Nutrition and physical activity guidelines for cancer survivors

This article outlines current guidelines regarding nutrition and physical activity for cancer survivors.

A cancer survivor is anyone diagnosed with cancer (cured or currently undergoing treatment). Environmental and dietary factors play a major role in cancer development. Adequate nutrition and regular physical activity improve quality of life and may help increase overall survival.

Guidelines for nutrition and physical activity take into account the status of the disease. For patients currently undergoing chemotherapy or other treatments, the authors recommend limiting dietary supplements (such as multi-vitamins) because they may interfere with some cancer drugs. One example of such an interaction is taking Folic acid (Folate) supplements when treated with anti-folate medications (i.e. Methotrexate). During cancer treatment, physical activity is not harmful, but should be done in moderation. After treatment, lifestyle changes for cancer survivors generally mirror those recommended to the general population.

Body weight should be kept at a healthy level, with a body-mass index (BMI) between 18.5 and 25. Some patients may benefit from weight gain, while others should try to lose weight. Overweight patients still benefit from small losses of 5-10% of body weight even if BMI targets are not met.

Physical activity has been linked to lower risks of recurrence and mortality. Aerobic and resistance training are recommended to improve cardiovascular fitness and muscle strength. Patients should seek medical advice before intense physical activity. Some conditions require special precautions: anemia, severe fatigue, having a compromised immune system, peripheral neuropathy. Patients who just underwent radiation therapy should avoid chlorine exposure (from pools) to irradiated skin. The presence of catheters to administer medication also requires special protection to prevent infection.

Cancer survivors should engage in moderate aerobic physical activity (such as brisk walking) for at least 150 minutes/week. Each session should last more than 10 minutes. Despite the benefits, most cancer survivors do not engage in physical activity.

Colorectal cancer survivors should aim to maintain a healthy weight and to be physically active. Diets rich in fruits, vegetables, poultry and fish are not associated with an increase in cancer recurrence rates compared to Western diets. Current data suggests vitamin D supplementation may influence colorectal cancer outcomes but further research is needed to precisely determine the benefits.

Preventing polyp growth may also lower colorectal cancer risk. However, trials assessing antioxidant vitamins, fiber or folate supplements have not shown benefit in preventing polyps. 

Vegetarian diets which also include fish or dairy products are recommended over strictly vegan diets which often require supplements. Most carbohydrates should come from vegetables, fruits, whole grains and legumes. Nutritional supplements (i.e. multivitamins) do not offer significant benefits for cancer survivors. Vitamins and minerals should primarily be obtained from food sources. Alcohol may increase the liver toxicity of some chemotherapy agents and cause gastrointestinal irritation after radiation treatments. Special attention should be paid to food safety, since many cancer survivors have weaker immune systems to fight food borne infections.

Diet and lifestyle changes should be made after talking to your doctor who may recommend a dietician to help build a meal plan. It is important to be skeptical about news reports or single studies claiming extraordinary benefits of certain products. It is advisable to gather as much information as possible and talk to your doctor before making radical lifestyle changes.