Most people know that eating a diet rich in fruits, vegetables, low-fat dairy, and whole grains and restricting consumption of unhealthy fats and red meat can help prevent chronic illness, yet few people eat accordingly. Studies have also shown that diet and exercise help prevent breast cancer, yet obesity rates in women continue to rise. New information suggests women with early stage breast cancer can prolong their lives by following a prudent diet. Will they get the message?Eat Plants, Live Longer
Kathy Allen, MA, RD, LD/N, CSO, is a registered dietician with board certification as a specialist in oncology nutrition. She is also manager of nutrition therapy at Moffitt Cancer Center in Tampa, FL. She noted that eating a diet high in fruits and vegetables and low in animal protein appears to reduce the risk of breast cancer. This is because a plant-based diet is naturally rich in phytochemicals, compounds believed to help ward off cancer. Ms. Allen said studies show that people who consume these cancer-fighting foods have a lower incidence of cancer, including breast malignancies.
John P. Pierce, PhD, Sam M. Walton Professor for Cancer Prevention and director of Cancer Prevention and Control at University California San Diego (UCSD) School of Medicine and USCD Moores Cancer Center, believes advances in breast cancer diagnosis and treatment partially account for the growing role diet plays in cancer survival. Breast cancer has evolved from a fatal disease to a chronic one, Dr. Pierce explained, and patients often survive 20 years or more after a breast cancer diagnosis. Many patients with cancer are dying from causes unrelated to the disease, like diabetes or heart disease. As a result, the benefits of maintaining a healthy diet and exercising regularly are increasingly evident.The Estrogen Factor
The Women’s Healthy Eating and Living (WHEL) trial followed the eating habits of more than 3,000 survivors of early stage breast cancer to determine whether a healthy diet reduced their risk of recurrence. In 2007, researchers concluded that, overall, eating a diet consisting largely of fruits, vegetables, and fiber did not reduce the likelihood that their cancer would return.
Researchers conducted a secondary analysis in 2008 that looked at a subgroup of women who did not experience hot flashes. Those who ate a prudent diet were 31% less likely to experience cancer recurrence. Investigators hypothesized that the diet reduced estrogen levels, thereby reducing cancer risk.
Dr. Pierce, the principal investigator of the WHEL study said, “Women who have hot flashes are having them because their hormone levels are low.” Women with higher levels of estrogen do not experience hot flashes. Estrogen is associated with tumor development in some patients, which is the reason many breast cancer treatments involve inhibiting estrogen. In other words, where breast cancer risk and recurrence are concerned, having hot flashes may be a positive sign.
In an earlier statement about the study’s findings, Dr. Pierce noted that some women are genetically resistant to endocrine therapy, and he said it was possible they were the ones who benefited most from eating a prudent diet. His research team is proceeding with studies to determine why and how the diet appears to lower recurrence risk in some women and not in others.A Weighty Issue
Ms. Allen listed excess weight as another concern for women with cancer. “We have suspected for years that lifestyle was an important factor in the incidence of many types of cancer, but more recently, there have been studies that have borne that out,” Ms. Allen said. Recent data demonstrate that women who maintain a healthy body mass index are less likely to develop breast cancer, she added.
Silvia Herszkopf, RD, CDN, an ambulatory oncology nutritionist at the Montefiore-Einstein Cancer Center, said many women with breast cancer that she counsels are overweight. In addition, many are postmenopausal. After menopause, a woman’s metabolism slows, making it difficult to shed extra pounds and easy to gain them. Ms. Herszkopf said diet is not enough, and exercise needs to be part of any weight loss program. “If you decrease your calorie intake, your metabolism slows down,” she explained. “But, by increasing your physical activity, you’re helping to increase your metabolism.”
Exercise has other protective benefits for postmenopausal women with breast cancer. Bone loss is a frequent complication of many breast cancer treatments. A proper exercise routine that includes load-bearing or strength-training exercises can help women maintain bone mineral density, staving off osteoporosis. Women with cancer should speak with their physician before beginning an exercise program. Some exercises could be harmful to women whose bone mineral density is already compromised.Eating for Life