Intensive Diet Doesn’t Prevent Breast Cancer

An intensive diet of fruit, vegetables and fiber does not prevent a recurrence of breast cancer, a US study released this week found.

But healthy eating habits and frequent exercise can nonetheless dramatically reduce the chance of remission while providing additional health benefits.

“It’s not as bad news as you think at first glance,” said study coauthor Cheryl Rock, a professor at the University of California San Diego’s medical school.

“It’s an anti-going overboard study,” she said. “You don’t have to spend your day juicing and at the farmer’s market (to stay healthy.)”

Women who ate at least five servings of fruit and vegetables a day and exercised six times a week cut their cancer recurrence in half, Rock said.

There were no notable improvements among women who changed their diet more drastically.

But women who ate significantly less than the recommended five servings a day had a 40 percent higher risk of recurrence or new primary cancer, Rock said.

The study followed 3,088 breast cancer survivors for between six and 11 years to see if doubling the recommended intake of fruit and veggies, cutting fat and increasing fiber would prevent remission.

Most of the women were in their 50’s and 75 percent were already eating an average of five servings a day of fruit and vegetables before the study began.

Half the women were given cooking classes and telephone counseling to help them adopt the new, intense diet. They managed to increase their fruit and vegetable intake to an average of 12 servings a day, substantially cut fat and increase fiber.

The other half were told to follow standard US government recommendations which can be found at

Both groups had a breast cancer recurrence rate of about 17 percent and a mortality rate of 10 percent.

This was a significant improvement over the typical recurrence rate of 30 percent, Rock said.

The study does not prove that these intense diets may not be helpful over the long-term, Rock said.

“Is there a role for eating this way in primary prevention?” she asked. “Maybe you have to start that way at 15. Maybe they were too far along with the internal metabolic changes.”

The authors will be further examining the results to see if women with a particular genetic profile can be helped by the more intense diet, Rock said.

“We want to keep in mind that this study relates only to breast cancer survivors,” she said.

“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 was published in the July 18 edition of the Journal of the American Medical Association.

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