The Exciting Gut-Brain Axis and Fermentation Connection

This post originally began with discussing the connection between allergies and fermentation (here and here). Because two wasn’t enough; third installment, coming right up! OK, in all seriousness, these topics always take longer to discuss with any depth. For this post, I will be merging allergy issues and disorders/diseases together. Let’s look at the really exciting gut-brain axis and fermentation connection!

Animation of brain and intestines with "gut-brain axis"

Intestinal Diseases

It would seem incomplete to write all these articles revolving around the gut without discussing actual intestinal diseases or ailments. We will get to the gut-brain axis connection, but the intestines need some solo research too. So, let’s get down to business! Here are some articles about the impacts of fermented foods on specific intestinal issues.

Research on Irritable Bowel and Fermentation

Animation of various viruses and red blood cells

This research article discusses the results of a study looking at people struggling with irritable bowel syndrome. The group ate sauerkraut for six weeks. Half of the participants ate unpasteurized sauerkraut and the other half ate pasteurized sauerkraut. The results indicated that the group eating unpasteurized sauerkraut had an increase in microbial diversity and numbers over that of the pasteurized group. However, it also showed that both groups saw a decrease in their unwanted symptoms.

A research study involving people with some form of irritable bowel disease (either crohn’s or ulcerative colitis) were given kefir for 4 weeks. The findings included a reduction of negative symptoms into weeks 3 and 4. In addition, a decrease in inflammation causing bacteria was observed. Some other studies discussed talked about a change in intestinal microbes for 6 weeks post “intervention” of probiotics or fermented foods. This shows that the positive effects can last for a while. However, with a limited intervention (i.e. only one fermented food group added to the diet for a short period of time), there are, well, limitations. The beneficial bacteria need to keep being introduced to the intestines, as well as “prebiotics,” for the benefit to continue. In other words, it’s not a “cure,” but a good way to decrease the symptoms associated with intestinal issues.

Mental Health

In my first article focusing on how fermentation affects physical ailments, I hinted at the exciting gut-brain axis and fermentation connection. More and more research is being done in this area of medicine, and with compelling results. I didn’t get a chance to dive into that in the last two posts, so I will do so here.

Cumulative Mental Health Research

Looking at a fairly updated cumulative research article (2022), it seems that more and more research is being done on the microbiome and it’s connection with mental disorders. In the animal world, there is a lot of great results from studies! Because of this, research is well under way in the clinical setting. Outcomes show success in treating several issues, such as various types of stress, anxiety and depression.

However, the running theme is that the results are still not consistent, and more research needs to be done. For instance, a certain bacterial strain will be sufficient to treat anxiety, but not for depression. One possible reason is that the area(s) in the gut not functioning optimally is specific to each ailment. That’s very oversimplified, but I think the main point comes across. Another thing to consider is that the microbiome baseline for each individual will be different, in addition to any negative or positive lifestyle choices they make. Those will play a part in what works and what doesn’t.

Anxiety, Stress and Pain

Here is a great research article looking at the effects of fermented milk with added probiotics on the brain. One theory about how the gut affects the brain lies in the Vagus nerve. This nerve is key in the autonomic nervous system, controlling many of the body processes that are automatic. Examples include heart rate, digestive system, and reflexes. The Vagus nerve, as seen below, is very interconnected with the digestive system. Many receptors are actually located on the inside of the intestines. The pathway from the vagus nerve to the brain stem allows any positive or negative effects coming from the gut to affect much of the brain. Thus, one can see the possible connection between what happens in the gut with what happens in the brain.

Animation of vagus nerve from brain stem to intestines. — Picture Citation: Highpoint Mind & Movement

Research on Gut-Brain Axis and Fermentation Connection

Now, back to the research. A group of healthy women drank fermented milk with added probiotics for four weeks. Before and after that trial, scans were taken of their brains while undergoing a “standardized emotional faces attention task.” That test is basically what it sounds like. The participants are shown pictures of people with the emotion of fear or anger and they respond accordingly. These scans measure three ‘levels” of brain response, and participants in the fermented milk group had much better responses across the brain as a whole. In summary, the fermented milk helped participants handle anxiety and stress better, and it also helped them with pain sensitivity.

Here are some key points to take away from this study. One, fermented foods are helpful even for those who are already considered healthy. No matter where you’re at, there’s always room to boost your health! Two, for those who struggle with mental health (even undiagnosed), there are concrete ways to support your health. Sometimes it isn’t just in your brain…it’s in your gut! And three, this has implications beyond just mental health. How the body perceives pain is located in the brain. This big for those struggling with chronic pain. Talk about an exciting gut-brain axis and fermentation connection!

Every Day Applications

While these results are definitely exciting and significant, I do have to make sure and put in a disclaimer. I’m not a doctor. So, this is what I hear most often from those who have healed from severe disorders or diseases is this: slow is best. And sometimes (or most times), it gets messy before it gets better.

But where to start? I always love suggesting beet kvass. It’s a relatively quick ferment, easy to make, and you get a lot of bang for your buck, so to speak. Lots of probiotics, pectin, and health benefits in a small amount. Even starting off with a drop or two a day and increasing from there can make a world of difference. But as with most health improvements, consistency is key. Check out my other posts for more information on fermentation, health, and recipes to come!

Additional Resources: