WASHINGTON (Reuters) - Teenagers who do not get enough of the nutrients commonly found in fruits and fish are more prone to underperforming lungs, asthma, coughing and wheezing, researchers reported on Monday.
They found that teens with the lowest intake of fruit and especially vitamin C had weaker lungs compared to the others. Teens who ate less vitamin E, found in vegetable oil and nuts, were more likely to have asthma, Jane Burns and colleagues at the Harvard School of Public Health found.
Based on these findings, Burns said that current recommended dose of vitamin C, 85 mg a day, may not be enough for teens to have healthy lungs.
Many studies have connected unhealthy eating habits with lung problems.
So Burns and colleagues surveyed and tested 2,112 12th-graders from the United States and Canada.
In keeping with previous surveys, they found that many teenagers ate less than the recommended amounts of fruits and vegetables, they reported in their study, published in the journal Chest.
Only 11 percent took vitamin supplements on a daily basis.
Teens who consumed less fruit and lower levels of omega-3 fatty acids were more likely to have asthma and respiratory symptoms such as wheezing.
Even moderate amounts of the omega-3 fatty acids were protective, Burns said in a telephone interview, though fish, the best source of omega-3, was particularly unpopular with teenagers. Omega-3s are also found in walnuts and flaxseed oil as well as some green vegetables.
Omega-3 fatty acids may work by counteracting inflammation in the lungs. The antioxidant properties in vitamins C and E as well as other compounds found in fruit likely protect cells lining the airways from free radical damage, Burns said.
Smokers who also shirked vitamin C increased their odds of coughing, wheezing and developing phlegm, Burns said.
A quarter of the adolescents they surveyed were smokers.
More than 80 percent of teens were getting their recommended doses of vitamin C -- mainly from fruit punch, the researchers found. “I wouldn’t advocate drinking fruit punch, but at least they’re getting their vitamin C from somewhere,” Burns said.
The researchers did not account for poverty and other factors that often distinguish less-healthy eaters and may explain their findings.
Burns added that there are several different ways to get the necessary nutrients.
“I think vitamin supplements are fine. I think adding vitamin D to orange juice is fine. I do think there are benefits that we don’t fully understand to eating whole foods like fruits and vegetables and fish,” she said.