Maintaining a healthy, functioning digestive tract, is truly one of the keys to overall health and wellness. Everything from your immune system, to hormone production, to your brain is connected to your gut, explains Lauren Antonucci, M.S., R.D., owner, and director of Nutrition Energy. “Research is increasingly showing that the microbiota that live in your digestive tract not only play an important role in maintaining the health of your digestive tract but also in other far-reaching systems throughout your body,” she says. One of those involves regulation of our emotions and our feelings. Yep, that whole saying “you are what you eat,” is starting to make a bit more sense now. Here, nutrition and health experts help us understand the gut-brain connection.
Inflammation in your brain can make you depressed.
As Dr. Vincent M. Pedre, M.D., an internist and functional medicine practitioner in New York City, puts it, “A brain on fire is a depressed brain.” This means the brain is inflamed as a result of a leaky blood-brain barrier, which results from a leaky gut.
“The blood-brain barrier is designed to protect the brain from toxic substances that enter our circulation and may have been absorbed through the digestive system, airways, or skin,” Dr. Pedre explains. “When the blood-brain barrier becomes leaky due to inflammation, it leads to brain inflammation. If your brain is inflamed, it will alter signaling in the brain that affects the production of neurotransmitters (like the ‘happy’ neurotransmitter serotonin) and result in depression.” It may feel like the depression is mental, but, according to Dr. Pedre, it’s actually being powered by this brain inflammation that actually originated in the gut.
Your gut impacts your hormones, which affect your mood.
The microbiome is a key player in maintaining proper hormone balance. “If your gut is out of balance, you lose 20 percent of thyroid hormone activation,” says Dr. Pedre. “Less activated thyroid hormone means slower metabolism, fatigue, and possibly hair loss. This may lead to the recirculation of the female sex hormone estrogen. Recirculating estrogen that’s been metabolized and excreted for elimination in your bowel movements leads to estrogen dominance.” If you’ve ever experienced bloat (aka water retention), tender breasts before your period, heavier or irregular periods, increased cramping, and increased moodiness leading up to and during your monthly cycle, this is what he’s referencing. “For a more balanced emotional state, you need a balanced gut flora,” he adds.
The stress hormone cortisol can end up in our gut.
Too much cortisol, aka the stress hormone, in the gut can cause certain types of bacteria to grow,” explains Dr. Marc Milstein, Ph.D., a biological chemist who specializes in the gut-brain connection. “Basically, stress can determine which types of bacteria grow in the intestine. The types of bacteria that thrive in high-cortisol gut environments can make anxiety and stress worse,” he says. In other words, stress can lead to more stress through the gut-brain connection. “This means that when we treat mood issues, we must consider the gut. When we treat gut issues, we need to consider our mood and brain,” he adds.
Your gut produces most of the “feel-good” chemicals in your body.
Dr. Pedre explains that the gut produces 90 percent of the body’s serotonin (that “happiness” chemical). When there’s an imbalance of good and bad bacteria in the gut, also known as dysbiosis, the gut becomes inflamed. This leads to an increase in intestinal permeability. While depression is one result, as we mentioned previously, another is unregulated anxiety. To increase serotonin production, Dr. Pedre recommends following a gut-healing plan, like his Happy Gut 28-day cleanse. He also advises incorporating meditation into your day-to-day routine to help balance the gut microbiome and mental health.
Without GABA, anxiety bubbles up.
GABA, or gamma-aminobutyric acid, is an important neurotransmitter that is responsible for regulating the feeling of anxiety in the body by “shushing” an overactive nervous system, explains Dr. Pedre. “Without GABA, anxiety significantly increases and the sufferer often doesn’t realize where it really is coming from,” he says. One recent study published in the Journal of Translational Medicine analyzed anxious individuals and found that those who drank lactobacillus and Bifidobacterium bacteria every day experienced lowered anxiety scores after 12 weeks.
Your gut can reduce cravings for sugar and junk food.
The type of bacteria living in your digestive tract depends on your diet, explains Sarah Morgan, M.S., a functional nutrition expert. “If you eat whole foods grown by Mother Nature, you will feed the good buddies in your belly. If you eat lots of processed foods, high in sugar and toxic fats and low in fiber, you will feed the bad germs in your belly,” she says. These bad germs can take over the scene in your digestive tract. They can also cause you to crave sugar and junk food. We all know what happens when we crash after eating a pile of candy: we physically feel terrible! “Over time this can lead to weight gain, mood disruption, low energy, and more,” Morgan explains.
How to Improve Your Gut Health
In additional to eating a healthy and balanced diet, and exercising regularly, most experts recommend taking a probiotic. “As more specifics are learned about which probiotic strains affect which conditions, the more we can customize our recommendations to each individual. But for now, it may be wise for many of us to be taking a daily probiotic supplement—certainly for anyone interested in improving their digestion, boosting immunity, or improving mood,” says Antonucci.