Vitamin E and Little-Known Antioxidant Vitamin Found in Oranges Promote Healthy Lungs, Study Finds

BUFFALO, N.Y. -- New research by epidemiologists at the University at Buffalo has suggested that Vitamin E and a little-known vitamin called beta-cryptoxanthin found primarily in oranges are associated with healthy lung function.

Results of the study, the first to analyze simultaneously the relationship of vitamin C, vitamin E and certain carotenoid-class vitamins with pulmonary health, appear in the current (April) issue of the American Journal of Respiratory and Critical Care Medicine.

"Impaired lung function is associated with an increased risk of dying," said Holger Schunemann, M.D., UB research assistant professor in the Department of Social and Preventive Medicine and lead author on the study. "Therefore, it is important to determine the factors that could influence lung function."

Schunemann has focused his research on determining the relation of lung function with these factors. He published an earlier study showing that oxygen molecules known as free radicals were implicated in impaired lung function. The current research investigated the association between blood levels of certain antioxidant vitamins known to dispose of free radicals and the results of lung function tests.

Previous studies on the effect of antioxidant vitamins, particularly beta-carotene, on lung function had used dietary intake to estimate antioxidant level and results were inconsistent. This investigation measured blood-serum levels of vitamin C, vitamin E, retinol (a form of vitamin A) and the carotenoids beta-crytoxanthin, lutein/zeaxanthin, beta-carotene and lycopene in 1,616 randomly selected residents of Western New York.

All participants performed lung function tests to measure the volume of air they could expel in one breath, known as forced vital capacity (FVC), and the volume expelled in one second, called forced expiratory volume1 (FEV1).

Analysis of antioxidant levels and lung function based on these tests showed that lung function was better as serum levels of antioxidant vitamins increased. Vitamin C, vitamin E, beta-crytoxanthin, lutein/zeaxanthin, beta-carotene and retinol were positively associated with FEV1, and beta-carotene was positively related to FVC when the vitamins were considered individually.

However, when all vitamins were considered together, beta-crytoxanthin and vitamin E showed the strongest relationship to the two measures of lung function. Participants who had half of the average concentration of these vitamins in their bloodstream showed a reduction in lung function equivalent to 1-2 years aging of the lungs.

Retinol also was associated with pulmonary health, specifically with FEV1.

Low levels of both vitamin C and vitamin E were associated with the lowest results on the tests, but vitamin E had the stronger relationship.

"Our findings indicate that carotenoids and retinol, in addition to vitamin E, may play a role in respiratory health and that the most important carotenoid may not be beta-carotene, as previously thought," Schunemann said. "Evaluating this association is important because persons with reduced pulmonary function are at increased risk factor of dying from chronic disease. Antioxidant vitamins could help reduce that risk."

Additional UB researchers on the study were Brydon J.B. Grant, M.D., of the departments of medicine and physiology; Jo L. Freudenheim, Ph.D., Paola Muti, M.D., Richard W. Brown, Ph.D., and Julie Drake, all of the Department of Social and Preventive Medicine; Robert A. Klocke, M.D., professor and chair of the Department of Medicine, and Maurizio Trevisan, M.D., professor and chair of the Department of Social and Preventive Medicine.

The study was supported in part by a grant from the National Institutes of Health and from the German Research Foundation.