How Food and Substances Affect Emotions and Brain Function

How Food and Substances Affect Emotions and Brain Function

1. The Gut-Brain Axis

• The gut is often referred to as the “second brain” because it contains millions of neurons and produces neurotransmitters (like serotonin).
  
  

• 90–95% of serotonin (the mood-regulating neurotransmitter) is made in the gut.
  
  

• The gut and brain communicate bi-directionally via the vagus nerve and chemical messengers.
  

Evidence:

• A 2020 study in Nutritional Neuroscience found that gut microbiome imbalances are associated with anxiety, depression, and heightened neuroticism.
  
  

• Probiotic and prebiotic interventions (e.g. fermented foods, fibre) have been shown to reduce emotional reactivity and improve mood.

2. Inflammatory Foods and Neuroinflammation

• Diets high in ultra-processed foods, sugars, and trans fats have been linked to chronic low-grade inflammation, which affects brain health.
  
  

• Neuroinflammation has been associated with increased symptoms of depression, anxiety, and cognitive decline.
  
  

Evidence:

• A 2015 study in Brain, Behavior, and Immunity linked systemic inflammation markers (like CRP and IL-6) with higher levels of neuroticism and mood disorders.
  
  

3. Blood Sugar and Mood Instability

• Highly refined carbohydrates and sugary foods can cause rapid blood sugar spikes and crashes, affecting mood regulation and emotional resilience.
  
  

• These crashes can mimic or trigger symptoms of anxiety, irritability, and brain fog.
  
  

Evidence:

• A 2019 study in Neuroscience & Biobehavioral Reviews showed that high glycaemic index diets were associated with increased depressive symptoms.

4. Caffeine, Alcohol, and Other Substances

• Caffeine: Can heighten alertness but may increase anxiety and neuroticism in sensitive individuals or in high doses.
  
  

• Alcohol: Acts as a depressant. While it may momentarily numb emotions, regular consumption is linked to worsened mood regulation and impulsivity.
  
  

• Nicotine, cannabis, and other psychoactives affect neurotransmitter systems in nuanced ways, sometimes offering temporary relief but often worsening baseline emotional regulation over time.
  
  

Evidence:

• A 2018 study in Frontiers in Psychology linked high caffeine sensitivity to increased anxiety in those with pre-existing high neuroticism traits.
  
  

• Another 2020 study in Journal of Affective Disorders found that frequent alcohol use correlated with greater emotional instability and neurotic traits.
  
  

5. Nutritional Deficiencies and Emotional Dysregulation

Certain deficiencies are directly linked to poor emotional and cognitive function:

🧬 Personality Traits and Diet: Is There a Link?

While emotions are state-based, neuroticism is a trait—a stable personality characteristic. But traits are not fixed. Over time, they can shift, especially when brain chemistry and lifestyle factors change.

A 2021 study in Personality and Individual Differences showed:

Individuals who improved their diet (more whole foods, less processed) showed reductions in neuroticism and increased emotional stability over time.

This supports the idea that diet affects not just moods, but personality expression over time.

Why This Matters

When we talk about holistic success and performance excellence, nutrition isn’t just about fuelling the body. It’s about fuelling the mind, stabilising emotions, and supporting the brain function that underpins everything we do. You can have the clearest strategy, the biggest goals, and the strongest will, but if your brain chemistry is working against you, you’ll always feel like you’re pushing uphill.

Born To Be Brilliant® is about creating success from the inside out. That means aligning mind, body, and soul so you can show up with clarity, energy, and resilience. The science shows that what we eat doesn’t just influence mood in the moment, it shapes long-term emotional stability, cognitive performance, and even how our personality traits are expressed over time.

Performance excellence isn’t only about what you do, it’s about the foundation from which you do it. A nourished brain and body give you the capacity to respond rather than react, to sustain energy without burnout, and to access the creativity and focus that brilliant living requires.

If you’re curious about how to integrate this kind of holistic approach into your own life and work, the Born To Be Brilliant® membership and community is where you’ll find the tools, insights, and community to help you thrive. Because when your body and brain are nourished, your brilliance has no limits.