Apart from vaccination, eating more fiber is one of the few things you can do to help protect yourself against lung infections such as Corona and Influenza.

Let me give you the facts first: Dietary fiber has a significant protective effect on infections of the lungs such as Corona or Flu. This may make increasing fiber intake, a viable way of enhancing protective immunity and reducing the severity of an infection. Increasing dietary fiber consumption by 5g per day (roughly a handful of berries or nuts) is an easy way to add this life-saving nutrient.

These results come as a surprise. Why should fiber (basically eating more fruit, vegetables, grains, seeds, or herbs) have any influence on how your body fights a viral disease? The answer to this is what the past decades of research is beginning to uncover about this miracle ingredient. 

Fiber, through its central influence on our gut microbiota, is known to have a positive effect on inflammation in general, and diseases of the airways that involve an immune response from the body in particular.

Among many other benefits of fiber, it is metabolized by some of our gut bacteria into short-chain fatty acids. These have a profound effect on our immune system in terms of reducing inflammation and a wide range of other benefits. Several studies also show that the positive effects relate to the development of protective immunity and reduced immune system-linked tissue damage when lungs are infected with the Flu or Coronavirus.

While all deliberate infection studies have been done in animals, one study with over 400 students showed a 40% reduction in the percentage of days with cold or flu in normal-weight individuals with 5g of additional fiber consumption per day.

This is an exciting area of emerging research and yet another piece of the puzzle that helps us understand why increasing fiber consumption has one of the most profound effects on human longevity.

This is a guest post. Any opinions expressed are the writer’s own.

1. Maslowski K.M. et al.;  Regulation of inflammatory responses by gut microbiota and chemoattractant receptor GPR43,  Nature. 2009; 461: 1282-1286
2. Trompette A. et al.; Gut microbiota metabolism of dietary fiber influences allergic airway disease and hematopoiesis., Nat. Med. 2014; 20: 159-166
3. In particular, acetate, propionate, and butyrate
4. Inflammation is basically the body’s way of dealing with injury and infection.  In general, it is a positive function.  For example, when you cut yourself, or after a mosquito bite, the inflammatory response is pretty visible and supports the healing process.  These short-term inflammations are normal and the way your body mobilizes its defense and repair ability.  But over-reactions (e.g., as in the case of severe infection and chronic inflammation as in the case of adiposity (high levels of fat tissue), continuous irritation as in the case of asbestos or smoking in the lungs, or even stress and low movement can be damaging over the long run.
5.  Corrêa-Oliveira R, et al.; .Regulation of immune cell function by short-chain fatty acids. Clin Transl Immunology. 2016;5(4):e73. Ríos-Covián, David et al. “Intestinal Short Chain Fatty Acids and their Link with Diet and Human Health.” Frontiers in microbiology vol. 7 185