The foods in the anti-asthma diet that provide magnesium also provide potassium. Just a little additional potassium in the diet can work wonders. High doses of steroids or overuse of inhalers can deplete potassium to dangerous levels requiring emergency room treatment. An apple or a banana a week can prevent this reaction. Scientists at the Keck School of Medicine at the University of Southern California found that children who consume the lowest levels of potassium in fruits and vegetables have the lowest breathing capacity.
All sources of potassium, however, are not equivalent. Apples and pears are great sources of potassium that also contain flavonoid compounds providing additional protective benefit. In May 2004, [no “the”] Nutrition Journal (available to you free of charge over the internet at www.nutritionj.com) published a report finding a specific benefit of apples and oranges in reducing asthma.
In a Finnish study involving 10,000 men and women, the flavonoids quercetin, hesperitin, and naringenin, found in apples and oranges, protected against asthma. Other fruits and vegetables, such as grapefruit, cabbage, and various fruit and vegetables were not associated with a decreased risk of asthma.
A study of 13,000 people in the Netherlands found that consumption of apples and pears was positively correlated with lung capacity and negatively correlated with chronic obstructive pulmonary disease. In both of these studies, however, the amounts of fruits and vegetables consumed were low, far less than the nine servings a day I recommend.
You first choice of potassium source for asthma, however, should be apples, pears, or orange juice. If you do not already eat fruit and drink fruit juices on a daily basis, the chances of your having an allergy to citrus, apples, or pears are very low.