Feeling Meh? This Is How Your Gut Affects Your Mood (Plus, Exactly How To Fix It)

"Most days are just full-blown blah," 34-year-old Michael told his doctor during an initial consultation. "Even life’s simple pleasures no longer make me happy. The other day I watched an amazing impersonator at Washington Square Park and… Usually, that sort of thing makes me smile. But…nothing. That’s how I knew I was unhappy."

While Michael’s former physician wanted to put him on an antidepressant, he insisted he wasn’t actually depressed but rather in a miserable, seemingly never-ending funk.

Whether you feel anxiety, depression, or just that all-too-common blah feeling, mood disorders often start in the gut. In this case, the gut-brain connection becomes more important than you might think.

Whereas doctors may brush off Michael’s symptoms as something to medicate away, there’s another way to look at this if you think of the gut. Even a slightly off-kilter mood can affect work performance, relationships, and just about everything else in life.

Instead of starting with brain health, the evolving new paradigm of functional medicine says start with your gut.

Let’s back up here. Michael’s former doctor had him on antibiotics for a minor infection. Along with a high-sugar processed diet, he owned a house in upstate New York that happened to be near an apple orchard. He was on two medications for high blood pressure. And his labs showed incredibly high levels of C-reactive protein (CRP), a marker of inflammation.

In fact, antibiotics are the biggest culprit for dysbiosis, but other things like chronic stress and environmental stressors (e.g., pesticides) also contribute. For Michael, those conditions led to leaky gut, which further affected numerous symptoms including brain fog and that blah feeling.

To understand why a gut imbalance (like dysbiosis) triggers problems like leaky gut and affects your mood, remember your gut’s inner lining is very thin, only one cell-layer thick, in fact. When that layer becomes compromised by stress and antibiotics, inflammation rapidly spreads from your gut through the rest of your body. Basically, a gut on fire is a brain on fire. Brain inflammation then leads to what people feel as depression.

For Michael, that meant he wasn’t digesting or absorbing the paltry amount of nutrients from his poor diet. Toxins, foreign material, infectious organisms, and partially digested food particles leaked into his bloodstream and traveled to the barrier between the brain’s special circulation and the rest of your body.

We call that barrier your blood-brain barrier (BBB). When you have a "leaky" gut, you also have a leaky brain. In other words, inflammation in your gut triggers inflammation in your brain.

Michael was also low in serotonin, a "happy mood" neurotransmitter. Your gut’s microbiome produces more serotonin than your brain, and about 95 percent of serotonin receptors are found in the gut itself. Along with about 30 other neurotransmitters, you can begin to see how your gut becomes central to feeling happy.

When you balance your gut with the right proportions of healthy "probiotic" bacteria, you create a happy brain as well. Disturb that balance and allow the wrong bacteria and yeast to take over, and guess where their inflammatory metabolites and signals reach? Yep, they cross the BBB, stunning the brain and creating behavioral and emotional problems. With the bugs producing these toxins, your brain simply can’t function.

Throw in your immune system’s response (about 70 percent of your immune system lies in your gut), which includes the secretion of all sorts of inflammatory signals that also affect your brain, and you become chronically inflamed, leading to depression, erratic behavior, and even memory problems. High stress alone will affect your ability to retain memories.

Simply put, you cannot work effectively on your brain health if you don’t create an environment that reduces brain inflammation. Your brain functions best when its signals are not jammed by toxins, food allergens, dysbiosis, nutritional deficiencies, and stress.