Probiotics, Gut, and Mood


We often laugh about the foolish things the ancients believed. Especially when it comes to medicine.

Balancing biles? Bleeding with leeches? Driving out evil spirits?

It all seems so medieval.

Still, some of our most colorful language comes from those ancient practices—like “biting the bullet” (which you’d do before the days of anesthesia), or saying “I’ve got a gut feeling.”

Turns out, that last one isn’t so silly after all.

Recent research has been pointing to one inescapable conclusion: Your gut is responsible for a large part of your mood.

Or, to be more specific, your gut’s microbiome affects the production of many mood-producing hormones.

Some feelings really do come from your gut.

Today, I’ll show you what we’re discovering about the link between gut microbiomes—the probiotics, or “good bacteria” that live in your gut—and mood.

And then I’ll show you how you can have the healthiest, cleanest microbiome around. And why that might brighten your days more than anything else.

Importance Of Gut Health

You know that feeling of butterflies in your stomach before an important event?

You aren’t just imagining it.

It turns out, there is an entire network of neurons that line your gut. 100 million in total—more than you’d find in your spinal cord.

There are so many neurons that some scientists call this network your “second brain.”

Now, let’s be clear—there isn’t any conscious thought going on here. When you are contemplating the works of Descartes, your intestines aren’t chiming in.

Rather, this network of neurons is responsible for all the mechanics of digestion. From squeezing food down the esophagus, to extracting nutrients in the intestine, this neural network is doing the work independent of your brain.

But that’s not all. Your second brain also produces the vast majority of your body’s serotonin.

Also known as the “feel good” neurotransmitter in your brain, interestingly enough 80%-90% of your serotonin is made and found in your gut.

Serotonin is extremely important for instructing muscles to constrict, carrying impulses between nerves, regulating cyclic processes within the body, and regulating mood as well.

In addition to serotonin, the bacteria that make up your microbiome produce their own set of important, influential chemicals.

In a very real way, your gut is more responsible for your feelings than your head.

Seems like ancient beliefs about “gut feelings” were onto something.

How bacteria change your mood

However, one thing that the ancients didn’t understand is the microbiome.

Even today, the interaction between your body and the bacteria that call it home aren’t all that well understood. In many ways, we’re still in the dark. We don’t understand how the interactions take place.

But one thing we know for sure: Interactions are happening. Your microbiome is influencing the neurons in your gut, the production of serotonin, and your mood.

In lab tests, we’ve been able to influence the mood and behavior of animals just by replacing their microbiomes.

For instance, we can give a shy mouse the microbiome of an adventurous one—and it will become bolder and more adventurous. Or vice versa.

We can give a normal rat the microbiome from an obese one, and the rat will immediately start to act like an obese one.

There is even a tentative theory that a malfunctioning microbiome is responsible for autism in children—explaining why autistic children often also have gastrointestinal problems.

How To Have a Healthy Gut

The next few years will see a flowering of research in this new field, and I’m expecting a number of breakthroughs.

We may discover that a malfunctioning microbiome is responsible for a whole host of psychological and physiological diseases, from autism to depression to who knows what else.

In extreme cases, we may start treating some of these diseases with microbiome replacement—basically, cleaning out the old bacteria and putting healthy samples in their place.

But there’s a simpler way to achieve the same thing, and to do it starting today.

You see, in many ways, you’re responsible for your own microbiome. What you feed yourself has a huge influence on what bacteria thrive.

And we know exactly what good bacteria like.

So follow this simple three-step plan, and your microbiome will be in great shape:

  1. Eat prebiotics. Prebiotics are basically the favorite food of bacteria.

But it goes beyond simply feeding the bacteria. Your food isn’t just their food—it’s also their entire environment.

So you need to give them the best possible environment in which to thrive.

Luckily, we know exactly what that means. Fiber—and lots of it.

Foods rich in fiber—like fruits and vegetables—make for a very healthy microbiome.

Unsurprisingly, they make for a very healthy human as well.

So make an effort to increase your fiber uptake, starting today.

  1. Take probiotics. Probiotics are the healthy, good bacteria you want in your gut.

Once you’ve made the perfect habitat for them—by eating lots and lots of fiber—make sure to put the good bacteria in there.

Like it or not, your gut is always full of bacteria. But sometimes unwanted guests are part of the mix.

By taking a quality probiotic supplement, you’re giving beneficial bacteria the best chance of thriving.

  1. Don’t kill the little ones. The easiest way to mess up a microbiome is by wiping out your current one.

And that’s very easy to do.

If you take antibiotics, those medicines don’t just kill infections—they kill all bacteria. Avoid antibiotics except in cases of true need.

Likewise, avoid eating anything caustic or toxic. That sounds simple enough—but remember, most of your processed food contains preservatives that can do plenty of harm to the bacteria of a microbiome.

Bottom line—eat as many healthy, whole foods as possible. Avoid artificial preservatives and additives. And keep a steady flow of healthy bacteria heading towards your gut.

Today, the best science indicates this will do more than help your digestion and health. It may also directly lift your mood, as well.



Last Updated: June 22, 2021
Originally Published: 
February 29, 2016