Study: Gut Bacteria, High Fiber Fights off Asthma, Clears Airways

Researchers with Lausanne University Hospital in Switzerland published work recently in the journal Nature Medicine, where they detailed how lab mice eating plenty of fruits and vegetables saw an increase in the amount of fatty acids in the bloodstream, affecting how the immune system functions in the lungs. Ultimately, the latest piece of research indicates such a diet—one with plenty of dietary fiber—can ward of asthma.

These plant foods—rich in dietary fiber—affect the production of beneficial microbes or gut bacteria. Previous research has linked this effect to the prevention of intestinal cancer. But now, we know the effects reach much further than the digestive system.

In an effort to test the mice’s vulnerability to allergic asthma, the researchers tested three groups of mice—one on a low-fiber diet, one on a standard fiber diet, and the third on a standard diet that had been enriched with “fermentable fibers.”

When exposed to dust mites—normally known to trigger allergic reactions—the mice on the lowest-fiber diet had the strongest allergic reaction. Those with the best built-in defenses to the allergens were those on the standard diet supplemented with additional fiber.

Read: The 2 Herbs for Asthma, COPD, and Chronic Bronchitis

Interestingly, it’s the lowest-fiber group whose diet was most similar to the average American’s diet.

Under the direction of lead researcher Benjamin Marsland, the researchers determined the benefits are the result of a chain of reactions:

“First the fibers reach the intestine, where they are fermented by bacteria and transformed into short-chain fatty acids. These acids then enter the bloodstream and influence the development of immune cells in the bone marrow. Attracted by the extract of house dust mites, these immune cells wander into the lungs, where they eventually trigger a weaker allergic response.”

As reported by MedicalNewsToday, our consumption of fruits and vegetables has declined in the US over the past five decades. During that same period, the rates of asthma have gone up. These two facts are likely linked.

The research may not be surprising, as we know the effects of eating a diet high in processed foods is bad for several reasons—one of the biggest of which is the lack of fruits and vegetables, but it is further fuel and motivation for eating a diet rich in plant foods.