ask your health care provider how to slowly add these foods back into your eating plan.

Constipation and Diarrhea
People who undergo radiation may experience changes in bowel habits. If the target area of the radiation is in the intestines or colon, it may cause irregular bowel patterns. Plus, pain and nausea medicines can upset digestion and lead to constipation or diarrhea.

Ask your health care provider about the potential reason for your change in bowel habits. Find out if dietary changes might be helpful for you. Depending on your symptoms, you may be advised to increase or decrease your fiber intake. Dietary fiber is found in foods such as whole-grain breads, brown rice, and oatmeal, as well as beans, peas, lentils, vegetables and fruit.

Need Help Eating Well During Radiation Therapy?

A registered dietitian nutritionist can help design an eating plan that meets your special needs, as well as your individual food preferences. The RDN will also help you manage other special nutrition needs. For example, modified eating patterns may be needed to help with other health conditions such as kidney disease, diabetes or high blood pressure.

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