“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.

Asthma

chasing after something fast—say, a frisky toddler. You’ll soon be gasping for air the way someone with asthma does during an attack. It’s a frightening experience.

The usual setup for an attack combines an allergic (or supersensitive) immune system, an inherited trait, with exposure to environmental allergic triggers such as animal dander, mold spores, and pollen or to environmental irritant triggers such as air pollution, cold air, and cigarette smoke. Other activators can include respiratory infections, colds, laughter, crying, anger, exercise, and stress.

There are two major components of asthma. One is noisy—the wheez­ing, coughing, choking, can’t-catch-your-breath feeling. That’s the part most people call an asthma attack, or bronchospasm and congestion.

The second part of asthma is quiet. It is called inflammation—the part of asthma that is always present but not always noticed. Just as sunburn may not be evident until long after you’ve come in from the sun, airway inflam­mation is not noticeable until the damage has become so extensive that an asthma attack begins.

During an asthma attack, the muscles surrounding the lungs‘ bronchial tubes contract, narrowing airways and making it hard to breathe. People with chronic asthma also have inflammation in their lungs. The membranes lin­ing the inner walls of the air passages become swollen and leaky. And the glands within these walls produce excess mucus. That makes it harder for the lungs to do their job of gas exchange, picking up oxygen from the air and dumping carbon dioxide out of the body.

Asthma is usually treated with drugs that open airways and reduce inflammation as well as by avoiding substances that trigger attacks. For some people, that means finding a new home for a family pet, exchanging the wall- to-wall carpeting for linoleum, or steering clear of cigarette smoke, car and truck exhaust, and chemical fumes.

Dietary counseling for asthma, especially in young children, may include testing for possible problem foods. But it doesn’t often include recommenda­tions for vitamin or mineral supplements, experts say. Nevertheless, some research suggests that certain nutrients may play roles in asthma by reducing airway sensitivity and dampening inflammation.

Note: If you’re feeling well enough to reduce your dosage of asthma medication, do so only under medical supervision, experts warn. Stopping asthma drugs abruptly could lead to problems.