This week’s guest blog is from Gillian Crooks


The Gut-Brain Connection: How To Feed Your Brain


If there was ever a call for digestive health, this is it!

There is no denying it anymore- gut health is important for overall health. According to recent research, your gut has an intimate relationship with brain health and function. The gut has been called the “second brain” in recent years because of this relationship.

New discoveries about the interconnectedness of the Enteric Nervous System (ENS), the vagus nerve, digestive microbes, and the gut-brain connection have proven that what you consume affects your brain. These discoveries have had many implications for our understanding of how the brain interacts with the body and vice versa. For example, we used to think that our mental state (brain) was a predictor for Irritable Bowel Syndrome (gut), but researchers have discovered that this relationship can be inverse as well; the foods you consume (gut) can have an impact on your mental state (brain). The food we eat is interconnected with our experience of things like depression and anxiety.

Amazing. It’s not too surprising when you slow down to think about it though- why wouldn’t the foods we eat matter, right? Why would we ever think that there wasn’t a correlation there. Eating is our body’s way of keeping our systems going, naturally the foods we eat would influence things!


What Exactly is the Gut-Brain Connection?

It’s a complex system, and we’re still learning a lot about it. There are multiple things working together, like:

  • The vagus nerve that links the gut directly to the brain
  • The Enteric Nervous System (“the second brain”) that helps with the intricacies of digestion
  • The massive amount of neurotransmitters produced by the gut
  • The immune system’s relationship with the gut-brain connection and its functioning for overall homeostasis
  • The interactions and neural messages sent by the gut microbes

The above inter-relationships are unquestionably complex. Let’s briefly consider each aspect.


Vagus Nerve

The Vagus Nerve (Cranial Nerve X) runs from the brain stem to the gut, reaching as far as the colon. Research has indicated that up to 90% of the neural activity of the vagus nerve is afferent, meaning that the neural signals run from the gut to the brain and not the other way around (Berthoud and Neuhuber, 2000). The vagus nerve relays a variety of information to/from the brain, such as heart rate, gut state (i.e., peristalsis), sweating, and much more. 

The Enteric Nervous System and Neurotransmitters

Did you know that the gut has more neurones than the spinal cord?

It’s an amazing fact, considering the spinal cord has approximately 69 million neurones. That’s why the ENS is colloquially referred to as the “second brain”. The ENS has between 200-600 million neurones (Furness et al., 2014). These neurones “speak” to each other by way of chemical messengers called neurotransmitters. Many of these neurotransmitters have a strong effect on mood and brain health, such as serotonin. Serotonin is a key hormone that stabilizes mood and feelings of well-being and is commonly thought to originate in the brain, however; research has shown that up to 95% of serotonin is made in the gut, and not the brain (Carpenter, 2012).


The Immune System of the Gut

Eating and drinking is a huge portal where disease-causing critters can get into your body. It makes total sense that much of our defence system would be located in the gut too, right?

Up to 75% of our immune system exists in our gut. Immune cells can move throughout the body and cause inflammation just about anywhere, which is why anti-inflammatory diets have been very popular. If immune cells are “activated” by something in the gut, they can potentially wreak havoc anywhere in the body, including the potential to cause inflammatory responses in the brain. Many auto-immune conditions are now being researched for links to gut health.


Gut Microbes

Your friendly neighbourhood gut residents. You have billions happily living in your gut right now, and they do amazing things like help you digest certain foods, make certain vitamins, and even help regulate inflammation. More research is needed to show the impact of your gut microbiota, but evidence is already pointing to a link between your gut microbiome and its the impact on mood and brain health.


How Do These Things All Work Together for Brain Health?

The honest answer to how these things all work together is that we really don’t know just yet, but research is ongoing and very promising. One thing is clear: a healthy gut goes hand-in-hand with a healthy brain. So how do we feed our brain what it really needs?

Of course, a variety of minimally-processed, nutrient-dense foods is required, because no nutrients work alone. Two things you may want to consider eating more of are fibre-dense foods and Omega-3 Fats. Fibre (in fruits, vegetables, nuts and seeds) help to feed your gut microbes, and Omega-3 Fats (in fatty fish, walnuts, algae, flax, chia, and hemp) are well-known inflammation-busting brain boosters.

Research is beginning to demonstrate that the gut-brain connection has clear and far-reaching implications for treatment alternatives to prescription medications. Generally speaking, improving lifestyle and nutrition is something that people don’t regret and empowering oneself to make these changes has many positive benefits to overall health and quality of life.


Blueberry Hemp Overnight Oats

Full of fibre for the gut and Omega-3 fats for the brain! Enjoy!

Serves 2


1 cup blueberries (fresh or frozen)

1 cup oats (gluten-free)

1 cup almond milk

1 tablespoon chia seeds

2 tablespoons hemp seeds

½ teaspoon cinnamon

1 banana, sliced

¼ cup chopped walnuts


  1. Blend blueberries in the food processor until smooth.
  2. Mix blueberries, oats, almond milk, chia seeds, hemp seeds in a bowl with a lid. Let set in fridge overnight.
  3. Split into two bowls and top with cinnamon, banana, and walnuts.

Tip: Your gut microbes love to eat the fibre in the blueberries, oats, seeds, and nuts. Meanwhile, your brain loves the omega-3 fats in the seeds and nuts. 


  1. Berthoud HR, Neuhuber WL. Functional and chemical anatomy of the afferent vagal system. Autonomic Neuroscience. 2000, Dec 85 (1-3):1-17.
  2. Furness JB, Callaghan BP, Rivera LR, Cho HJ. (2013). The enteric nervous system and gastrointestinal innervation: integrated local and central control. Adv Exp Med Biol. 2014 817:39-71.





About the Author

Gillian grew up in the East Coast of Canada. At the age of 19, she was diagnosed with Multiple Sclerosis. She was in and out of hospitals and a pin cushion for medications before discovering the power of a natural, whole-foods diet, coupled with a healthy lifestyle. The results have been amazing- she went from using a wheelchair and cane and vision loss to crossing finish lines of numerous half and full marathons and triathlons. Gillian’s next challenge is a half Ironman.

Gillian is living proof that dedicating oneself to a natural, healthy, and sustainable lifestyle has powerful benefits. She works as a Registered Holistic Nutritionist at Rehab1 Performance Center in Moncton, NB. Gillian loves to help others embrace lifestyle changes through movement and nutrition.

You can find out more about Gillian at

Photo credit: Johnny Gonzales