By Mandy Wong | UTS Staff Writer | SQ Online (2014-15)
The pollen season is almost here. While you stock up on Zyrtec and nasal sprays to fight allergies, consider this piece of good news: eating more fiber may help soothing your symptoms.
Although it cannot be digested by humans, fiber can be fermented by our gut bacteria, which is also known as the microbiota. Due to the preference of different bacteria for different types of fiber and our varying diets, each of us has a unique gut microbiota. In general, the more fiber you eat, the greater diversity of microbiota you will have. If your gut does not have enough of these bacteria, pathogenic bacteria will accumulate and cause infection in the gut.
Now, you might wonder, “What does that have to do with my allergies?”
A research group at the University of Lausanne in Switzerland investigated the correlation between microbiota diversity and lung inflammation using mice with sterile colons. The mice were separated into two groups. The control group had a standard diet of 4 percent fiber, while the experimental group only had 0.5 percent. As expected, mice in the control group established more diverse microbiota. Then, dust mite extract, a common allergen, was used to trigger lung inflammation in both groups. Surprisingly, the extent of inflammation was much lower in the control group. It turns out that when gut bacteria ferment fibers, short-chain fatty acids are produced. These short chain fatty acids bind to G protein-coupled receptors and trigger signaling pathways that reduce respiratory inflammatory responses.
Next time you are handed a bowl of broccoli during dinner, consider taking it, even only for the sake of your allergies.
Trompette, A., et al. “Gut Microbiota Metabolism of Dietary Fiber Influences Allergic Airway Disease and Hematopoiesis.” Nature Medicine 20 (2014): 159-66. Print.