A sudden shortness of breath, intense wheezing, and "coughing your lungs out” are an all too common sight in the everyday life of asthma patients. While an inhaler acts as a security blanket to alleviate these symptoms, a modification in a patient’s diet could protect them against the condition. According to a recent study, a high-fiber diet rich in fruits and vegetables, may protect against asthma and allergies by reducing inflamed lungs triggered by dust mites.
The Asthma and Allergy Foundation of America reports asthma and allergies strike one out of five Americans, or 60 million people.
Asthma patients often experience a temporary narrowing of the airways that can be triggered by allergens or irritants that are inhaled into the lungs that lead to inflamed, clogged, and constricted airways. The production of mucus could make it difficult to breathe for patients causing asthma symptoms to exacerbate. The Mayo Clinic says the cause of asthma is most likely due to a combination of environmental and genetic factors, although it still remains unclear. The exposure to various substances that trigger allergies — airborne allergens like dust mites — can trigger signs and symptoms of asthma such as lung inflammation. Now, Swiss researchers believe a high-fiber diet can alleviate the immune reaction asthma patients experience in their lungs.
Published in the journal Nature Medicine, a team of researchers from the University Hospital of Lausanne in Switzerland, sought to determine if dietary fiber could influence disease development outside the digestive tract, such as asthma, by studying two groups of mice. The groups of mice were assigned to either a normal diet, a low-fiber diet, or a high-fiber diet for two weeks. In the study, the two groups of mice were exposed to dust mites in order to evaluate the effects a fiber diet had.
There are two types of dietary fiber from food humans can consume: insoluble and soluble. Sources of insoluble fiber such as whole grains, cucumbers, and broccoli help cleanse the bowels. Oatmeal, lentils, and apples are sources of soluble fiber that slow down digestion and make you feel full longer.
The findings revealed the mice that were fed a low-fiber diet developed an increase in lung inflammation in response to dust mites. The mice that consumed a high-fiber diet had a high tolerance for dust mites compared with the other two groups of test mice. The researchers found that the immunity to allergens and a resistance to the development of asthma was attributed to the consumption of foods high in fiber.
“…dietary fiber changes the bacteria in our intestinal tract which changes the metabolites in our circulation and this is influencing how our immune cells develop,” said Benjamin Marsland, an immunologist at the university, Voice of America reports. In other words, the consumption of fruits and vegetables produces a larger amount of fermentable fiber that becomes available to the bacteria in the gut. The bacteria then converts the fiber into short-chain amino acids that enter the blood stream through the intestines and end up in the bone marrow. The bone marrow begins to form immune proteins common to allergens to produce anti-inflammatory proteins that help prevent asthma.
Although the study involved mice, and not humans, the researchers believe the digestive and lung systems of both groups are almost identical. The human consumption of high-fiber foods could possibly reduce the severity of asthma reactions triggered by allergens. The Swiss researchers plan to conduct human studies to confirm the mouse trial results in the future.
Currently, patients are advised to seek prevention and long-term control in stopping asthma attacks before they start. Despite there being no cure for the condition, asthma patients are prescribed daily medications to keep their symptoms under control. The Mayo Clinic says the long-term asthma control medications, taken daily, are the basis of asthma treatment. These medications will keep symptoms in check and reduce the likelihood of experiencing an asthma attack.
To learn more about common asthma triggers, click here.
Source: Blanchard C, Gollwitzer ES, Harris NL et al. Gut microbiota metabolism of dietary fiber influences allergic airway disease and hematopoiesis. Nature Medicine. 2014.