Eating an apple a day is supposed to keep the doctor away, and now researchers have found one reason the old adage might be true. Men who eat five or more apples a week appear to have better lung function than men who do not eat the fruit. This finding is consistent with results from other large epidemiological studies which have reported positive associations between lung function and the consumption of fresh fruit. The study could not determine if the apples themselves are responsible for better lung function, or if apple-eaters had healthier lifestyles in general.

However, apple consumption did not appear to protect against a decline in lung function during the study. Changes in lung function over the 5-year follow-up period were not associated with changes in diet of any kind, according to the report. The researchers determined that vitamin C was not related to lung function after they took into account other factors that affect the lungs. Instead, another antioxidant might be involved, according to the researchers. Apples contain a flavonoid called quercetin, which is also found in onions, tea, and red wine. This antioxidant may help to protect the lungs from the cellular damage caused by smoking and air pollution.

Thorax January 2000;55:102-108