Increasing vegetables and fruits doesn't prevent breast cancer recurrence

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http://www.eurekalert.org/pub_releases/2007-07/uoc--iva071207.php

Eating a diet very high in vegetables, fruit and fiber and low in fat

did not reduce breast cancer recurrence or death in early stage breast

cancer survivors, according to a new study. Researchers from the

and s Cancer Center at the University of California,

San Diego found that this intensive diet provided no additional

benefit to following the generally recommended dietary guidelines.

The study is published in the July 18 issue of the Journal of the

American Medical Association.

The results are from the multi-center Women's Healthy Eating and

Living (WHEL) Study, based at UC San Diego, the largest randomized

clinical trial to assess the influence of diet on additional breast

cancer events. Participating institutions included the University of

California, ; Stanford University; Kaiser Permanente in Oakland

and Portland; University of Arizona at Tucson, and the University of

Texas M.D. Cancer Center in Houston.

" This is a definitive study, " said principal investigator Pierce,

Ph.D., director of the University's Cancer Prevention and Control

Program. " The WHEL Study provides strong evidence that, for the

typical woman diagnosed with early stage breast cancer, there is no

additional health benefit over 7 years from dramatically increasing

the diet's amount of nutrient-rich plant-based foods, compared to

following the recommended healthy diet. "

The study followed 3,088 breast cancer survivors, aged 18 to 70, for

between 6 and 11 years. Participants were randomly assigned to one of

two diet groups. The comparison group followed the guidelines promoted

by the U.S. Department of Agriculture (USDA). The intensive

intervention group was asked to follow a daily dietary pattern that

included 5 vegetable servings, 16 ounces of vegetable juice, 3 fruit

servings, 30 grams of fiber, and 15-20% from fat.

At the start of the study, both groups consumed similar amounts of

vegetables and fruits (7 servings a day on average), fiber, and

calories from fat. Telephone counseling helped women assigned to the

intensive dietary group to change their diets substantially: at the

end of the first year of observation, women in the intervention group

had increased their average vegetable and fruit intake by 5 servings

per day (to an average of 12 servings per day). They also increased

their fiber intake substantially and decreased fat intake.

These large changes in self-reported dietary pattern were validated by

large changes in plasma carotenoid concentrations. By the fourth year

of the trial, relative to the comparison group, the intensive dietary

group was still consuming more vegetable servings (+65%), more fruit

servings (+25%), more fiber (+30%), and less fat (-13%). The

difference in diets between the two groups was maintained throughout

the trial.

" The dietary changes achieved and maintained by the women in the

intervention group resulted in some of the biggest differences in

dietary pattern ever reported in a large randomized clinical trial, "

said Vicky Newman, M.S., R.D., Director of Nutrition Services for the

Cancer Prevention Program at the s UCSD Cancer Center. " It

provides further evidence of the effectiveness of telephone counseling

in helping people to change behaviors. "

After a median of 7 years of follow-up, the study observed no

difference in recurrence or survival between groups: about 17% of

women in both diet groups developed a breast cancer recurrence or new

breast cancer, and 10 % of women in both groups died.

" These results do not mean that women should stop paying attention to

what they eat, " said study investigator Bette Caan, Dr.P.H., senior

epidemiologist at the Kaiser Permanente Division of Research in

Oakland, California. " In addition to exercising regularly, eating a

diet that has plenty of fruits and vegetables and is moderate in fat

is still one of the best ways we know to maintain health. "

" We want to keep in mind that this study relates only to breast cancer

survivors, " said co-investigator Cheryl Rock, Ph.D., R.D., of the

s UCSD Cancer Prevention and Control Program. " We recognize that

several other very well-designed, controlled studies have shown

clearly that eating more than five fruits and vegetables a day can

make major differences in disease risk, such as in lowering blood

pressure and reducing risk of stroke and heart disease. "

The study results refer to the typical woman on the study. The

research team emphasizes that there may be subgroups that benefited

from the intensive dietary pattern and further research will

investigate this. The 7 year follow-up time is also short for young

and middle aged women diagnosed with breast cancer. It is possible

that there will be longer term benefits particularly from reduction in

heart disease risk with this intensive dietary pattern.

Journal of the American Medical Association (JAMA); Tuesday July 17, 2007