Asthma is characterized by lung airway inflammation. It is initiated and caused by an inappropriate immune response of the airway as well as airflow obstruction. This is caused by inflammation.
As I write in my book EAT! -- Empower. Adjust. Triumph!: Lose Ridiculous Weight, Inflammation in the body can be caused by an injury, an irritating exposure i.e., a dog or cat, or by what we eat. Inflammation is always a protective response.
However, asthmatics in general are highly symptomatic and sensitive to the world around them as they deal with a lower level of functioning in it. One noticeable symptom is secretion: Mucus secretion -- phlegm and running nose, is often the first-line defense against the barrage of irritants.
Another noticeable symptom is poor excretion. Asthmatics generally suffer from constipation or should I say poor elimination. Generally they are toxemic from excess fecal matter left behind in the colon which has been shown in studies to be a cause of wheezing. Both mucus and constipation are indicative of a toxemic state, out of which evolve the many diseases to which an asthmatic is predisposed. Toxemia, constipation and consequently inflammation, are the direct result of improper diet.
With asthma the causes are multiple and never singular. "If asthmatics were not enervated and if their bodies were not filled with toxins to the saturation point they would not be hypersensitive to proteins and other substances." (Herbert Shelton, Hygienic Review)
Since every disease starts with inflammation and asthma is always related to poor gastro-intestinal/ gut health, correcting diet is a huge factor in getting well. For recovery there needs to be an adequate supply of the normal requirements of stellar health — mental, physical and physiological rest, simple high nutrient foods, fresh air, sunshine, warmth, and cleanliness.
Studies show that overall, more frequent consumption of fruit, vegetables and fish was associated with a lower lifetime prevalence of asthma, whereas high burger consumption was associated with higher lifetime asthma prevalence. This makes sense since high amounts of animal meats and dairy are known to create mucus in the body.
In another study done on children it was found that sugary soft drinks that contained refined and high-fructose sugar were associated with higher asthmatic reactions where consumption of other beverages and consumption of fruit were not associated with increased asthma risk.