CAMBRIDGE, Massachusetts, August 1, 2007 (ENS) - Most teenagers in the United States and Canada don't choose to eat fish and fruit nearly as often as they choose burgers and chips. Now, a study of more than 2,100 teens conducted by the Harvard School of Public Health and Health Canada has found that those who eat the least fruit and fish have the weakest lungs.

"Most of the adolescents in our study had dietary intakes of fruit, vegetables, vitamin E, and omega-3 fatty acids below recommended daily levels," said Jane Burns, a researcher at the Harvard School of Public Health. Fish are high in healthful omega-3 fatty acids.

"Low intakes were associated with lower lung function and increased odds of asthma and chronic bronchitis," said Burns.

About 20 percent of people under 18 years old cough, wheeze and suffer from asthma and bronchitis.

Smokers are four times more likely to experience these lung problems than non-smokers. The researchers found that the combination of smoking and not getting enough vitamins and other nutrients increases the risk of chronic bronchitis seven-fold.

To control for air pollution, teens were studied only in mid-sized suburban and rural communities, including Charlottesville, Virginia; Aberdeen, South Dakota; Monterey, California; Leamington, Ontario; Yorktown, Saskatchewan; and Penticton, British Columbia.

The 2,112 high school seniors took huffing and puffing tests to measure lung function and answered questions about their eating habits, respiratory health, medications, smoking and exercise.

Results showed that 86 percent did not eat the recommended five to nine servings of fruits and vegetables a day. Teens who consumed the least amount of vitamin E, either in foods or supplements, were most likely to have asthma.

Present in green vegetables, vegetable oils, nuts, cereals and meats, vitamin E is essential for maintaining normal lung cell structure and protecting tissues from damage by pollutants.

Vitamin C, found in oranges, lemons, tomatoes, greens, and strawberries, is also necessary for protecting lungs and other organs from infection.

Most of the teens tested got the daily recommended amount of C mainly from fruit punch, which Burns says is not the best way. Those teens who barely consumed the recommended amount did not have the healthiest lungs.

Burns suggests raising the daily amount from the 85 milligrams now recommended to 100 milligrams.

Fish proved to be especially unpopular with the tested teens, although the omega-3 fatty acids in fish help protect lungs against inflammation.

Teens who dislike fish or greens can get their vitamins through supplements.

"Vitamin supplements are fine but they may not be enough," Burns said. "Supplement use does not completely alleviate the problem since omega-3 fatty acids and other nutrients may not be included. Also, evidence suggests a greater biological effect from eating whole foods than from supplements alone."

Burns and her colleagues at Harvard and Health Canada published their findings in the July issue of the medical journal "Chest."

Other researchers have found that coughing, wheezing, and asthma in adults and young children are associated with diets low in fruit, vegetables, vitamins, and omega-3 fatty acids, but this is one of the largest investigations of the connection among teens.

Copyright Environment News Service (ENS) 2007. All rights reserved.