Let me give you a personal example.
When I lived in Arizona in my early 20s, I spent the better part of a year in a dull fog. At that time in my life, I hadn’t started meditating. I had no skill in relating to my emotions. And so the dull fog remained indistinct for months on end.
But when my girlfriend dumped me one scorching summer day, I began to suspect something was wrong. Was it my unsexy clothes? No. Absolutely not.
Okay fine. Maybe they didn’t help. But what really was wrong was my mood. It hadn’t been right in what seemed like forever.
Incredibly enough, the cause of my bad mood was right there on the surface; I’d just been denying it. The cause was something called “leaky gut”. When I moved to Arizona, I’d brought my weak stomach with me. And my gut had made happiness hard to find.
But before we get to the mood connection, let me explain leaky gut first. This will be important later.
When the gut becomes leaky…
First, something needs to make the gut leaky. There are many potential culprits: bacterial overgrowth, antibiotics, environmental toxins, parasites, fungal infections, alcohol, and so on. In my case, it was a combination of a stomach virus and several courses of antibiotics.
The intestinal wall is only 1 cell thick, so it doesn’t take much to compromise this barrier. It’s not exactly Fort Knox down there.
When the gut barrier becomes compromised, undigested food starts to slip into the bloodstream. That’s not supposed to happen. And so, confused by these strange objects in the blood, the immune system attacks. (Stupid immune system!).
As part of the immune response, a bunch of chemicals called cytokines are released into the body. While some cytokines are necessary for normal immune function, too many of these “inflammatory cytokines” are actually quite harmful. If you’ve heard bad things about inflammation, you’ve heard bad things about cytokines.
Inflammation and depression
How does this affect mood? Inflammatory cytokines, now filling the bloodstream, make their way to the brain. And this makes the brain sad.
“The most current theory on what causes depression,” reports functional medicine clinician Chris Kresser, “is called the inflammatory cytokine model of depression. [This model] holds that inflammation, whether it starts in the gut or somewhere else in the body, suppresses the activity of the frontal cortex and causes all the telltale signs of depression.”
There’s plenty of research to support this claim. When inflammation is there, depression is usually there too. In terms of gut inflammation, this looks like: leaky gut <–> inflammation <–> negative emotion. Notice how the arrows go both ways.
The most direct evidence of inflammation causing depression comes from a study I would never sign up for. In the experiment, 20 men were injected with either Salmonella endotoxin or saline solution. (Yeah, Salmonella.) The Salmonella groups, as expected, showed increased levels of inflammatory cytokines in response to being poisoned. The interesting part? These groups also showed symptoms of anxiety and depression. Hopefully they got more than a slap on the back for participating.
Building a happy gut
So what can you do to build a happy gut without all that inflammation? For starters: exercise, stress reduction, sleep, micronutrients, healthy fats, fiber, sunlight, and blah blah blah. I could go on for pages.
But I’ll stick with 3 for now:
1) Probiotics: Probiotics, specifically the lactobacillus and bifidobacterium strains, lower stress and decrease anxiety in both mice and humans. Pro tip: fermented foods like sauerkraut are rich in both of these strains and won’t bankrupt you like store-bought probiotics.
2) Prebiotics: Mice in this study had significantly less stress after just 3 weeks of prebiotics, which are food for good bacteria. Fructans, inulin, and galacto-oligosaccharides are some of the major ones. You find prebiotics in onions, asparagus, garlic, bananas, and many other fruits and veggies.
3) Meditation: An unhealthy gut makes you stressed. We covered that. But it’s also true that too much stress makes your gut unhealthy. In this study, researchers measured the effect of Mindfulness Based Stress Reduction (MBSR) – Jon Kabat Zinn’s famous meditation program – on inflammation. At the end of the study, the MBSR group had lower levels of cytokines. To learn more about meditation, check out my articles here, here and here.
The key to happiness?
Once I made healing my gut a priority, things started to turn around for me. It didn’t happen overnight. But one day, I noticed that my baseline mood had risen considerably.
Not that I suddenly became Jolly McJollerson. If you asked a close friend to describe me, and they settled on the word “jolly”… I would pause to inquire what substance my friend might have recently ingested. Had they had enough sleep? Were they okay? Really: were they okay? I could call for help.
So no, fixing my gut did not fundamentally change my character. But it did make it easier for happiness to find me.