Women with early state breast cancer may drastically increase their likelihood of 10-year survival by adopting a healthy lifestyle including a healthy diet and moderate physical exercise, according to a new study by researchers from the Moores Cancer Center at the University of California, San Diego (UCSD).

The study, which is published in the June 10, 2007 issue of the Journal of Clinical Oncology, found that women with breast cancer in the early stage who both used a healthy diet and did physical exercise moderately cut their risk of death from the disease by half.

By definitions used in the study on the effect of diet and exercise on breast cancer risk, a healthy diet consists of at least five servings of fruits and vegetables daily and moderate exercise means 30-minute brisk walking six days a week.

The combination of a healthy diet and physical exercise can even help women with breast cancer who were overweight, said the paper’s first author, John Pierce, Ph.D., director of the Cancer Prevention and Control Program at the Moores UCSD Cancer Center. “The key is that you must do both.”

Early studies have linked high intake of fruits and vegetables to lower risk of breast cancer in women.   One study published in Oct. 2006 in the journal Cancer found that overweight or obese women with breast cancer who did physical exercise increased their survival rate by 30 percent compared to those who were not physically active.   But the apparent benefit was not observed in women who were not overweight or obese.   The research was conducted by researchers from the University of North Carolina in Chapel Hill. N.C.

Likewise, an association between moderate physical exercise and reduced breast cancer risk has also been reported early.   For example, moderate exercise for three to five hours a week was found associated with a 50% lower risk of women with breast cancer dying from the disease, Harvard Medical School researchers reported in 2005.

The current study, which is believed to be the first, meant to reveal the combinational effect of diet and physical exercise on women with breast cancer.

In the study, Dr. Pierce and colleagues followed up 1,490 women aged 70 years and younger (average 50 years) with early stage breast cancer for an average 6.7 years to see how diet and physical exercise would affect their survival rates.

The women were randomly assigned to the non-intensive dietary arm of the ongoing Women’s Health Eating and Living (WHEL) study, which is a multi-center study, based at UCSD, investigating the effect of a plant-based diet on additional breast cancer events.

Early stage breast cancer was diagnosed in these women between 1991 and 2000.   The patients had been subject to primary therapy before entering the study.   They were not advised what they should eat or how they should exercise.   Instead, participants were surveyed for their dietary patterns and intensity of physical activity at enrollment and between five and 11 years.

Among the women with early stage breast cancer, those who were obese were less likely to follow a healthy diet and physical exercise than those who were not obese, 16 percent versus 30 percent, the researchers reported.

Seven percent of women who were both physically active and had a healthy diet died from breast cancer during the follow-up, compared to 14 percent among those who only did physical exercise or followed a healthy diet.

“Of particular importance is that this halving of risk was seen in women who were not obese as well as in those who were obese,” said Cheryl Rock, Ph.D., R.D., co-author of the study, of the Center’s Cancer Prevention and Control Program.

“Also, the effect was not seen in women who practiced only one of the lifestyle patterns – high vegetable and fruit intake, or physical activity,” she added.

Because the study was observational, the researchers hope to conduct a trial to investigate exactly how much a healthy diet and or physical exercise would affect the survival rate among women with breast cancer.

The study did not tell what roles other dietary elements such as dietary fat play in the risk of breast cancer.   Earlier studies have found that some dietary patterns may increase risk of breast cancer in women.   For instance, a study published in April 2007 by Anne C. M. Thiébaut and colleagues from the National Cancer Institute in Bethesda, MD showed that diet with high fat increases risk of breast cancer in postmenopausal women.

A scientist affiliated with foodconsumer.org cautions that women who are concerned about their breast cancer risk or those who have already developed the disease should consider not only high intake of fruits and vegetables, but also low intake of animal fat and protein, which would have a significant impact on the breast cancer risk and mortality of the disease, according to Dr. T. Colin Campbell, a distinguished nutrition professor, now retired from Cornel University.