Have you ever felt butterflies in your stomach? Did you feel an instant pit when something bad was about to happen? Or felt your stomach knot as you were about to get in trouble? These feelings are the result of your gut and your nervous system (which includes your brain) working in tandem, and research has shown that gut health and mental health are closely linked.
What is the gut-brain axis?
Your gut – the main house of your gut microbiome – is lined with nerve cells that constantly communicate with your central nervous system, and vice versa, creating a two-way link between these major bodily systems known as the gut-brain axis.
“Think of the gut-brain axis as a communication highway that connects the two together,” says Nathan Price, PhD, scientific director of Thorne HealthTech and author of The era of scientific well-being. “The gut and the brain are connected in multiple ways. A clear example is serotonin, an important neurotransmitter primarily made in the gut. There have also been recent studies that show that microbes in the gut actually make compounds that travel to the brain and trigger things like hunger cravings for nutrients that gut microbes crave.
Although the scientific and medical communities are still in the early stages of fully understanding the Why And how Behind this link, a large and growing body of research has provided more fascinating insights in recent years. Price says a healthy gut has a big impact on a healthy brain, and it’s become clear that they’re closely linked and often communicate with each other.
“For example, we now know that microbes in the gut make and modulate a variety of key brain neurotransmitters, such as dopamine, glutamate, GABA, and serotonin,” he explains. “The gut microbiome also affects immune signaling and the central nervous system, so the gut can affect both brain function and immune function in the brain.”
In other words, the brain’s emotional and cognitive centers can connect to various parts of your gut and send out good or bad signals (via chemicals called neurotransmitters), depending on your gut health.
The role of inflammation
Inflammation can have a big impact on this relationship. Inflammation is often caused by an imbalance of gut bacteria known as dysbiosis, which can lead to bad bacteria entering the bloodstream. A 2020 review, published in the journal Frontiers in Immunology, suggests dysbiosis also impairs the blood-brain barrier, which can lead to inflammation of brain matter, and these inflammatory pathways have been linked to neuroinflammatory conditions like multiple sclerosis, Alzheimer’s disease, and Parkinson’s disease.
Megan Hilbert, MS, RDN, dietician specializing in gut health nutrition at Top Nutrition Coaching, says this inflammation can come from ultra-processed foods that tend to contribute to a less diverse microbiome. “There are also food additives present in these ultra-processed foods that have been linked to poor gut health outcomes, such as artificial sweeteners and emulsifiers like guar gum, soy lecithin and carrageenan,” says -She.
The Gut Microbiome and Cognitive Health
Research has found several associations between gut microbiome health and brain health, neurological function, behaviors and emotions, including links to Alzheimer’s and Parkinson’s disease. A small study found that patients with Alzheimer’s disease who received probiotic supplementation for 12 weeks showed significant improvements in mental status exams (taken before and after the supplementation period) compared to to a control group.
Certain chemicals metabolized and created by gut bacteria can influence brain function. For example, research reveals that the molecule phosphatidylcholine, which studies have shown is important in helping to ward off dementia, can be transformed into the toxic compound trimethylamine N-oxide (TMAO), if the bad bacteria are present in your gut. People with these bacteria could miss out on its brain benefits, while creating a molecule in TMAO that can negatively affect your heart health. A 2022 study published in Alzheimer’s Research & Therapy found elevated levels of this gut metabolite derived from TMAO microbes in subjects with mild cognitive impairment and Alzheimer’s disease.
The gut microbiome and mental health
A growing number of studies have also begun to show a link between gut health and brain function, behavior and mood, including various mental health disorders such as bipolar disorder, anxiety and depression. A 2021 review published in the journal Pharmacological Research found that in patients who had higher levels of Enterobacteriaceae And Alistip (types of harmful gut bacteria) suffered from depression at higher levels. While those with lower levels of Faecalibacterium (or good bacteria), had lower levels of depression or depressive episodes.
A 2022 study published in the journal Nature Communications examined associations between the composition of gut bacteria and levels of depression symptoms in more than 3,000 people from six ethnic groups, one of the largest cohort studies to examine this. link. After adjusting for factors such as smoking habits and age, the researchers found that “consistent associations between gut microbiota and levels of depressive symptoms were confirmed at multiple levels of analysis,” according to the study, supporting more research on the link between gut health and mood disorders. .
Why is gut health so important?
There are over 40 trillion bacteria in your body, the majority of them living in your gut. Some studies show that there may be over 1,000 species of bacteria in the human gut microbiome alone, and for this reason, your gut microbiome plays an important role in your overall health by helping to control digestion, benefiting your immune system and preventing chronic diseases. .
“Having more diversity in your microbiome is generally associated with better health,” says Price. “Individuals should want to see an abundance of bacteria beneficial to health and a low number of bacteria known to induce disease.” He adds that it’s critical to look at what your gut microbiome is doing metabolically because a lot of the health effects of the microbiome come from compounds it produces or modifies, which eventually show up in your circulation. blood.
Nutrition plays a major role in your overall gut health. Hilbert explains that what we eat is also nourished by these microbes that live inside of us. “The gut is interconnected with many areas of the body,” she said. “Our brain, our skin, our immune system, our hormones can all be affected by the balance of microorganisms living there. These microbes play a role in defending against pathogens, supporting and regulating metabolism and by influencing the absorption of nutrients from food passing through our digestive system.
Simple ways to take care of your gut health
Probiotics and prebiotics
If you’re looking for an easy way to support your gut health, Dr. Price recommends taking a prebiotic and probiotic supplement, but you can also get more prebiotics and probiotics into your gut naturally through certain foods. Probiotics are live, healthy bacteria in your gut. Some fermented foods also contain these microorganisms, adding and replenishing the supply of probiotics in your gut. Some fermented foods containing probiotics include sauerkraut, yogurt, kefir, cottage cheese, kombucha, and miso. PreBiotics are basically a type of indigestible fiber that serve as food for these microbes, helping them to grow and thrive in your gut. Many fruits, vegetables, whole grains, and legumes high in specific types of fiber provide prebiotics to nourish your gut flora, including alliums (garlic, onions, and leeks), asparagus, and apples.
There are also many probiotic and prebiotic supplements available, but it’s always best to consult a healthcare professional when considering adding a new supplement. Eating a diet rich in probiotic and prebiotic foods is always a good start to improving gut health.
Check for food intolerances
Food can be medicine, but for some people, certain foods can actually trigger an imbalance or inflammation in their gut. If you have symptoms like acid reflux, extreme fatigue, gas, nausea, or bloating, you may have a food sensitivity or intolerance. You can try eliminating common trigger foods like dairy, gluten, or caffeine to see if your symptoms go away. If you are unsure how to do this, consult your doctor or a registered dietitian who specializes in gut health. And if you’re unsure which foods are best for improving gut health, Hilbert recommends eating a variety of plant foods and adding more fermented foods to your diet.
Test your gut health
If you’re curious about your gut health, there are a variety of ways to test it. The easiest way is to check your stool after going to the bathroom. If it looks yellow, red, or black, you probably have an infection or your gut is out of balance.
Another indicator could be how often you switch to number two. Everyone is different, but if you notice that you run to the bathroom after every meal or only go a few times a week, it could be a sign to take a closer look at your digestion and look for ways to improve it with help from your doctor. or another specialist.
And finally, testing your gut health through home or office testing is an easy way to get answers straight away. Their price can range from $200 to $600, but speaking with your doctor is a good place to start.