By Erin Dummert RD, CD

Nutrition plays a critical role in cancer prevention and treatment. However, it is important to remember that prevention and treatment are 2 distinct phases. What works for one does not necessarily work for the other. In this article, we will explore the role of nutrition in both cancer prevention and cancer treatment; and compare the nutrition recommendations for each phase.

Good Nutrition Safeguards Your Health

According to the American Institute for Cancer Research (AICR), 30 to 40 percent of all cancers are directly linked to diet and exercise. This means that the foods you eat make a big impact on your long term health and longevity. It has been said that disease is not caused by what we eat, but by what we do not eat. In essence, it is not the occasional high fat snack or even frequent fast food dining that causes cancer. It is the fact that we do not eat enough of the beneficial plant foods needed to fight disease and keep our immune systems strong.

Nutrition Can Help Prevent Cancer

Proper nutrition helps prevent cancer by:

• Protecting cells from damage
• Enhancing immunity
• Changing estrogen metabolism
• Improving communication among cells
• Detoxifying carcinogens
• Repairing cell damage.

There are thousands of plant chemicals in foods that can help prevent cancer and other diseases. This is the basis for the United States Department of Agriculture's recommendation of a minimum of 5 servings of fruit and vegetables daily for good health. For cancer prevention, fruit and vegetable intake should meet or exceed 9 servings per day. Despite this advice, less than 20 percent of Americans consume 5 servings daily, and even fewer reach 9. In addition to fruits and vegetables, other foods such as whole grains, tea, flaxseed, and soybeans are beneficial in reducing cancer risk.

AICR cites the following recommendations for cancer prevention:

• Choose a diet rich in a variety of plant-based foods
• Eat plenty of vegetables and fruits
• Maintain a healthy weight and be physically active
• Drink alcohol only in moderation, if at all
• Select foods low in fat and salt
• Prepare and store foods safely
• Do not use tobacco in any form.

Good Nutrition Cannot Cure Cancer

Oftentimes, cancer patients turn to guidelines for cancer prevention to help fight their disease. Unfortunately, good nutrition will not cure cancer. Just as quitting smoking will not cure lung cancer after its been diagnosed, neither will taking an antioxidant supplement or even eating 9 servings of fruits and vegetables daily. If possible, cancer patients should strive to follow the AICR recommendations for cancer prevention during treatment. However, once cancer develops, the role of nutrition changes to focus on supporting and managing the side effects of treatment.

Supporting Cancer Treatment with Nutrition

Whether cancer is treated with surgery, chemotherapy, or radiation therapy, proper nutrition can have a profound impact on the success of the treatment. The goals of nutrition in cancer treatment are to:

• Maintain body muscle and prevent weight loss
• Prevent nutrient deficiencies
• Minimize the side effects of treatment
• Promote the healing and building of healthy cells
• Support the immune system.

Reaching these goals through proper nutrition can improve the quality of life of patients receiving treatment, decrease hospitalizations, and prevent delays in treatment. Common nutrition recommendations during cancer treatment are to:

• Eat enough calories to maintain your usual weight
• Drink 8-10 glasses of water or non-caffeinated beverage daily
• Eat 4-5 servings of high quality protein daily
• Eat as many fruits, vegetables, and whole grains as possible.

For more information on nutrition during chemotherapy see the following article from TheDietChannel: Chemotherapy: Foods to Eat During Treatment.

Beware of Antioxidants during Cancer Treatment

A great deal of scientific information supports the role of antioxidants in cancer prevention. The AICR states, "Considerable laboratory evidence from chemical, cell culture, and animal studies indicates that antioxidants may slow or possibly prevent the development of cancer." However, large amounts of antioxidants may actually work against the treatment and decrease its effectiveness. For this reason, it is important that cancer patients discuss any supplements and nutritional intake with their health care team.

Cancer Survivors

After cancer treatment, nutrition again plays the role of prevention, helping to avoid a recurrence of the same cancer or the development of a secondary cancer. While there is less information on secondary cancers, it is widely believed that the same recommendations for prevention of a primary cancer apply. In this stage, it is critical that cancer survivors push the recommendations to the limit and fuel their bodies for health with fruits, vegetables, whole grains, and other plant foods.