Controlling your asthma with a healthy diet

Asthma is a harmful disease that can affect children and adults. Here's a quick guide to help you control asthma with a healthy diet.

There are no specific foods that prevent asthma, but some may lessen its complications.

• Omega-3 fatty acids, found in salmon, mackerel, sardines and other cold-water fish, have an anti-inflammatory effect and may counter bronchial inflammation.
• Evidence continues to grow on the protective effects of fruits and vegetables on lung function. Eat at least five to 10 servings of fruits and vegetables daily and include one citrus fruit. These foods all provide a variety of vitamins, minerals and antioxidants important for healthy lung function.
• Vitamin C helps promote a healthy immune system and may be helpful in reducing wheezing in children with asthma.
• Potassium deficiency is another potential problem; it can be prevented by eating ample citrus fruits, bananas, dried fruits, berries, beets, tomatoes and green leafy vegetables.
• Some studies have linked weight gain with adult-onset asthma. In addition, when obese people with asthma lose weight, there can be an improvement in asthma symptoms. Like everyone else, asthma patients need to consume a healthful, balanced diet, but this is sometimes difficult if allergies require eliminating entire food groups (for example, milk and other dairy products). A dietitian can recommend substitutes or supplements to ensure maintaining good nutrition.
• Epinephrine and other bronchodilator drugs can cause feelings of nervousness, which are exacerbated by caffeine. It may be advisable to switch to decaffeinated coffee.

More prevalent — and potentially deadly — asthma triggers are sulfites, preservatives that are added to many foods to prevent spoilage and preserve colour and texture.

• They are especially common in dried fruits, dehydrated or instant soup mixes, instant potatoes, dough conditioners, wine, beer and white grape juice.
• Anyone sensitive to sulfites should carefully check food labels for any ingredient ­ending in sulfite — for example, potassium bisulfite — as well as sulfur dioxide.
• In addition to precipitating an asthma attack, sulfites sometimes lead to ­anaphylaxis in people hypersensitive to them.
• Coffee and tea are sources of theophylline, a bronchial muscle relaxant used to treat asthma in people who are not sensitive to salicylates.
• Anyone taking a theophylline drug, however, should avoid large amounts of tea to prevent an overdose.

Warning: asthma drugs can create nutritional problems.

• Long-term steroid use, for example, ­causes bone loss; vitamin D and calcium supplements may be needed to strengthen bones.

Help control your asthma with a healthy diet and be sure to talk to your doctor for more information.