This kind of bacteria can impact your mental health more than you think.
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Is it just us or is the topic of gut health being talked about by everyone lately? It feels like people on social media or experts in digital publications are discussing the importance of the gut and why you need a healthy one to live a healthy life. There's even a #guttok on TikTok with millions of videos. So if the talk of gut health has made its way onto Gen Zer's territory, then you know it's, dare we say, trendy. But what the hell is the gut, and why does it matter, anyway?

As it turns out, the gut is responsible for many functions in the body including, digestion and even your mental health. Have you ever heard of the brain-gut connection? Well, studies show that having a healthy gut can reduce depression and anxiety. If you're wondering how, keep reading because we're breaking down everything you need to know about your gut, including what it is, how it functions, and how it's connected to your mental wellbeing.

What is your gut?

The gut, or gastrointestinal tract, consists of your digestive system and includes the mouth, esophagus, small and large intestine, liver, pancreas, gallbladder, and anus. The role of this system is to break down food, extract nutrition, and eliminate any waste, registered dietician Chelsea McCallum, tells HelloGiggles.

When you hear people talking about the gut, they're specifically addressing the lower intestine, which is the home to thousands of good and bad bacteria. "When talking about the gut, we're generally referring to the gut microbiome, which consists of all the microorganisms (aka bacteria) that live primarily in our lower intestine," says Lauren Kelly, registered dietician and vice president of social and partnerships at Sound, a sparkling water company that's made with tea and botanicals.

But while your microbiome contains a healthy mix of good and bad bacteria, factors like stress and diet can cause a change in gut bacteria and create a ripple effect that leads to negative mental health concerns, writes Uma Naidoo M.D., nutritional psychiatrist, in her book This Is Your Brain on Food. If you're wondering how this happens, it's because of the connection between the brain and your gut.

What is the connection between your brain and gut?

It may seem like your brain and gut have nothing to do with one another because they're on nearly completely opposite sides of the body, right? Well, they're actually very connected through something called the vagus nerve. Studies show that the vagus nerve controls many bodily functions like your mood, immune response, heart rate, and, you guessed it, digestion. Its key function is to ensure that nerve signals can send information back and forth between the gut and brain.

The easiest way to think about how the brain and gut interact with one other is by thinking of how headache medicine provides relief for pain. When you swallow a pill, it makes its way into the gut and gets broken down. Then the chemicals released from within that pill travel from your gut to your brain to reduce inflammation and subside your headache. "In the same way as the chemicals in that pill [are produced], chemicals created by the gut can also reach your brain, and chemicals produced by your brain can reach your gut," writes Naidoo in her book. And the kind of chemicals that are being produced in your brain (and your gut!) are mood-regulating neurotransmitters, such as dopamine and serotonin, which are responsible for stabilizing mood and regulating sleep. In fact, 90% of serotonin receptors are found in the gut, says New York City-based neuropsychologist, Dr. Sanaam Hafeez.

So, what does this mean? It means your gut has way more of an influence on your mental health than most people actually think. "The primary reason gut bacteria have such a profound effect on mental health is that they are responsible for making many of the brain chemicals," Naidoo writes in her book. If the bacteria in your gut get disrupted, then the production of these mood-boosting chemicals, like dopamine and serotonin, get affected and can have a direct impact on your mental health.

Because your mind and gut are a two-way street, that means the foods we eat can positively (and negatively) affect our mental state. "The lack of quality food to keep those healthy bacteria thriving seems to impact our mental health, primarily in the form of increased risk of depression," says Kelly, which leads us to our next question.

What foods can help promote better mental health?

2019 survey done by Mireia Valles-Colomer looked at the relationship between the microbiome and depression in over a thousand people. She found lower levels of healthy gut bacteria in people with depression, even after using antidepressants, and those with improved mental health showed an increase in dopamine metabolite in the microbiome, which helps promote the growth of healthy gut bacteria.

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So, if an unhealthy gut leads to an unhealthy mind, how do you promote a healthy gut? It all starts with your diet because different foods can change the bacteria present in your gut microbiome. "Fruits, vegetables, grains, nuts, seeds, herbs, and spices all play a role in a healthy gut," says McCallum. A 2016 study found that increased intake of whole foods, like fruits and vegetables, was associated with greater happiness and life satisfaction because of the vitamins and minerals they have. 

Probiotic and prebiotic-rich foods also support a healthy gut and can even help with gut-induced depression. "Think fermented foods, like kimchi, miso, sauerkraut, pickled veggies, a quality yogurt, or Kefir," says Kelly. A 2017 study found that gut bacteria, called lactobacillus, commonly found in live cultures in yogurt, can reverse depression in rats and humans, Naidoo shares in her book.

Additionally, omega-3 fatty acids are also essential for better mental health. Studies show that dietary deficiencies of omega-3 fatty acids are associated with an increased risk of developing psychiatric disorders, including depression, anxiety, bipolar disorder, schizophrenia, dementia, and autism. Fish like salmon, sardines, herring, and mackerel, are high in omega-3's, shares Kelly.

"Polyphenols found in foods like green tea and pomegranate are also key for nourishing the good gut bacteria," says Kelly. Research even shows that drinking green tea can increase healthy bifidobacteria within the gut, which has a wide range of health benefits, including better digestion and reduced risk of colon cancer. Kelly says her favorite way to get her green tea intake for the day is by drinking the Sound Green Tea with Grapefruit and Mint.

As far as foods you should have in moderation, sugar, low-fiber carbohydrates, saturated fats, and processed foods can all negatively impact your physical and mental health, as they can cause inflammation to the body, which can disrupt your gut health.

Now, all of this is not to say that medications and different therapies for mental health issues are not helpful or necessary. Food is not a cure-all for all of your mental health concerns, and medications and therapy have shown to be very helpful in managing this. However, if you want to try incorporating certain foods into your diet more regularly, then you most likely will see an increase in mood. Ultimately, though, it's all about doing what's best for you and always consult with a doctor if you're ever unsure.