Research Highlight: You Feel What You Eat

Research Highlight: You Feel What You Eat

Apr 18, 2019

Research Highlight: You Feel What You Eat

Have you ever had a “gut feeling” about something? Do you feel sick to your stomach when you feel anxious? Do you ever notice the effects of eating fast food on your mood? What about when you eat a healthy meal - do you feel different?

The anatomy

To understand a bit more about the digestive process, there is a bit of anatomy that you need to understand. The central nervous system (CNS) is made up of the brain and spinal cord and controls all of your body’s actions and responses, like pulling your hand out of too-hot water. The autonomic nervous system (ANS) governs automatic processes like your heartbeat and digestion. The enteric nervous system (ENS) is a part of the ANS but specifically governs the function of the gastro-intestinal (GI) tract, which is made up of the mouth, esophagus, stomach, and intestines. The role of the ENS is to sense changes in the gut, regulate digestive enzymes and neurotransmitters, and control the movement of food through the digestive system.

The ENS is often referred to as the “second brain” because it can operate without direction from the central and autonomic nervous systems. The ENS largely dictates the makeup of bacteria that resides within our gut, which is called the microbiome. The microbiome contains tens of trillions of bacteria, and the quality and variety of food we eat is essential to the balance of microorganisms in the microbiome.

The bacteria in the microbiome

“Good” bacteria in the microbiome produce neurotransmitters and hormones that regulate emotion and mood. Disruptions to this good bacteria, like when you’re sick or on antibiotics, can therefore disrupt your mood. Conditions like anxiety and depression can also affect the bacteria in the microbiome.

What’s more, the food you eat also has an effect on your microbiome. Eating food that is unhealthy, over-processed, or that you can’t digest can cause inflammation and an overgrowth of bad bacteria in your gut.

In mice, probiotics (which boost good bacteria) have been shown to decrease anxiety, demonstrating a connection between gut bacteria and mental health. And although the majority of testing of this gut-brain connection has not been done with humans, and there is no proof that improving gut bacteria is a cure-all, there is a lot of exciting research happening that is exposing more of the connections between the brain and gut.

What comes first, the chicken or the egg?

So is your gut affecting your mood or is your mood affecting your gut? It seems to go both ways. Feeling down can affect your gut bacteria, making you feel worse and more likely to reach for unhealthy comfort foods (salt, sugar, and fat), starting a downwards spiral of physical and emotional effects. Feeling physically sick or “off” can affect your mood, starting the same trend. So what can you do about it?

Start by being easy on yourself. Improving your gut health, like improving mental health, is a journey. It starts with having healthy snacks available when you’re feeling hungry or feeling down, so that your available food doesn’t contribute more to your off mood.

What’s the bottom line?

The basic message of studies like this is that there is a possibility that improving the functioning of your gut can help with other mental health symptoms. A doctor or naturopath can make specific recommendations to you if you are interested in improving your gut health; some of the basic recommendations usually include reducing your consumption of processed food, sugar, gluten, and dairy.

If you are having digestive issues, you can also try an elimination diet, where you take away all of the potential diet triggers to gut problems for a few weeks and then re-introduce them one by one to see what makes you feel bad. We recommend only making changes to your lifestyle under the care of your doctor, and never change your approach to medication without consulting your health-care team.


The microbiome-gut-brain axis: from bowel to behavior.
J. F. Cryan, S. M. O’Mahony. First published: 08 February 2011. Accessed 29 September 2018.

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