It would seem that there is no way humans could live on Earth without bacteria known as probiotics. Probiotics also make an important connection, via the vagus nerve, to the brain. Known as the gut brain connection. These microoraganisms control us much more than we may want to think.

There have been some interesting studies done with mice and the probiotic bacteria, lactobacillus. In one such study at McMaster University in Canada. Mice were placed in a stressful situation to measure anxiety and stress response. One at a time a single mouse was placed in a bucket of water. With no way to escape. The goal of this study was to see how gut bacteria might influence brain behavior and stress response.

The control group were just normal mice. Eating normal mice food. The study group had been fed lactobacillus rhamnosus, a probiotic bacteria. The control group, when placed in the water, swam frantically, trying to escape until they were exhausted.

The study group—the one fed lactobacillus rhamnosus—swam in a less frantic, thoughtful manner. After the mice had given up and stopped swimming. The researchers removed them from the water and tested for corticosterone. Corticosterone is the mice version of the human stress hormone, cortisone. They found that the study group, the mice fed lactobacillus rhamnosus, had significantly lower levels of corticosterone than the control group.

The Vagus Nerve

For the second part of the study the scientists severed the vagus nerve. The vagus nerve is the longest nerve in the human body. It contains both motor and sensory functions and runs from the medulla oblongata all the way to the gut. For our purposes here you just need to understand that it connects the stomach to the brain. In man and mice.

When the scientists ran the same tests after severing the vagus nerve. They found that the lactobacillus rhamnosus had absolutely no effect on anxiety reaction or corticosterone production.

This finding suggests that the gut brain connection has an important linkage—more importantly, that there is a link between bacteria in the stomach and chemical function in the brain. Lactobacillus rhamnosus was shown to minimize the production of the fear-inducing hormone corticosterone. This in turn, helped to minimize stress and fear reaction.

Stress And IBS

Another study worth mentioning was done by Jay Pasricha, M.D., Director of Johns Hopkins Center for Neurogastroenterology. In terms of constipation, diarrhea, and Irritable Bowel Syndrome (IBS), researchers are finding that irritation in the gut ends up sending signals to the brain that trigger mood changes. “For decades, researchers and doctors thought that anxiety and depression contributed to these problems. But our studies and others show that it may also be the other way around,” Pasricha says. “That’s important, because up to 30 to 40 percent of the population has functional bowel problems at some point.”

What doctor Pasricha is saying. Stress, anxiety and depression are caused by bowel problems, rather than contributing to the onset of these problems. Scientists have just located the tip of the iceberg when it comes to the gut-brain connection. There are many studies out there showing how gut bacteria affect mood, thinking clarity, and so on.

If you want to learn more. Here are a couple books you should check out; Giulia Enders, Gut: The Inside Story of Our Body’s Most Underrated Organ and The Mind-Gut Connection by Emeran Mayer, MD. If you are interested in learning more about your body and how it works. This knowledge will empower and motivate you to eat healthier. It will also improve your quality of life. 

Making Your Own Probiotic Rich Foods

Making your own fermented foods at home is a fun hobby. In one sitting you can make months worth of probiotic snacks that contain lactobacillus. If you need help to get started. There’s an excellent book by Sandor Katz called the Art of Fermentation. This book has all the information and recipes you will ever need to ferment almost anything at home.

Something else to keep in mind. There really shouldn’t be more than a gram or two of sugar in any type of probiotic food. Ideally, all of the sugar will be fermented out. So with store bought items check the added sugar content. And it’s not just sucrose. Sweeteners have 56 different names, which I will detail more later on.

Probiotic foods like sauerkraut, tempeh, miso and pickles shouldn’t have any sugar at all. Check the label if you are buying kimchi. Store bought kimchi will often have sugar in it. I make kimchi at home all the time and you can leave out the sugar when you do it yourself. It is not a necessary ingredient.

One other thing to keep in mind. Products listing microflora count on the packaging. If it’s counted, there is a very good chance it’s added. These are not living, natural probiotics. Most of these products have been heat pasteurized. Which means you are consuming the dead bacteria. The producers then add probiotics back in. 

All Gut Health Studies Say The Same Thing

All of the gut related studies out there suggest the same thing: improper microbial gut balance, affects decision making, mood, skin health, energy levels and creates a tendency to overreact to stress and fear. Bad bacteria will make you unhealthy and can cause you to make poor decisions. When you pair these facts with some other fascinating psychologically based brain studies the picture becomes even clearer.