Fruits, Vegetables Offer Little Cancer Protection
Study Finds Protective Effect of Diet Rich in Fruits, Vegetables Modest at Best
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Fruits, Vegetables, and Cancer Risk: Results continued...
For instance, he says, those who increased their intake by about 200 grams a day, or about 1.5 servings a day, had a 3% or 4% reduced risk of getting cancer.
The effect was weaker for fruits when considered alone than for vegetables, he says.
Boffetta is not certain whether the findings hold for a U.S. population, but he speculates they probably do.
It's also possible that certain substances in specific fruits or vegetables may be more protective, Boffetta says. Lycopene, a substance found in tomatoes, for instance, has been found to reduce prostate cancer risk.
"Our purpose was really to look at the big picture," he says. "It's a little diluted when you look at the big picture."
Fruits, Vegetables, and Cancer Risk: More Opinions
Enthusiasm for fruits and vegetables to protect against cancer swelled in the 1990s, when some experts expected a diet rich in fruits and vegetables would reduce cancer risk as much as 50%, says Walter Willett, MD, DrPH, chairman of the department of nutrition at the Harvard School of Public Health, in an editorial accompanying the study.
The National Cancer Institute's 5-a-Day program was then developed in 1991.
But later studies didn't confirm such a strong link, he says.
And the new study findings, Willett says, "add further evidence that a broad effort to increase consumption of fruits and vegetables will not have a major effect on cancer incidence."
Even so, he says, a diet rich in fruits and vegetables will reduce the risk of cardiovascular disease, and ''a small benefit for cancer remains possible."
It is still possible, he agrees, that certain substances in fruits and vegetables or specific fruits and vegetables will be found to have a stronger protective effect against cancer.
The study findings are no reason to cut back on fruits and vegetables, says Connie Diekman, RD, director of university nutrition at Washington University in St. Louis and past president of the American Dietetic Association.
"While we may not understand what all fruits and vegetables can do to help prevent disease and promote health, inclusion of more fruits and vegetables can aid satiety [feeling full and satisfied], help reduce calorie intake, and certainly boost overall nutrition," she says.