The Mind-Gut Connection

The Mind-Gut Connection featured in upcoming Lunchtime Learning Presentation

The more I learn about the human body and the world, the more obvious it becomes that every little supposedly insignificant thing matters and everything is inextricably connected. The bad news is there is no cheating your way to health or fitness or happiness. But the good news is, although it may seem harder, the tried and true methods of slowly achieving success are always available to us. If we treat both our bodies and our minds well and show them patience and compassion, health and happiness with inevitably follow. A lot of people will find this obvious and uninteresting, but I’ve never been one to base any of my opinions or actions on good faith alone, I usually require a more thorough knowledge of the mechanisms going on behind the scenes.

The emerging science of what’s going on backstage in our own bodies is truly stranger than fiction. Most of us know (although we don’t like to think about it) that our bodies contain lots of microscopic organisms in addition to our human cells. Our skin, our hair, our nails, our eyelashes, and of course our guts are teeming with strange little lifeforms, the majority of which are harmless. It may be a bit unsettling to consider, but the bacteria inhabiting our bodies are actually even more than harmless, they are helpful, even necessary for us to be healthy. Before reading The Mind-Gut Connection by Dr. Emeran Mayer, I thought my vague comprehension of that fact was sufficient. Gut microbes are good for us, case closed. Now I’m discovering that the role these little organisms play in our digestion, day to day life, decision making, and ever our personalities are far more complicated than I’d ever imagined.

Apart from all the implications this information sparks curiosity about in the scientific community, my philosophy centered mind goes straight for the larger existential questions we are now faced with. Who is really running the show? Are we this human form shown to the world, or are we actually the bacteria pulling the strings deep inside our guts? Perhaps we’re just the passive hosts without even realizing it. Or maybe it’s not even possible to make a clear distinction between the human and bacteria cells within us. For now it does appear as if we are one in the same.

Whatever we may be, Dr. Mayer’s book is an excellent example of the way looking deeper into the natural world leads only to more marvel and mystery. The complexity and intricacies of this existence are an endless source of fascination that I don’t think we’ll ever truly be able to decode. However, we have now learned at least a bit more about this magical little world within us. So here are a few of what I found to be the most interesting things laid out in this book:

Personality & Decision making

These bacteria in our digestive organs do a lot more than help us break down our food. They are also influencing our mood, disposition, and the decisions “we” make. We all know that our cells communicate and deliver signals and chemicals to the brain, but what I didn’t know was that these bacteria are doing the same. I was shocked to discover that our gut produces the majority of serotonin in our bodies, not the brain. This is one of the reasons we experience that familiar cozy, satisfied feeling after a good meal. This also explains the way our diet affects our mental health. It’s not just a placebo effect. Eating healthy, fibrous, fresh, unprocessed foods really does make us feel better all around.

One of the most incredible things I learned was from a study that showed transplanting the gut microbiome of one rat into the gut of another causes the latter rat to begin expressing a personality and behaviors more similar to the donor rat. For instance, a shy rat given the microbiome of an outgoing rat, will now begin to appear brave. It’s honestly a bit frustrating to realize what a big role the gut microbiome plays in our mental state. Perhaps one of the reasons I’ve faired so well without my paxil is because I’ve been drinking pro & pre-biotics every day since before I began weaning myself off the drug. It makes me wonder what kind of success, if any, I may have had in my battle with social anxiety if I had known this information before starting an SSRI.

Hunger, Satiety, & Weight

The microbes in our guts also have a big part to play when it comes to our appetite. They have a direct line to our brains with the capacity to influence our hunger signals. What I once thought was a definitive sign that my body needed more calories or nutrients, now may very well just mean that my gut bacteria need more fibrous matter and pre-biotics to snack on. These little buddies also have a hand in our sensitivity to our satiety signals, in other words our cue that we are full and want to stop eating. These bacteria are also responsible for how much of the food we eat is absorbed and stored in our bodies.

Just as in the other rat study I mentioned, the same effect can be observed regarding the physical weight of the rats. Give a skinny rat the microbiome of a heavy rat and it will begin to gain weight and vice versa. This is a stunning insight into just how little we actually comprehend about nutrition and how to influence our own body weight. There really is no “one size fits all” diet when it comes to weight loss or gain, and it’s got a lot more to it than just genetics.

The Best Diet for a Healthy Gut Microbiome

This book also gives suggestions about the best foods for us to eat if we want a gut microbiome that keeps us healthy and happy. The author particularly emphasizes that diets high in animal fat lead to a state of constant inflammation and physical and mental health complications. Not surprising. He also says that diets high in fibrous plant foods lead to more helpful strains of bacteria flourishing in our guts. Now it seems obvious to me that the extrapolation of that information points directly to a vegan diet. No animal fat, tons of plant foods. However, this author is clearly attached to his flesh foods, because based on anecdotal evidence of healthy tribal peoples who eat a mediterranean diet (basically vegan, plus fish) he decided to label that the best diet. He gives no explanation on how the fish part is necessary or beneficial. The actual data he provides seems to say the opposite. So I think it’s safe to say eliminating the last “bad gut” food, would be best, don’t you think?

Unfortunately, he goes on to say that even a drastic change in diet isn’t going to have a huge effect on the types of bacteria living in our guts. However, it will change the kinds of metabolites the bacteria we already have produce for our bodies and brains, which is nearly as good.


In summation, the information I’ve learned from this book has completely changed the way I view my body and even my mind. I fluctuate back and forth between being excited and terrified about this new knowledge and what it means. At the very least, this book shows just how important our physical health is when it comes to our mental health. The two are inextricably linked for better or worse. Really all we can do is work with the gut-microbiome we have. They are as unique and diverse as each individual they are house in. Treat them right, give them lots of healthy vegan foods to eat, and they will repay us in kind.