“So far, however, all we have are primarily case-control studies,” said doctor. Those studies that looked at actual supplementation with micronu­trients or vitamins did not show significant improvement of lung function, with the exception of one study, according to professional nutritionist. In that study, people with asthma who took 100 micrograms of sele­nium daily for 14 weeks had improved lung function and were less sensitive to airway-constricting inhalants than when they were taking placebos (inac­tive pills).

Lung Infection

Selenium is needed in the body to produce glutathione peroxidase, an enzyme that helps protect cells by breaking down biochemicals associated with inflammation.

It’s too soon to say for sure whether supplementing a regular diet with selenium will help people with asthma. People who want to try it can safely take 100 micrograms, the amount found beneficial in the Swedish study. (The Daily Value is 70 micrograms.)

Studies have shown that people generally get about 100 micrograms of selenium a day from the average healthy diet. Don’t overdo it with selenium, say nutrition experts. A daily intake of 400 micrograms from foods and sup­plements is considered the upper limit of the safe range.

Antioxidant Compounds

People who want to take other antioxidant nutrients can safely supple­ment with up to 400 IU of vitamin E and 6 milligrams of beta-carotene a day. It’s a good idea to talk to your doctor before taking more than 400 IU of vitamin E daily. However, a diet of fish, whole grains, fruits, and fresh vegetables may be the best approach to prevention of asthma.

Some studies suggest that in addition to the nutrients mentioned above, calcium, zinc, copper, and vitamin D may all play supporting roles in easing the symptoms of asthma.