Vitamin C and Lung Function

Breath of Fresh Air

Lung function naturally deteriorates as we age, but regular exercise and certain nutrients can help put the brakes on that deterioration. And new research shows that avoiding high intake of a certain type of common food may help you avoid the most serious type of lung function decline.

Waiting to inhale

Chronic obstructive pulmonary disease (COPD) is an umbrella term that refers to asthma, emphysema, chronic bronchitis, or any combination of the three. According to the World Health Organization, almost three million people die of COPD related complications each year, and COPD is the fourth leading cause of death in the U.S.

Previous studies indicate that the type of lung damage that leads to emphysema may be triggered in part by nitrites, which are added to cured meats such as hotdogs, ham, and processed lunchmeats. Researchers at Columbia University Medical Center in New York City conducted a cross-sectional study to determine if nitrites intake might be associated with COPD risk.

The Columbia team studied dietary and health records of more than 7,300 subjects who participated in the Third National Health and Nutrition Examination Survey. The average age of the subjects was 64. Analysis showed that frequent consumption of cured meats (14 or more servings per month) was linked with “an obstructive pattern of lung function and increased odds of COPD.”

This study doesn’t supply enough evidence to conclude that cured meat intake is a direct cause of COPD because the researchers also found that subjects who frequently ate cured meats were also prone to have a lower intake of fruits, vegetables, fish, vitamin C, and vitamin and mineral supplements. But even when researchers made adjustments for these and other factors (such as smoking – a major cause of COPD), the link between cured meat intake and COPD was still significant.

A spokesperson for the American Meat Institute told Reuters Health that nitrite levels in cured meats have declined in recent years.

Sandwich with a side of C

The Columbia study also found that the subjects who consumed the most cured meats tended to be male cigarette smokers of lower socioeconomic status. But that doesn’t mean that non-smoking, successful professional women are free of risk. I have a friend who meets that description, and she admits that nearly every day she wolfs down a turkey sandwich at her desk as she continues to work. So she would easily qualify in that 14-or-more servings per month group. But besides being smoke-free, here’s what will probably keep her safe from nitrite-induced COPD: She takes supplements that insure an ample intake of vitamin C.

In the e-alert “C-ing Stars” (6/12/02) I told you about a UK study that investigated the relationship between lung function and the intake of magnesium, and vitamins C, E, and A. The UK team surveyed more than 2,500 subjects to assess the relationship between diet, asthma and COPD. Nine years later, approximately one half of the original group participated in a follow-up survey, as well as tests that determined breathing levels.

After analyzing the data, researchers reached two important conclusions:

1) Subjects who consumed higher amounts of vitamin C had better lung function than those with lower levels of vitamin C intake
2) Higher amounts of vitamin C and magnesium intake were associated with significantly improved lung function in subjects suffering from asthma or COPD

The researchers didn’t offer a recommendation about the dosage level of vitamin C required to reap the protective benefits, but the study indicates that the average participant in the survey was not supplementing with mega-doses.

Jenny Thompson Sources:
“Cured Meat Consumption, Lung Function, and Chronic Obstructive Pulmonary Disease among United States Adults” American Journal of Respiratory and Critical Care Medicine, Vol. 175, No. 8, 4/15/07,
“Study Ties Cured Meats to Higher Lung Disease Risk” Will Dunham, Reuters Health, 4/17/07,