Could a High Fiber Diet Help Prevent the Flu in Asthmatics?
Each autumn, influenza rears its ugly head and begins infecting people all over the globe. By the winter holidays, or shortly thereafter, people begin to fall ill with severe respiratory symptoms. In fact, up to 20% of people are infected each year. The flu is not fun for anyone, but in people with asthma it greatly worsens symptoms and threatens asthma control.
Of course, your best defense is an offense. In other words, get your annual flu shot before the influenza viruses begin circulating in earnest. Flu vaccines, at their best, bolster your immune system enough to prevent you from actually getting the flu. And even if you should still fall ill with the flu, your course of illness should be shorter and less severe.
There are also antiviral medicines that can be used to fight a flu infection, once it begins, if necessary.
But, what if there was a more "natural" approach to preventing the flu? Well, researchers recently released pre-clinical study results suggesting the possibility of exactly that. Perhaps this will lend credence to the idea that I discussed in my post, "Asthma and Gut Health: What’s the Connection?" In that post, I explored the possibility that gut health might influence respiratory and immune system health.
Details of the Study
In the May 15, 2018 issue of the journal Immunity, researchers described a study they had done with mice. They researched using a high-fiber diet to impact the immune system. In this study, they fed mice a diet supplemented with either the highly fermentable fiber inulin or short chain fatty acids (SCFAs). What they found was that this diet affected the immune system in 2 different ways:
- First, it decreased the innate immune response that is typically associated with tissue damage.
- Second, it enhanced the adaptive immune response that is charged with eliminating pathogens.
The researchers explained that treatments studied in the past usually either turn the immune system on of off. But, with the dietary fiber, they were surprised to find that it turned off part of the mice's immune system, while turning on another, completely unrelated part of their immune system. These two-pronged benefits occurred because of changes in the composition of gut bacteria in the mice. Those changes led to a growth in the production of SCFAs through the fermentation of dietary fiber.
Taking their analysis a bit further, they also found that the dietary fiber and the resultant immune system changes actually protected the mice specifically against a flu infection.
Where Do We Go From Here?
All this is very exciting, but we're talking about mice, not humans. Could humans prevent the flu simply by eating a high-fiber diet?
Looking at this research along with past studies, it does seem evident that the typical Western diet of high sugar, high fat, low fiber foods does not promote health. In fact, that type of diet could make you more susceptible to inflammatory diseases like asthma, while decreasing your protection against infections, such as the flu. As to whether, eating high-fiber will actually prevent flu in humans, we just don't know enough yet.
Authors of this study say they plan to do similar dietary intervention studies in humans to see if the results translate. These studies would look at:
- How dietary changes influence the immune system
- How changes in the gut can influence lung diseases
They say that further study may also help us understand if dietary fiber might enhance other asthma therapies or improve vaccine effectiveness.
So, the jury is still out in terms of definitive proof. But we already know there are many health benefits to increasing the fiber in our diets. So, I for one, will keep eating my fiber and hoping for the best come flu season! And also I'll be getting my flu shot. Can't have too much health insurance!
Have you ever gotten "moon face" as a side effect of prednisone?