by Caitlin Beale, MS, RDN March 11, 2021 4 min read

If you've ever felt a nervous churning in your stomach that isn't a result of your lunch, then you are familiar with the close relationship that exists between our gut and brain. As we learn more about this connection, it's apparent that the impact goes far beyond a feeling of butterflies.

This has been clearly shown in people with irritable bowel syndrome (IBS), who are much more likely to experience psychological factors including anxiety and depression. While we used to think this connection was simply based on a person's symptoms reducing their quality of life, it appears that the health of our gut may be the reason behind the mood disorders instead of the other way around. By targeting gut health, studies have shown both the successful reduction of IBS symptoms and significant improvement in moods.

An unhealthy gut can interrupt healthy hormone signals that impact mood, cognition, stress resilience and even hunger levels. Let's take a closer look at how this happens and what you can do about it.

How Does Our Gut Affect Our Health?

Your gut is home to billions of microorganisms collectively known as your gut microbiome. They perform many vital roles in the body, including the break down of indigestible fibers during digestion and supporting nutrient absorption. In addition to this, your microbiome can impact the overall health of your entire body — from immune health to metabolic health and cognitive function.

The most important factors that influence gut health are bacterial diversity and richness — or the numbers and types of bacteria present. When the balance of these microorganisms is thrown off, called dysbiosis,it can significantly impact your health.

An imbalance in gut bacteria -- dysbiosis can be caused by several factors, including:

  • Nutrition
  • Infections
  • Medication (antibiotics and NSAIDs)
  • Stress
  • Environmental toxins found in pesticides, chemicals in tap water, skin/household products and many other toxins we are exposed to that accumulate in our body

How Does Dysbiosis Influence Brain Health?

The direct connection between the gut and the brain is known as the gut-brain axis. The vagus nerve, a large sensory nerve, helps send messages from your gut to your brain and vice versa. It is via this super-highway that our microbiome can directly communicate with our nervous system.

Gut bacteria can influence hormones and neurotransmitters that affect our mood and appetite via the vagus nerve. They can even activate and send messages that influence mood on their own by producing specific bacterial metabolites. Studies have shown that people with depression have less diversity and richness in their gut. There are even interesting animal studies that have shown rats who display symptoms of anxiety become calmer after receiving fecal transplants from calm rats.

It is also known that up to 95% of feel-good neurotransmitterserotonin is made in our gut, and alterations in microbiome can directly impact its production. This key hormone impacts the entire body, it helps with digestion and eating behaviours, but is also a key mood stabilizer that affects feelings of happiness and well-being and is often used as a therapeutic target in medications for depression and anxiety.

An imbalance in the gut can lead to an increase in symptoms of anxiety, depression and brain fog. So what can you do?

Supporting the Gut-Brain Axis

Caucasion hand reaching into white bowl filled with blueberries on a wooden serving board.

Luckily what's good for your brain and gut is good for the rest of your body.

While more severe cases of dysbiosis may need a more targeted solution, here are five actionable steps you can take to support your gut-brain axis:

  1. Eat healthy fats, especially those rich in omega-3 fatty acids with EPA and DHA to support brain health, nourish the gut and balance healthy levels of inflammation. Oily fish, such as salmon or mackerel, are a great source. Aim for 5 ounces three to four times a week.
  2. Eat a nutrient-dense diet with a focus on eating the rainbow of brightly colored fruits and vegetables like berries. A powerful source of anti-oxidants, which support brain and gut health by combating free radical damage and increasing blood flow to the brain. Perfect to add to a breakfast smoothie.
  3. Consider probiotics either from food that contain live micro-organisms (fermented foods are a great source) or appropriate supplementation to boost bacterial diversity and repopulate the gut. It is important to note that any bacterial overgrowth would need to be addressed first before introducing probiotics.
  4. Manage stress levels, as high cortisol is linked both to an unhealthy gut and increased levels of brain inflammation. Calming activities including yoga, breath work and meditation have been shown to help reduce stress levels.
  5. Get adequate rest, as sleep promotes optimal repair and regeneration overnight. Altered circadian rhythms can also negatively impact our gut microbiome and consistently getting 7-9 hours of sleep will have widespread benefits on overall health.

Our overall health relies on the intricate connection of every system in our body. If one system is out of balance, it has a domino affect that can lead to one issue after another. Understanding the gut and brain connection, while nourishing your microbiome through diet and lifestyle factors will promote looking and feeling your best - mind and body.



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