This transcript has been edited for clarity.
Do six glasses of kombucha a day keep the psychiatrist away?
Hi everyone, and welcome back to the Brain Food vlog. I’m Dr Drew Ramsey. I’m on the editorial board of Medscape Psychiatry and an assistant clinical professor of psychiatry at Columbia University. I’m also the founder of the Brain Food Clinic.
These days I’m eating a lot more fermented foods and talking about them more often with my patients. That’s partly due to a great study from Wastyk and colleagues at Stanford School Medicine, titled “Gut-Microbiota-Targeted Diets Modulate Human Immune Status,” which was published last year in the journal Cell.
All of us in mental health are increasingly thinking about inflammation and the microbiome, and how those impact brain health and mental health. This is an important study for us to consider in that regard, so I wanted to make sure you heard about it.
Fibers vs Fermentation
Over 17 weeks, investigators conducted a two-arm intervention. In one arm, they took individuals from eating about 21.5 g of fiber a day all the way up to 45 g of fiber a day. In the other arm, they increased the amount of fermented foods that individuals were eating, including things like kombucha, kefir, yogurt, and kimchi. At the beginning of the study, these individuals were eating about 0.4 servings of fermented foods per day, which they increased all the way up to 6.3 servings of food a day.
Should we be eating that much fermented food? Well, the results of this study were quite interesting.
Let’s talk about the fiber group first. As so many of our patients are moving toward plant-forward or plant-based diets, they’re eating a lot more fiber. In general, that’s a great idea and one that we often consider key to having a good, healthy, diverse microbiome.
But it turns out in this study that that’s not exactly what happens. By eating more fiber and plants, you don’t actually change immune status, microbiome diversity, and immune function in the same way you do with fermented foods.
In the fermented-food group, however, there were significant findings in terms of decreasing biomarkers like interleukin-6, finding every measure of microbiome diversity increased, and showing an overall modulation of immune status.
It’s important to note that the primary outcome of the study — cytokine response score — did not change significantly in either group. So the study didn’t achieve its primary outcome. But these secondary outcomes and measures are really interesting when it comes to thinking about how we can help patients increase the diversity in their microbiome and how that can influence processes like inflammation.
I hope this study helps you think about the microbiome and fermented foods, both in your own diet as a healthcare professional but also with your patients. It may prove beneficial as you discuss mental health with them and how to incorporate science like this into their strategy. I recommend that you take a closer look at these results, and put your comments below on how things like fermented foods are influencing your practice.
I’m Dr Drew Ramsey. I’ll be drinking kombucha until I see you next time. Take care.