Risk of Lung Cancer May Be Reduced by Eating a Wide Variety of Fruits and Vegetables
For immediate release: October 12, 2000
Boston, MA--Researchers at the Harvard School of Public Health (HSPH), Brigham and Women's Hospital (BWH), and Harvard Medical School have found that diets rich in carotenoid-containing foods, which include carrots and tomato-based products, may reduce the risk of developing lung cancer. Their paper is published in the October issue of the American Journal of Clinical Nutrition. The findings come from two large cohort studies: the Nurses’ Health Study (NHS) based at BWH and the Health Professionals Follow-up Study (HPFS) based at HSPH.
Led by Dominique Michaud in the Department of Nutrition at HSPH, the researchers used questionnaires to track the dietary habits of 77,283 women in the NHS from 1984 to 1996 and of 46,924 men in the HPFS from 1986 to 1996. During those periods, 519 new cases of lung cancer were diagnosed in the women and 275 new cases in the men.
The researchers asked respondents to report the average number of times they had eaten specific food items over the previous year. They then calculated the nutrient contents of the foods. The scientists were particularly interested in a group of chemicals called carotenoids found in fruits and vegetables and known to have protective effects against oxidation and certain tumor-causing agents. They focused on the relationship between lung cancer and the individual carotenoids of alpha-carotene, beta-carotene, lutein, lycopene, and beta-cryptoxanthin.
Overall, they found that diets with a variety of carotenoids were associated with a 32 percent drop in risk for lung cancer.
When the researchers looked at individual carotenoids, they found that increased consumption of alpha-carotene was associated with a 25 percent drop in risk. The decrease in risk of lung cancer associated with alpha-carotene intake was greatest among people who had never smoked (63 percent decrease). Carrots are a major source of alpha-carotene. High intake of lycopene was also associated with a 20 percent lower risk of lung cancer. Lycopene is commonly found in tomato-based foods such as tomato sauces and ketchup. Decreases in risk were also found for intakes of beta-carotene, lutein, and beta-cryptoxanthin, but these associations were not statistically significant.
"A diet plentiful in fruits and vegetables may help reduce the risk of lung cancer, but quitting smoking remains the best way to prevent lung cancer," said Dr. Michaud.
An abstract of "Intake of Specific Carotenoids and Risk of Lung Cancer in Two Prospective US Cohorts" can be found at http://www.ajcn.org/cgi/content/abstract/72/4/990. A related editorial by David Heber, director of the UCLA Center for Human Nutrition, is featured in the same issue.
For further information, please contact:
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Harvard School of Public Health
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Boston, MA 02115
Maggie Hayden (BWH)