You Are What You Eat: The Gut Microbiome and Your Brain

Forget the greasy food/greasy skin analogy. “You are what you eat” rings far closer to the truth when it comes to the intestinal microbiota (aka “gut bacteria”). Did you know that most of the cells in our body belong to bacteria?! And did you know that we create this bacteria through the foods that we eat, and that the resulting gut microbiome is intrinsically linked to your brain? Let’s discuss!

Meet your Microbiome

Your gut is a thriving little ecosystem, home to millions of bacteria that we create from what we eat. That’s why probiotics and prebiotics are so good for you—they promote the growth of beneficial bacteria in your gut. And nourishing that bacteria is key, because it affects *everything.* Our gut bacteria influences our immune system, long-term disease risk, weight, and the brain. If you’ve ever experienced butterflies when you’re nervous—that telltale tingle in your stomach—then you’re already familiar with the gut-brain axis in real time.

The research is still ongoing, but we do know there are millions and millions of neurons in the gut that are in regular communication with the brain, via a two-way connection that involves everything from hormones to the immune and nervous systems. It’s such a big deal, in fact, that the gut has its own little nickname—the second brain.

Learning Alllll About the Gut-Brain Axis

A team working on intestinal bacteria transplants in mice illustrates the gut-brain axis nicely.

They transplanted gut microbiota between different strains of mice and showed that behavioral traits specific to one strain transmitted along with the microbiota. So, for instance, shy mice would exhibit more outgoing behavior when carrying the bacteria of more adventurous mice. There was a significant difference in behavior of mice based on their gut bacteria. 

Unpublished research also suggests that taking fecal bacteria from humans with both IBS and anxiety and transplanting it into mice induces anxiety-like behavior, whereas transplanting bacteria from healthy control humans does not. This is crazy cool! 

Researchers are starting to discover ways that bacteria in the gut might be able to get their signals all the way up to the brain. Some have shown that in mice, microbial metabolites influence the basic physiology of the blood–brain barrier (basically, the big locked "gate" to the brain). Gut bacteria breaks down complex carbohydrates into short-chain fatty acids with a bunch of effects, including the fatty acid butyrate, which fortifies the blood–brain barrier by tightening connections between cells.

How the Second Brain Affects the First Brain

The effects of the gut bacteria on the brain can be summed up in three very basic categories: 

1. Serotonin. Bacteria in the gut produce serotonin, one of the 'happiness' neurotransmitters. 

2. Immune system. Bacteria in the gut can stimulate the immune system to make cytokines that influence neurophysiology (the way the brain functions).

3. Molecules produced. Some of the molecules made by bacteria (i.e. butyrate) may change the actions of cells in the blood-brain barrier. 

So, why should this matter to you?

Researchers are still learning all the ways the gut and brain communicate, but it’s opening doors to all kinds of fascinating new ideas and possibilities. But for you, right this minute, it means you should prioritize keeping the bacteria in your gut healthy and happy, just as you do the rest of your body. 

That means probiotics and fiber, and you know what that means… a freezer full of Bumpin Blends smoothies! You’ll find fiber in each and every one of our smoothies, so you really can’t go wrong with your choice of flavor. And bonus—a variety of fiber sources can keep your gut microbiome flourishing, so, you know, mix it up! Shoot for a different Bumpin Blends smoothie every day. Your first and second brains will thank you.