Pathology & Prevalence of Asthma
Asthma is a common chronic respiratory disorder that is characterized by “asthma attacks” during which airflow is obstructed. The Centers for Disease Control and Prevention report that in the prevalence of asthma among children is 8.6% and among adults is 7.4%. While boys are likelier than girls to have asthma, adult women are almost twice as likely to have asthma than are adult men. African Americans have the highest prevalence of asthma, at 9.9%. The prevalence has rapidly increased worldwide in recent decades and may now affect over 300 million people. Asthma attacks frequently result in emergency department visits and hospitalizations, putting a substantial burden on the healthcare system.
Causes of Asthma
The causes of asthma are not fully known, but likely have to do with environmental exposures and genetic risk predisposition. Asthma is a complex and heterogeneous disease, so pinpointing the cause is very difficult. In people who have asthma, triggers like airborne substances, physical activity, pollutants, and stress may lead to an asthma attack. Persistent exposure to these triggers may also increase individuals’ likelihood of developing asthma, according to the Mayo Clinic.
Inflammation in Asthma
While asthma is a diverse disease, it is related to chronic inflammation in the airways and is characterized by airway hyper-responsiveness. Airway hyper-responsiveness means that the airways of asthma sufferers are excessively sensitive to stimuli, or the triggers outlined above. A 2010 review explained that, “An eosinophilic or neutrophilic infiltrate is a common feature of allergic airway inflammation and this has been correlated clinically with [airway hyper-responsiveness].” The hyper-responsiveness of the airways leads to an immune response in the airways, thereby causing a chronic inflammatory state in the airways.
Treating & Preventing Asthma Attacks
Most people who have asthma take some form of pharmacological remedy, but since asthma is an inflammatory condition, supplementing the diet with specialized pro-resolving mediators (SPMs) may also reduce symptoms of asthma and resolve the underlying inflammation that may make an individual susceptible to asthma attack.
In asthma research, the concept has emerged that chronic inflammation occurs when the body lacks effective “stop signs” for the inflammatory response. The combination of no “stop signs” and persistent allergens may make asthma attacks more frequent and more intense. We know that resolution of inflammation is dynamic and requires removal of stimuli, down-regulation of pro-inflammatory mediators, and elimination of dead cells from the site of inflammation. Without this resolution, chronic inflammation persists.
While the role of SPMs in resolving inflammation has been widely studied, additional studies specific to resolution of inflammation in asthma patients will continue to help build our understanding on the importance of resolving rather than blocking inflammatory responses. One study in patients with asthma identified that overproduction of B Cell IgE is common in this patient group. Supplementing these patients with SPMs and stimulating their production reduced IgE production in most patients. Supplementation was less effective in those patients who were taking systemic oral steroids.
Lifestyle Therapies for Asthma
There are many preventive strategies that asthma patients can implement to reduce their likelihood of having an asthma attack, such as avoiding triggers, maintaining a healthy weight, and getting regular exercise. Other lifestyle remedies include an anti-inflammatory diet. One study investigated the role of dietary fiber on the gut microbiota and resultant lung and airway inflammation in mice. The study found that the gut microbiota metabolized the dietary fiber, increased the levels of circulating short-chain fatty acids, thereby protecting the mice in the model from allergic inflammation in the lungs, often associated with allergic asthma. Another study included the implementation of an anti-inflammatory Mediterranean-style diet in adults with asthma. Small improvements were measured in quality of life and lung function when a Mediterranean diet was implemented.
Final Word
Though asthma is a very diverse health condition, common across pathologies is the inflammation of the airways and lungs. By resolving airway inflammation with SPMs, asthma patients may improve their quality of life and their lung function.
References
Kim N et al. Specialized proresolving mediators (SPMs) reduce human B cell IgE production from asthma patients. Am J Respir Crit Care Med. 2016;193:A7904.
Murdoch JR et al. Chronic inflammation and asthma. Mutat Res. 2010;690(1-2):24-39.
Serhan CN et al. Resolution of inflammation: the beginning programs the end. Nat Immunol. 2005;6(12):1191–1197.
Sexton P et al. Influence of Mediterranean diet on asthma symptoms, lung function, and systemic inflammation: a randomized controlled trial. J Asthma. 2013:50(1):75-81.
Trompette A et al. Gut microbiota metabolism of dietary fiber influences allergic airway disease and hematopoiesis. Nat Med. 2014;20(2):159–166.
