What you put in your shopping cart might help you put down the inhaler: An Indiana University review finds that many foods might stave off the symptoms of exercise-induced asthma.
"Asthma is a disease of chronic inflammation in the airways, and most foods Americans eat contribute to this inflammation," says study co-author Sally Head, Ph.D. (c), a medical student at Indiana University.
We're not telling you to leave your inhaler at home, of course—but choosing the right foods may help you use it less often. Here's what might affect your asthma.
A University of Colorado study found that people who maintained a low-salt diet (between 1,300 to 1,500 mg/day) had improved breathing post-exercise than those who followed a high-sodium diet. Why? Scientists believe sodium infiltrates smooth muscle cells like those in your lungs, and upsets the calcium levels. This imbalance triggers the cells to contract, causing labored breathing.
Though more research is needed to determine how big of a role salt plays in lung function, it doesn't hurt to cut back your sodium intake. Seventy-seven percent of Americans' salt intake comes from restaurant and processed meals—foods you should avoid anyway.
Asthma patients are known to generate more free radicals—chemicals that may produce mucous and cause the lungs and airway to narrow. Even worse, asthmatics tend to be deficient in antioxidants, which fight off the damaging effects of these molecules.
An Israeli study found that people who took a mega dose (64 mg/day) of beta-carotene for a week only had a 5 percent decrease in forced expiratory volume, a measurement of lung function, after exercising compared to a 25 percent drop for those taking a placebo. Five servings of fruits and vegetables (think: dark leafy vegetables, sweet potatoes, and cantaloupe) daily can provide up to 8 mg of beta-carotene. The Institute of Medicine recommends consuming between 3 mg to 6 mg per day.
Another study found that when participants took 30 mg of lycopene for a week, their asthma attacks weren't as severe when compared to no treatment. (Doctors recommend anywhere from 2 to 30 mg daily.) Ask your doctor about introducing a supplement into your diet, and fill up on lycopene-loaded fruits like watermelon (9 to 13 milligrams of lycopene in 1.5 cups) and tomatoes (3 mg in a medium tomato).
Yale University research found that subjects who took 500 mg of ascorbic acid (vitamin C) for two days had significantly reduced wheezing and shortness of breath after working out. Asorbic acid's seemingly protective effect may be caused by its ability to accelerate the metabolism of histamines, a chemical that can cause the lungs and airway to swell. Bolster your diet with bell peppers (they have more vitamin C than oranges) and citrus fruit since 1 in 10 men are deficient in vitamin C, according to the Centers for Disease Control.
University of Indiana researchers gave subjects an omega-3 fatty acid supplement daily for 3 weeks. (The supplement contained 3.2 grams of EPA and 2.2 grams of DHA, both types of omega-3s.) Fifteen minutes after exercising, subjects on this fish-oil supplemented diet experienced better lung function than those taking a placebo. Researchers attribute this easier breathing to omega-3s' ability to help decrease inflammation in the body. Aim for a 3-to-1 ratio of omega-6 to omega-3 fatty acids. (Americans currently eat a 10-to-1 ratio.) Too many omega-6s can actually trigger inflammation. Good omega-3 sources include salmon, tuna, and mackerel; corn and soybean products are usually high in omega-6s.
Drinking high doses of caffeine before exercising—about 3 cups of strong coffee for a 150-pound man—may make it easier to breathe after your workout, according to a Tel-Aviv University study. Caffeine, a muscle relaxant, dilates your airway, and combats the natural tendency for an asthmatic's lungs to spasm and constrict after exercising.