“Stress poops”, “nervous butterflies”, and “anxiety burps” have long clued people into the possibility that the gut and brain are intertwined. In recent years, though, research on this relationship has proved that the gut-brain connection isn’t just anecdotal, but something with real science behind it. “A growing body of research shows how our physical health and mental health are inextricably linked,” says lifestyle medicine physician Onikepe Adegbola, M.D., Ph.D., founder of the virtual IBS clinic Casa de Sante. But how are the gut and mind linked, exactly—and what can you do to support both? Find out below.
The Gut-Brain Connection, Explained
In order to understand the gut-brain connection, you first need to understand the biology of the gut. The gut contains trillions of microorganisms, primarily bacteria, which is collectively referred to as the gut microbiome, explains Adegbola.
When operating optimally, the collection of bacteria in your gut works to help regulate your digestion and metabolism, Adegbola says. “These bacteria also produce short-chain fatty acids, neurotransmitters, and hormones that can influence mood and cognition,” she explains. In fact, research shows that dopamine, norepinephrine, serotonin, and gamma-aminobutyric acid (GABA), reside in the gut as well as in the brain. For this reason, the gut is sometimes known as “the second brain.”
That said, in order for the gut to operate optimally, the gut microbiome has to have the proper balance of what are referred to as ‘good’ and ‘bad’ bacteria, says Adegbola. An imbalance in these microbiome bacteria can lead to inflammation in the gut, which can then impact the gut’s ability to produce the proper amounts of each neurotransmitter. “In turn, this can negatively impact an individual’s mental health,” she explains.
Indeed, one 2020 study published in Cureus found that people with depression often have lower levels of certain bacteria in their gut compared to those without depression. Meanwhile, another published in Advances in Nutrition suggests that changes in diet that alter the composition of the microbiome can effectively improve symptoms of anxiety and depression.
In short, “the data suggests that what is going on inside our gut may have profound implications for our mental health well-being,” says Adegbola.
5 Things You Can Do To Support Gut (And Mental) Health
Given that poor gut health can contribute to mental unrest, you probably want to know what you can do to support your gut microbiome. Here are five foundational things you can do to support your gut microbiome and ultimately promote mental well-being.
1. Limit Highly Processed Foods
At grocery stores and convenience shops, processed foods are more readily available than fresh produce. But highly-processed foods are hard on gut health.
The gut microbiome is nourished by fiber, water, collagen-rich proteins, and vitamins and minerals, explains Adegbola. Meanwhile, it’s negatively impacted by refined sugars, trans and other unhealthy fats, artificial flavors, and preservatives, which are all present in high quantities in highly processed foods. As such, “a diet high in processed foods can disrupt the balance of beneficial bacteria in the gut,” she says.
How it happens: Highly-processed foods cause inflammation to the gut lining, which then inhibits the growth of ‘good’ bacteria, Adegbola explains. Over time, this can throw off the balance between ‘good’ and ‘bad’ bacteria, and lead to unfavorable gastrointestinal—as well as mental—symptoms.
Your move: Limit your intake of refined sugars and highly processed foods as much as possible. “Replace these highly-processed, high-sugar foods with a rainbow of fruits and veggies,” says licensed therapist and nutritional therapy practitioner Alexandra McNulty, L.C.S.W.-C., B.C.H.N., N.T.P., founder of McNulty Psychotherapy and Integrative Wellness. Plants get their different colors from different phytonutrients, all of which have antioxidant and anti-inflammatory properties that can help reduce gut inflammation, she says. “If you’re craving sweetness, opt for natural sources of it, like fruit, which provides essential vitamins and minerals as well as fiber for healthy digestion,” Adegbola suggests.
2. Watch Your OTC Drug Use
Food, of course, is not the only thing you ingest. Oral supplements, over-the-counter drugs, and prescription medications also all make their way through your digestive tract and thus have the power to alter your gut microbiome. “Nonsteroidal anti-inflammatory drugs (NSAID), in particular, are medications that have been shown to impact gut health,” says Adegbola. So if you pop NSAIDs (think ibuprofen and acetaminophen) without a second thought, well, give that a second thought.
Indeed, one 2017 study published in the journal Clinical Microbiology and Infection found that the NSAIDs an individual ingests can impact the bacterial composition in their guts, for the worse. Further, research published in Frontiers in Pharmacology shows that frequent use of NSAIDs can create gastrointestinal toxicity (defined as a suboptimal gut bacterial balance) that can lead to nausea, indigestion, constipation, diarrhea, abdominal pain, and, in extreme cases, gastroduodenal ulcers.
