How does the gut-brain connection impact cognitive health?

Your gut is more than just your digestive system. When you really dive into the details, your gut is home to tens of trillions of microorganisms, which make up your gut microbiome. We collect most of these gut microbes when we’re born as we pass through the birth canal, but other factors like a Cesarean delivery or antibiotic use can also impact our microbiome.

While bacteria often get a bad rep, the bacteria that make up our microbiome are essential for keeping our body and brain healthy and happy.

Studies show that the bacteria in our guts can impact our mood, leading us to feel more happy, relaxed, anxious, and sad.1 They can also influence our focus, helping us maintain mental clarity and cognitive sharpness.

Beyond our emotional states, research suggests an imbalanced gut could impair cognitive function, making it harder to learn, recall information, and stay focused. Recent studies have even found that microbiome imbalances may be linked with Alzheimer’s disease.2

So if you’ve ever wondered whether your gut and what you eat could impact your brain health — signs (and science) point to yes.

How does the gut and brain connection work?

Tucked within the walls of our digestive tract lies a critical player: the enteric nervous system (ENS). It’s because of the ENS that researchers have now started calling the gut our body’s “second brain.”

This “second brain” is made up of 100 million nerve cells organized into two thin layers that line your gastrointestinal tract from top to bottom.1

While the gut isn’t conscious in the same way we think of the brain as being, it does communicate with the brain using microbes and bacteria that send signals between the gastrointestinal tract and the central nervous system along a pathway called the gut-brain axis. Researchers believe it’s this bidirectional axis that may allow the gut to trigger shifts in mood, and for our emotions to affect our gut.1

Aside from communicating with the brain, the ENS is responsible for numerous essential functions1:

• Controls every aspect of digestion
• Swallowing
• Releasing enzymes that break down foods
• Blood flow that supports nutrient absorption
• Blood flow for elimination of waste

Put another way, the enteric nervous system is responsible for metabolizing food and converting it to vital nutrients that can then be used to support brain health, focus, and mental clarity.

Consider when you eat spinach. 

Spinach is packed with essential vitamins like folic acid, vitamin K, vitamin C, vitamin A, iron, and more. But your brain can’t benefit from those vitamins until the ENS has broken the spinach down.

When your gut microbiome is imbalanced, it becomes harder for your gut to break down nutrients. Oftentimes, this can leave your brain and body without the levels of essential vitamins they need to function properly. When the brain doesn’t receive enough vitamins, it can affect neurotransmitter synthesis, which can contribute to brain fog.

(Brain fog is characterized by a lack of mental clarity, difficulty focusing, confusion, and forgetfulness.)

 

Gut health and cognitive health

Research into Alzheimer’s suggests that gut health and memory may be more linked than previously thought.

For instance, new research presented at the Alzheimer’s Research UK Conference 2022 found links between gut bacteria and inflammation, memory issues, and Alzheimer’s.2

One of the studies discussed analyzed the blood samples of 68 individuals with Alzheimer’s and 68 people without it. In analyzing the blood, researchers found a distinct gut bacteria profile for those with Alzheimer’s, alongside higher levels of inflammation markers in their blood and stool samples. When the researchers treated brain stem cells with the blood from Alzheimer’s patients, those cells were less able to grow new nerve cells.2

Another study presented at the Conference shared the impact of transplanting stool samples from people with and without Alzheimer’s into rats. The results? Rats who’d received stool samples from people with Alzheimer’s had higher levels of inflammation in the brain, performed worse on memory tests, and failed to grow as many new nerve cells in memory regions of the brain as rats who received healthy stool samples.2

Professor Yvonne Nolan, who led the study alongside partners in London and Italy, shared that “Our findings suggest that symptoms of Alzheimer’s may, in part, be caused by abnormalities in the gastrointestinal tract.”2

In this way, our gut microbiome seems to be able to influence the levels of inflammation in our blood as well as affect memory regions in the brain, which can impact our ability to learn, recall information, maintain focus, and achieve mental clarity.

The connection between gut health and mental health

Our gut microbiome also seems to play a role in how we feel and our mental health.

One study conducted by Dr. John Cryan, a neuropharmacologist and microbiome expert, found that mice who ate a specific probiotic bacteria demonstrated more relaxed behavior than those who didn’t. This probiotic, Lactobacillus rhamnosus, carries GABA, a neurotransmitter that helps manage brain activity and is thought to play a big role in calming anxiety, stress, and fear.3

His findings suggest that what we eat and our microbiome can directly influence the neurochemicals that help moderate our emotional states and mental health.3

Another study found that our gut microbes help moderate our levels of serotonin, a neurotransmitter that’s largely responsible for clear thinking, mood, happiness, and more.4 

How to take care of your gut

If you want to improve your mental performance, enhance focus, and preserve your brain health for the long haul, getting a grip on your gut health is a great place to start. Here are a few tips to help: 

• Add probiotics to your diet

Studies have shown probiotics to effectively reduce depression and anxiety symptoms at levels near common prescription medications.5 These effects likely come through supporting healthy levels of neurotransmitters like GABA and serotonin which can play important roles in maintaining mental health.

Some great probiotic options to consider include:

• Kefir
• Yogurt
• Sauerkraut
• Kombucha
• Kimchi
• Sourdough bread
• Pickles
• Miso

Of course, talk with your doctor before making any shifts to your current treatment plan.

• Create your own relaxation routine

Stress can have a big effect on the delicate balance of bacteria in your gut.6 Learning to manage stress is an essential part of preserving your microbiome and enhancing mental clarity. Prioritizing time to let go and relax are great ways to downregulate your stress response.

If you find it hard to relax, try creating your very own relaxation routine.

Here are a few activities to help you get started:

• Go for a walk in nature
• Exercise
• Journal
• Focus on your breath
• Meditate
• Create art (watercolor, sculptures, DIY projects)
• Visit a sound bath
• Aromatherapy
• Connect with a loved one

The Muse S Headband and the Muse 2 Headband are innovative EEG headsets designed to help you harness the calming power of meditation to live a more relaxed and present life. 78% of users felt more relaxed when using our device. Learn more here > 

• Consider talking with a specialist

We all have distinct strains and levels of certain bacteria that make the needs of our gut microbiomes special to each of us. 

So if you’re struggling and feel the problem may lie in your gut, it could be best to talk with a specialist (a gastroenterologist) to uncover your gut’s unique needs and how you can balance your microbiome for greater overall health, focus, and mental clarity.

By nurturing your gut health and incorporating these practices, you can pave the way for enhanced cognitive function, better mental health, improved focus, and overall well-being.

Tune into this Untangle episode on the mind-gut connection and mood with Dr. Emeran Mayer: