Inflammation is essential for surviving injuries and infections, but when it becomes chronic, inflammation becomes one of the leading causes of illness and disease. The preventative solution could be as simple as changing your diet, as a recent Stanford School of Medicine study found that diets designed to nourish gut bacteria will also lower inflammation. 

There is a diverse group of bacteria living within your gut that support digestion. They also make up 70% of your immune system. In the same way that your body needs nutrients, these microorganisms require nourishment to thrive. To maintain a greater diversity of bacteria, and therefore a stronger immune system, how you nourish them will make all the difference.

There is currently a wide body of evidence supporting the influence diet has on gut health. There is also extensive evidence showing that low microbiome diversity is linked to poor gut health and inflammatory conditions like obesity, diabetes, and heart disease. Based on this research and previous findings that fiber and fermented foods are most beneficial for gut health, researchers at Stanford School of Medicine developed a new proof-of-concept study.  

This recent trial involved 36 healthy adults assigned randomly to a 10-week diet with high-fiber or fermented foods. Blood and stool samples were collected to analyze microbial diversity and inflammatory protein levels during a 3-week pretrial period, during the 10-week trial, and during a 4-week post-trial period. Researchers discovered that:

♦ Eating fermented foods like yogurt, kefir, kombucha tea, and fermented vegetables led to an increase in microbial diversity.

♦ Four types of immune cells showed less activation among the fermented food group.

♦ Levels of 19 inflammatory proteins, measured in blood samples, were reduced among the fermented foods group.

♦ Microbial diversity among the high-fiber group remained stable.
None of the 19 inflammatory proteins were reduced in the high-fiber group. 

While it was expected that increased fiber would help improve microbial diversity and therefore support immune responses, this was not the case. The results did show that more carbohydrates were present in stool samples, indicating that fiber was not completely digested. Research will continue with high-fiber diets as researchers believe that with a longer timeframe, gut bacteria will adequately adapt to the increased fiber intake, digest it more efficiently and yield different results. 

The main discovery was that increased consumption of fermented foods was linked to an increased diversity of gut flora, corresponding to lower inflammation levels. The more beneficial bacteria that reside in your gut, the lower the risk for chronic and damaging inflammation. This study showed that short-term dietary changes could rapidly alter gut health, providing long-term immunity benefits. 

The Stanford research team now turns their focus to uncovering the mechanisms by which diets alter microbiome diversity. The discovery that diets heavy in fermented food can promote microbial diversity and reduce inflammatory proteins can be instrumental in developing natural therapies that combat inflammatory conditions. If you really are what you eat, then you will be healthy with a fermented-food diet.

Journal reference: Hannah C. Wastyk, et al. (2021). Gut-microbiota-targeted diets modulate human immune status. Cell.