So what should you do? Be mindful of how frequently you take these OTCs and why. If you regularly rely on NSAIDs, consider talking to a healthcare provider. Ideally, they’ll be able to help you figure out the root cause of your pain, so that you can eliminate it, your reliance on NSAIDs, and the negative effects that come with these common drugs.
3. Take Antibiotics Cautiously
Generally speaking, people take NSAIDs far more frequently than they take a course of antibiotics. After all, antibiotics can’t be purchased over the counter; they’re prescription medications used to treat bacterial infections. Yet while antibiotics are designed to do the job of killing off ‘bad’ bacteria, they can also kill off ‘good’ bacteria while they’re at it, explains McNulty. “In turn, this can lead to an imbalance of ‘good versus bad’ bacteria in the gut,” she says.
In one 2016 study published in the journal Genome Medicine, researchers concluded that antibiotics can cause lasting side effects on the gut microbiome. A second 2022 study published in MicrobiologyOpen noted that antibiotics can decrease microbial diversity, change how the gut microbiome functions, and even increase an individual’s risk of developing antibiotic-resistant infections in the future.
In response to research about the potentially damaging side effects of antibiotic use, healthcare providers as a whole are reevaluating how they utilize antibiotics—and how they can better support people who need to take them. For instance, researchers now suggest that phage therapy (the use of bacterial viruses to treat bacterial infections), incorporating probiotics alongside antibiotics, and fecal microbiota transplants following antibiotic disruption can be used in place of straight-up antibiotic use.
First, know that antibiotics are not effective for treating viruses, such as colds and many sinus and ear infections. No solid healthcare provider should prescribe antibiotics willy-nilly. (The CDC reports that 28 percent of the antibiotics prescribed each year are unnecessary.) If you have a bacterial infection that your provider plans to treat with antibiotics, it may be worth bringing up these research-backed alternatives with them. Just keep in mind that certain infections—like strep throat—can only be treated with antibiotics. In these instances, refusing antibiotic treatment could put your overall health at risk, which ultimately won’t help your gut health or mental well-being.
4. Supplement With Probiotics and Prebiotics
Two supplements you can turn to for gut health support? Probiotics and prebiotics. “Probiotics and prebiotics can be a saving grace for an individual’s gut health and therefore their mental well-being, too,” Adegbola says.
Quick refresher: Probiotics are the live, good-for-you bacteria and yeasts that live in the gut. Prebiotics, meanwhile, are the indigestible fibers that function as food for the good bacteria (probiotics) in our gut.
In one study published in the journal Frontiers in Cellular and Infection Microbiology, probiotic supplementation helped to effectively replete ‘good’ gut bacteria that had been wiped out. A second study published in Translational Psychiatry, meanwhile, looked directly at the impact of probiotic supplementation on mental wellness following stress, and found that by supporting the gut lining, probiotics may have the power to help the body and mind manage mental distress.
When shopping for probiotics and prebiotics, Adegbola recommends opting for a two-in-one option. “Supplements that are both a prebiotic and a probiotic provide the important bacteria, as well as the fuel that good bacteria needs to work efficiently,” she explains. That said, while probiotic and prebiotic supplementation may be beneficial, they should not be used as a replacement for professional medical advice or treatment.
5. Manage Stress Levels
If you’ve ever been the victim of stress poops, the colloquial term for the lavatory lava that can accompany anxiety-inducing events or encounters, you’re familiar with the ways stress can impact the gut.
“When you experience stress, your body produces a hormone called cortisol,” explains Adegbola. And when the body releases high levels of this stress hormone, it directs all of its energy towards getting you out of whatever stressful situation you’re in, she explains. As a result, blood and oxygen flow to the digestive tract decreases, which can interfere with digestion and cause symptoms such as abdominal cramping and pain, as well as sudden, ahem, evacuation.
High levels of cortisol also decrease the production of the mucus that coats the digestive tract to support nutrient absorption (and prevent undesirable particles from crossing that barrier). This contributes to intestinal permeability, making it possible for partially-digested substances to access portions of the tract they shouldn’t and cause inflammation, explains McNulty. This inflammation can then lead to an imbalance of bacteria in the gut.
Thankfully, there are a wide variety of practices individuals can incorporate into their daily routine to reduce stress levels and help stop excess cortisol from upsetting the integrity of their gut, says McNulty. These practices can include, but are not limited to: meditating, gratitude journaling, grounding, walking outside, taking dedicated time off from technology, and practicing mindfulness.