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More Fruits, Vegetables Don't Stop Breast Cancer

CancerWise - October 2007

Following a low-fat, high-fiber diet that's nearly double the normally recommended five servings a day of fruit and vegetables does not lower women's risk of breast cancer recurrence or increase their chances for survival, according to a new report.

Significance of research

The findings, published in the July 18 issue of the Journal of the American Medical Association, are a result of the Women's Healthy Eating Living (WHEL) clinical trial, the largest and most comprehensive diet prevention study ever conducted.

"The WHEL's findings are pivotal because we always assumed that we were not eating enough fruits and vegetables and that the more we ate the more protected we would be against cancer," says Lovell Jones, Ph.D., director of the Center for Research on Minority Health in M. D. Anderson's Department of Health Disparities Research and principal investigator on the study at M. D. Anderson.

What the study did not account for, however, is what the participants were eating prior to their enrollment in the study, be it healthy or not. Jones believes that for the greatest preventative effect, women must make healthy changes to their diet long before a possible diagnosis of breast or any other type of cancer.

Research methods

WHEL enrolled 3,088 women who had been treated for early-stage breast cancer at seven institutions across the country. M. D. Anderson enlisted 380 breast cancer survivors, including 50% (50 women) of the African-American women who participated nationwide.

Women between the ages of 18 and 70 were chosen randomly from 1995 to 2000 and followed for seven years.

The intervention group included 1,537 women who:

  • Ate an average of nine daily servings of fruits and vegetables
  • Followed a diet high in fiber and low in fat
  • Received intense monitoring
  • Received frequent phone counseling sessions
  • Were offered 12 cooking classes the first year
  • Received monthly health newsletters

The comparison group included 1,551 women who:

  • Ate five daily servings of fruits and vegetables
  • Ate an overall healthy diet
  • Received written material about a healthy lifestyle
  • Were offered four cooking classes the first year
  • Received bimonthly health newsletters

Primary results

Researchers were surprised that there were no statistical differences between the groups.

Of the 3,088 participants, 518 had a breast cancer recurrence or a second primary cancer:

  • 256 (16.7%) from the intervention group
  • 269 (16.9%) from the comparison group

The 315 women who died from the disease included:

  • 155 (10.1%) from the intervention group
  • 160 (10.3%) from the comparison group

Background

Earlier observational studies of the WHEL's own control group saw a 40% increase in survival, Jones says. Additionally, a report of interim analysis from the Women's Intervention Nutrition Study found that a low-fat diet might reduce the risk of recurrence.

"Given these findings, we really did think that we would see a significant statistical difference in the recurrence and survival rates between the women who adopted a super healthy lifestyle compared to those who ate the recommended allowance."

What's next?

Future studies examining the outcomes of the trial's minority participants are planned.

– From staff reports

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© 2014 The University of Texas MD Anderson Cancer Center