= Full article availableFrench researchers have found that dietary beta-carotene could help slow the natural decline in lung function with age. Comparing breathing tests in subjects eight years apart, the study discovered that those with the highest blood levels of beta-carotene—a dietary antioxidant—retained over 20% more lung function than those with the lowest beta-carotene levels. Over a 10-year span, researchers noted, the benefit of a specific increase in beta-carotene levels “approximately counteracts the effect of one year of aging.”
The study also found that beta-carotene together with vitamin E, another antioxidant, appeared to protect against decline in lung function due to smoking. Among smokers with a greater than a pack-a-day habit, those with the lowest beta-carotene and vitamin E levels showed double the decline in lung function. Lead author Armelle Guenegou, PhD, of the French national health institute INSERM cautioned, however, that smokers can’t avoid the health toll of their habit simply by eating right or taking vitamins.
The researchers began with 1,194 adults, ages 20 to 44, who were enrolled in the European Community Respiratory Health Survey. Complete data was available for comparison on 535 subjects, 40% of them lifelong nonsmokers, eight years later. The subjects’ lung function was tested by measuring forced expiratory volume at one minute (FEV1)—essentially, how much air they could forcefully exhale in a minute after taking as big a breath as possible.
“The results strongly suggest that beta-carotene protects against the decline in FEV1 over an eight-year period in the general population, and that beta-carotene and vitamin E are protective in heavy smokers,” the researchers wrote in Thorax.
The average decline in FEV1 was 29.8 milliliters a year. But the third of the subjects with the lowest beta-carotene levels lost an average of 36.5 milliliters a year, while the third with the highest levels saw an average decline of just 28.6 milliliters annually. Overall, men and those who were obese showed the greatest loss of lung power.
The researchers theorized that oxidative stress may contribute to airway obstruction over time, so they looked at blood levels of several antioxidants. Only beta-carotene and vitamin E, however, showed benefits in slowing the decline in lung power, not a related compound called alpha-carotene or vitamin A. And vitamin E was protective only in heavy smokers.
While seemingly linked to lung health, beta-carotene alone can’t keep your lungs “young,” the researchers added. They emphasized the importance of a healthy diet, especially with a mix of antioxidants and other nutrients from colorful plant foods, rather than relying on supplements.
To learn more: Thorax, April 2006.
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