A Gut Reaction: How what we eat affects our mental health

In this guest post, Functional Nutritionist Elisa Haggarty explains the vital link between digestive health and brain well-being, the importance of prebiotics, and how too much sugar can leave you sad and stressed.

You’ve heard the saying, “I just had a gut feeling”? Well, it turns out the link between mental health and the digestive system isn’t just some imagined hocus pocus, rather, there is a growing body of legitimate science showing that the bacterial ecosystem in the gut directly influences how we think and feel. 

Physical connections

For hundreds of years, Western medicine viewed mental health as completely separate from the digestive and immune systems; the human body was seen as compartmentalized and diseases were regulated to specific regions of the body without much thought as to how all the systems work in synergy.But now this approach has been turned on its head. These days, almost every MD (who is keeping up with the latest science) has books on their shelves like The Second Brain by Michael Gershon or Martin J Blaser’s Missing Microbes, while articles on nourishing the gut are popping up in our social media feeds faster than you can say ‘holistic’. 

Healthy gut, healthy brain

But what exactly do the gut and the enteric nervous system (which governs gastrointestinal function) have to do with the health and performance of the brain?In a nutshell, the central nervous system is connected to the enteric nervous system through the vagus nerve. The biggest nerve in the human body, the vagus runs from the base of your spine up your brainstem and is responsible for a range of crucial functions, including enzyme activation, insulin modulation, stomach acid regulation and releasing neurotransmitters that tell your lungs to breathe and your heart to beat.We can no longer compartmentalize mental health to the brain when everything we eat and consume impacts the enteric nervous system, and thus, the brain.  It's been proven that over 70% of the serotonin (aka the ‘happy’ neurotransmitter) found in the brain comes directly from the gut. Benzodiazepine is an over-prescribed anti-anxiety medication used in helping to manage stress, but it is now clear that a strong digestive system has the receptors and ability to produce its own Benzodiazepine.Essentially, science is showing that we each already have our own built-in anti-anxiety system governed by the gut. 

Diet as anti-depressant

Maintaining good gut health, and therefore ensuring optimum brain performance and mental well-being, is a lot about what you eat. Everything from brain fog and ADHD to depression, anxiety and even Alzheimer’s can be combated through a diet that gives the good microbes in the gut a chance to thrive. So what should – or rather shouldn’t – you be eating? Most of us instinctively know that too much sugar is bad for the brain; personally, if I eat something super sweet I’m left feeling scattered, depressed and anxious all at once.This is because sugar directly damages the gut and microbe production, and stripes the body of magnesium and B vitamins.However, it's not enough to just limit our sugar intake; we must nourish the gut with prebiotics, which help provide the fuel for our good bacteria to colonize and proliferate.So, is the occasional Yakult the answer? Unfortunately no. While some unsweetened yogurts can be beneficial, most cause more harm than good. If you want a healthy brain, skip the strawberry Yoplait and ‘probiotic chocolate’ and instead focus on prebiotic rich foods like leeks, asparagus, garlic, onions, artichokes and dandelion greens.These foods aren't sexy (and they don't own a share in the trillion dollar food industry), but they are the real superfoods, laying the foundation for a resilient gut which ultimately helps create a healthy, happy brain.  If you need some epicurean inspiration, scroll down to find my recipe for Almond Encrusted Chicken Tenders – best enjoyed over a bed of fiber and prebiotic packed greens, with an antioxidant-rich pomegranate seed and olive oil dressing. It’s a gut-friendly meal that’s really a no-brainer for mental health. Elisa Haggarty is a Functional Nutritionist and the founder of nutrition consulting program Culinary Farmacy. She is leading The Brain Fog Solution, a 30-day online course starting 5th February which focuses on improving brain function and mental resilience through diet and lifestyle changes. Chōsen members can get $100 off the cost of the course using the code ‘tribe’. 

Almond Encrusted Chicken Tenders

(they’re kid approved too!)

  • 1 lbs of pastured/organic chicken
  • 2 pastured eggs, whisked together
  • 1 cup of almond flour
  • 1 tsp dried oregano
  • 1 tsp dried basil
  • 1 tsp sea salt
  • 1/2 tsp garlic powder
  • 1 dash of cayenne pepper


  1. Pre-heat oven to 400 degrees.
  2. Slice the chicken into thin strips.
  3. Coat the chicken in the egg batter
  4. Combine the almond flour, herbs and spices in a bowl, then drop in the chicken strips (4-5 at a time) and coat them well.
  5. Place the chicken strips on a baking tray and cook for 12 minutes, then flip over and cook for another 10-12 minutes or until lightly brown on the outside.


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