As of Wednesday, July 3, 2013
DEAR DOCTOR K: I’m a cancer survivor. Should I be following special guidelines for diet and exercise?
DEAR READER: Advances in cancer treatment and earlier detection are allowing more people to live longer after a cancer diagnosis. Today, more than 12 million Americans are cancer survivors. And many of them look to diet and exercise to help prevent cancer recurrence, live longer or just feel better.
Recently, the American Cancer Society (ACS) reviewed and summarized the scientific evidence about the role of diet and exercise for cancer survivors. They found that the same things that prevent cancer from developing in the first place also help keep it from coming back. The ACS published its findings in a report called “Nutrition and Physical Activity Guidelines for Cancer Survivors.”
The ACS found that to reduce the chance of cancer returning and increase the chance of surviving, cancer-free, after a cancer diagnosis, survivors should:
— Achieve and maintain a healthy weight;
— Get enough physical activity (at least 150 minutes per week);
— Eat a healthy diet that emphasizes vegetables, fruits and whole grains;
The ACS also provided specific advice for survivors of a variety of major cancers. I’ve put a summary of the guidelines on my website, AskDoctorK.com.
The ACS also advised:
— Cancer survivors should work with a registered dietitian who has special certification in cancer care. He or she can provide specific, evidence-based advice.
— Many cancer survivors have trouble taking in enough calories each day. Eating smaller and more frequent meals can help. Or try special fortified or nutrient-dense foods.
— Use dietary supplements cautiously. Taking more than the recommended daily amounts (RDA) of vitamins and minerals does not improve treatment outcomes or long-term survival. In fact, it can interfere with some cancer treatments. For example, taking a beta-carotene supplement may encourage the growth of lung cancer.
— Exercise can help fight fatigue, keep you functioning and improve your quality of life. Discuss when to start exercising, and how much, with your doctor.
— Obesity appears to increase the risk of breast (and possibly other) cancer recurrence. Losing weight and keeping it off can help improve survival.
When some of my patients hear advice like the ACS has given, they are skeptical. To them, cancer is a powerful force, and it seems unlikely that a healthy lifestyle could do much to tame it. I tell them that the advice is supported by large and well-done scientific studies. There is little doubt from those studies, for example, that survivors of breast cancer who are overweight have a worse prognosis than those of normal weight. Or that those who exercise regularly have a better prognosis than those who don’t.
We even are beginning to understand why. A research study was published recently which showed regular exercise leads to hormonal changes that discourage the growth of breast cancer cells. It’s not anecdotal: It’s science.
Dr. Anthony L. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.