Nutrition’s Effect on Mood, Cognition & Behavior: What’s the Connection?

Photo by Caju Gomes on Unsplash

In this post, we’ll explore the relationship between nutrition and mental health, with references to the latest research. But first, I’d like to share the very personal experience that opened my eyes to this connection.

Ten years ago, my son was diagnosed with Asperger’s Syndrome. After processing and absorbing that news for a few days, I did what I always do when faced with something big – I dug into the research, and immersed myself in any and all information I could find on Asperger’s and autism spectrum disorder (ASD). As I educated myself about his new diagnosis and researched ASD therapies, I learned about biomedical treatments, and specifically nutrition-based interventions.  Many parents in the online autism forums I joined shared the amazing progress their children were making as a result of dietary modifications and nutritional supplements, and I was intrigued.  How could nutritional support make such a profound difference for kids with a neurodevelopmental disorder?

In the decade since then, my son has benefitted greatly from nutritional therapies. As a result of my family’s experience, I’ve become a staunch advocate for holistic, nutrition-based alternatives to conventional treatment approaches. Ultimately, I decided to return to grad school for a Master’s degree in Holistic Nutrition, so I could offer nutritional consulting to families of kids like mine as well as help people with a wide range of health conditions support their body’s innate healing capabilities with evidence-based nutrition.

Research now confirms that what we eat affects so much more than just our physical health. A large and growing number of studies show that there is a significant connection between nutrition and mental and emotional wellbeing as well. 

What exactly is this connection between nutrition and mental health?  How does what we eat affect our mood, cognition, and (as a result) our behavior?  While game-changing nutritional interventions can often be relatively simple, the science behind why these interventions work is more complex and more research is needed to fully understand the mechanisms at play. However, there’s quite a bit that we do know about how nutrition affects mental health.

The relationship between nutrition and mental health is mediated in large part by what happens in the gut, and specifically along the gut-brain axis.  The gut-brain axis is a bidirectional signaling pathway between the central and the enteric nervous system, which links the emotional and cognitive centers of the brain with gastrointestinal functions. It also intersects with branches of the endocrine and immune systems.  Gut microbes create signaling molecules that send messages to the brain along the gut-brain axis, influencing our mental and emotional states, and signals also transmit in the opposite direction allowing cognition and mood to affect gut function.  

Gut microbes produce many compounds critical to brain function. These include neurotransmitters such as serotonin, norepinephrine, dopamine, and GABA as well as short-chain fatty acids and vitamins that play an important role in modulating cognition, mood, and behavior. In fact, 90–95% of serotonin is produced in the gastrointestinal tract! 

These compounds, or microbial metabolites, interact with the brain along various pathways. The pathways include endocrine, neuroendocrine, immune, and neurotransmitter signaling routes.  Microbial metabolites activate fibers of the vagus nerve (which transmits signals between the digestive system and organs to the brain), they stimulate the immune system within the gut (activating immune signaling molecules into the bloodstream which ultimately reach the blood brain barrier), and they are also directly absorbed into the bloodstream from where they can interact with other organs, including the brain.

Inflammation plays a critical role in this relationship as well. Research shows that physiological pathways involving inflammatory and stress responses play an important role in mental health. One plausible evidence-based explanation for how inflammation influences mood and mental health is the finding that psychological stress can increase intestinal permeability and allow bacterial endotoxins to enter the bloodstream, causing peripheral inflammation which can then spread to the central nervous system (CNS) causing a neurotoxic reaction. 

So how does this translate into actionable nutritional guidance?  How do our day-to-day dietary choices influence our mood, cognitive functioning, and behavior?  

Dietary patterns matter. A Western dietary pattern, a.k.a the “Standard American Diet” with its heavily processed foods high in sugar and saturated fat, is strongly associated with adverse impacts to mental health. This type of diet leads to increased inflammation, intestinal permeability and nutrient deficiencies, all of which are linked to adverse impacts on brain functioning and overall health. Conversely, a diet rich in fruits and vegetables, high in healthy fats, nuts, and fatty fish, and low in processed food (i.e., an anti-inflammatory Mediterranean-style diet) is associated with the greatest mental health benefits. Limiting processed foods and increasing intake of nutrient-dense whole foods can make a big difference in mental health, and of course, it’s optimal for physical health as well. 

Brains need specific nutrients for optimal functioning. Mood and cognition depend on the brain functioning at its best, and there are a number of vitamins, minerals, and other nutrients that the brain needs to support neurotransmitter synthesis, neurotransmission, and other critical brain functions. If adequate nutrients can’t be obtained from the diet (or in the case of metabolic/absorption issues), supplementation of certain nutrients may be beneficial. 

Gut health is crucial. Eating a clean, well-balanced whole foods diet goes a long way in establishing and maintaining a healthy gut, but additional steps may be needed. Gut dysbiosis, intestinal permeability (i.e., “leaky gut”), food sensitivities and other gut health issues can all persist and cause problems even on the healthiest diet.  Identifying and addressing gut health issues is critically important.

Nutrition doesn’t just affect mood, cognition, and behavior – it is essential for optimal mental health. The good news is that even relatively simple changes to improve diet, nutrition, and gut health can make a profound difference. 

Are you interested in optimizing your health and wellness through individualized nutritional support?  I offer nutrition consults via phone and video conferencing tailored to your specific goals and needs.  Visit my Work With Me page to learn more.  I look forward to connecting with you! 

3 thoughts on “Nutrition’s Effect on Mood, Cognition & Behavior: What’s the Connection?

    1. Hi Maria – thanks for reading and commenting! I’ll get in touch with you via text or Facebook to discuss potential next steps. You can learn more about the support I provide on my Work With Me page ( but since you’re family, you don’t have to go through the usual channels. 😉

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