Scripps Cancer Center

Antioxidants During Radiation Treatment

Medical Nutrition Therapy

 

About

Antioxidants are an important part of a balanced diet but taking antioxidant dietary supplements during radiation could negatively impact treatment. Speak with your healthcare team and let them know what vitamins, minerals, and herbal supplements you are currently taking.

Understanding Antioxidants

Antioxidants can be endogenous, meaning made by the body, or exogenous, meaning externally added to the body such as by foods or dietary supplements. Oxidative stress can damage the body and lead to illness and aging. Antioxidants can decrease the oxidation of free radicals, which in turn can prevent, lessen, or improve damage to the body’s cells, whereby protecting the body.

Antioxidants can decrease risk of many chronic diseases, including some types of cancer. But taking high doses of antioxidants, specifically from dietary supplements, can decrease the benefits of radiation treatment. Why? Radiation is used to purposefully damage the cancer cells and antioxidants may help protect the cancer cells from that damage. During radiation treatment, it is recommended to avoid antioxidant supplements.    

Multivitamin Supplements

Multivitamins are a combination of many vitamins and minerals. Therefore, antioxidants present (such as vitamin C) will be in a lower quantity than a “single agent” vitamin supplement that contains only one vitamin or mineral. This is safer to consume during radiation than a single-agent supplement. Speak with your healthcare team to learn what is recommended for you.

Antioxidants in the Diet

Foods high in antioxidants are safe to consume during radiation treatment but be sure to consume typical serving sizes and spread these foods throughout the day instead of eating an excessive portion size in one sitting. Serving sizes of common antioxidant-rich foods are:

  • Fruit, whole: 1 piece

  • Fruits or vegetables, chopped: 1 cup

  • Fruits or vegetables, cooked: ½ cup

Beverages, such as shakes, smoothies, and oral nutrition supplements (i.e., Boost, Ensure, Kate Farms) with antioxidants are safe to include in the diet. These may contain antioxidants but have amounts much less than is found in dietary supplements, such as pills and powders. Speak with a Registered Dietitian Nutritionist to determine which oral nutrition supplement is best for you. If consuming more than one oral nutrition supplement a day, spread them out so only consuming one drink in one sitting and do not take a multivitamin. If making a smoothie at home or purchasing one outside of the home, do not add powders that contain large amounts of antioxidants.

 

 

Note: Results from randomized control trials examining the use of dietary supplements have not yet supported claims such as curing or preventing cancer. It is best to obtain antioxidants from a well-rounded diet with a plant-based, food first approach. While undergoing radiation treatment, whole foods and oral nutrition supplements are safe to consume, but antioxidant single-agent supplements should be avoided.