COPD is a lung condition that includes emphysema and chronic bronchitis and is often, but not always, caused by smoking; symptoms include shortness of breath, coughing, and fatigue. About 24 million people in the United States have COPD, and it is the fourth leading cause of death in the country.

Research from the government-funded Women's Health Study, included 39,876 women 45 years and older who were free of COPD before they were randomly assigned to take a placebo, vitamin E supplements (600 international units (IU) every other day) or aspirin (100 mg per day), either alone or in combination. At the end of 10 years, 760 of the 19,937 women who took vitamin E alone or with aspirin developed COPD compared with 846 of the 19,939 who took a placebo or aspirin alone – a 10 percent risk reduction.
 
The daily recommended intake of vitamin E is about 22 IU for those 14 and older; it can be obtained from sunflower oil, almonds, peanut butter, and spinach. The vitamin E intake in the study was far higher, at 300 IU per day. However, this is within the range of most over-the-counter vitamin supplements, which deliver 100 or 400 IU daily.

Several studies suggest that very high doses (above 1,500 IU per day) of vitamin E can promote hemorrhaging and interfere with normal blood clotting. So, high doses are not recommended for people taking blood-thinners and/or aspirin.

Supplements of beta-carotene, which is a precursor of the antioxidant vitamin A, should also be used with caution. Two studies found that beta-carotene supplements increased the risk of lung cancer in people who smoked more than one pack a day and drank heavily.

The best way to prevent COPD is to quit smoking. In the study, women who smoked were four times more likely than nonsmokers to develop the disease. Currently, no vitamin supplements are recommended to prevent or treat COPD. But, for people concerned about their lung health, taking vitamin E or other antioxidants is not a bad idea.

From Health.com