In my video Preventing Asthma With Fruits and Vegetables, I highlighted an international study of asthma and allergies involving more than a million kids. The study found a consistent inverse relationship between prevalence rates of asthma, allergies, and eczema and the intake of plants, starch, grains, and vegetables. Researchers speculated “over a decade ago that if these findings could be generalized, and if the average daily consumption of these foods increased, an important decrease in symptom prevalence could be achieved.” No need to speculate any more, though, because plants were finally put to the test.
Researchers have proposed that “by eating fewer fruits and vegetables, the susceptibility to potentially harmful inhaled substances of the population as a whole may be increased because of the reduction in antioxidant defenses of the lungs.” The thin lining of fluid that forms the interface between our respiratory tract and the external environment is our first line of defense against oxidative damage. Oxidative damage is important in asthma, contributing to airway contraction, excessive mucous production, and hypersensitivity. Antioxidants protect against oxidative stress, so our lung lining contains a range of antioxidants our body makes itself, as well as those obtained from our diet, particularly from fruits and vegetables.