HOW the regular consumption of OLIVE OIL POLYPHENOLS can SUPPORT your mental health

1. A growing mental health crisis

Depression and anxiety are among the most prevalent health conditions in the modern world. The World Health Organization (WHO) estimates that over 280 million people globally suffer from depression, making it a leading cause of disability worldwide. Despite the widespread availability of pharmaceutical treatments, a large proportion of patients either do not respond adequately to medication or experience significant side effects. This has prompted growing scientific interest in dietary factors that may support mental health.

What most people do not realize is that mood, sleep, and psychological resilience are not simply matters of willpower or circumstance. They are deeply rooted in biochemistry. The brain relies on a delicate network of chemical messengers called neurotransmitters, most notably serotonin and dopamine, to regulate how we feel, think, and sleep. When this network is disrupted by poor diet, chronic stress, and/or chronic inflammation the consequences manifest as low mood, anxiety, disturbed sleep, and diminished motivation.

Emerging research now points to the polyphenols in extra virgin olive oil, the cornerstone fat of the Mediterranean diet, as a meaningful dietary ally in preserving and restoring this neurochemical balance. This blog explores the mechanisms through which olive oil polyphenols support the brain and why populations consuming the most olive oil consistently show lower rates of depression and anxiety.

2. The serotonin system

Serotonin is often called the "feel-good" neurotransmitter. It plays a central role in regulating mood and emotional stability, and sleep. The brain produces serotonin from a building block called tryptophan, an essential amino acid obtained through food. Under healthy conditions, tryptophan is converted into serotonin through a well-regulated enzymatic process, which we call here pathway I.

However, tryptophan does not travel exclusively down the serotonin pathway (pathway I). An alternative biochemical route, known as the kynurenine pathway (pathway II), competes for tryptophan. When activated, pathway II diverts tryptophan away from serotonin production and produces a cascade of inflammatory neurotoxins linked to neuroinflammation, depression, and impaired cognitive function.

The critical factor determining which pathway, I or II, dominates is inflammation. Chronic low-grade inflammation, driven by modern diets high in processed foods and refined sugars, heavily activates the kynurenine pathway (pathway II). The result is much less serotonin synthesis, leaving many people predisposed to low mood, anxiety, and disrupted sleep.

3. The Mediterranean diet: a natural buffer against depression?

Epidemiological studies have long noted that populations following a traditional Mediterranean diet show consistently lower rates of depression and anxiety compared to those consuming a Western dietary pattern. While this association has multiple contributing factors, the regular consumption of extra virgin olive oil, rich in bioactive polyphenolic compounds, is increasingly recognized as one of the key drivers of this protective effect.

The Mediterranean diet derives 60-70% of its fat from extra virgin olive oil. Its other core components include vegetables in generous amounts, legumes, whole grains, nuts, fatty fish (e.g., sardines), and moderate amounts of dairy and poultry. Extra virgin olive oil is the unifying element, present in virtually every meal, and its polyphenols exert a broad range of biological effects that extend well beyond basic nutrition.

But what exactly do these polyphenols do inside the brain and body? Below, we explore 3 key mechanisms through which olive oil polyphenols support the serotonin system and overall mental wellbeing.

• 4.1 Olive oil polyphenols protect the serotonin pathway by reducing inflammation. The most fundamental way olive oil supports mental health is by addressing the root cause of serotonin depletion: chronic inflammation. The polyphenols in extra virgin olive oil are potent anti-inflammatory agents. They achieve this primarily by suppressing the NF-kB signaling pathway, one of the body's master regulators of the inflammatory response. By dampening chronic inflammation, olive oil polyphenols reduce the activation of indoleamine 2,3-dioxygenase (IDO), the enzyme responsible for diverting tryptophan away from serotonin production and toward the kynurenine pathway (pathway II). In practical terms, this means that when inflammation is reduced through a polyphenol-rich diet, more tryptophan remains available for serotonin production. The result is greater emotional stability and enhanced psychological resilience.

• 4.2 Olive oil polyphenols preserve serotonin and dopamine by inhibiting their breakdown. Even once serotonin is successfully produced, it faces a second threat: enzymatic degradation. Two enzymes, monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B), continuously break down serotonine in the synaptic cleft, the tiny gap between nerve cells where chemical communication takes place. When these enzymes are overactive, serotonin is cleared too quickly, reducing their availability and shortening their signalling duration. Research published in Nutrients (2025) demonstrated that polyphenols function as natural inhibitors of both MAO-A and MAO-B (Nutrients, 2025). By inhibiting these degradation enzymes, olive polyphenols extend the active lifespan of serotonin in the brain, amplifying their mood-stabilizing and motivational effects. Hydroxytyrosol, one of the most abundant polyphenols in extra virgin olive oil, is particularly noteworthy in this context. Structurally related to dopamine, it has been shown to protect dopamine from oxidative self-destruction. A study by Goldstein et al. (2016) found that hydroxytyrosol decreased the toxic dopamine metabolite DOPAL by 30% and reduced oxidative damage markers by 49%. This neuroprotective action directly supports the brain's reward and motivation circuitry, the neurological foundation of drive, pleasure, and engagement with life.

• 4.3 Olive oil polyphenols boost serotonin production through the gut-brain axis. Perhaps the most surprising finding in recent neuroscience is that approximately 95% of the body's serotonin is not produced in the brain but in the gut. Specialized cells lining the gastrointestinal tract, known as enterochromaffin cells, produce and release serotonin in response to signals from the gut microbiome and its metabolic by-products. The composition of the gut microbiome is therefore a mental health concern. A microbiome dominated by beneficial bacteria produces short-chain fatty acids, which stimulate enterochromaffin cells to increase serotonin output. A microbiome disrupted by a poor diet does the opposite, suppressing gut serotonin production. Olive oil polyphenols have a strong prebiotic effect, selectively promoting the growth of beneficial bacterial strains such as Bifidobacteria and Lactobacillus while suppressing bad ones. This optimization of the gut microbial environment enhances the production of short-chain fatty acids, which in turn stimulates serotonin production in the gut.

5. Conclusion

Mental health is inseparable from physical health, and the brain's neurochemical environment is shaped by diet. The evidence reviewed here points to a consistent picture: the polyphenols in high-quality extra virgin olive oil support serotonin balance through at least 3 complementary mechanisms that help explain why populations adhering to the Mediterranean dietary pattern consistently demonstrate lower rates of depression and anxiety in large-scale epidemiological studies. While olive oil is not a substitute for professional mental health treatment, the existing body of scientific evidence makes a compelling case for its role as a meaningful dietary contributor to psychological resilience and neurotransmitter balance. This makes choosing a polyphenol-rich extra virgin olive oil as your primary source of dietary fat is one of the most evidence-based, simple steps to support both your mood and mental health.

References:

D'Errico et al. (2025). Polyphenol-Enriched Extracts from Leaves of Mediterranean Plants as Natural Inhibitors of Monoamine Oxidase (MAO)-A and MAO-B Enzymes. Nutrients, 18(1), 22.

Goldstein, D.S., Jinsmaa, Y., Sullivan, P., Holmes, C., Kopin, I.J., & Sharabi, Y. (2016). 3,4-Dihydroxyphenylethanol (Hydroxytyrosol) Mitigates the Increase in Spontaneous Oxidation of Dopamine during Monoamine Oxidase Inhibition in PC12 Cells. Neurochemical Research, 41(9), 2173–2178.

Chiang, Y.F., Hung, H.C., Chen, H.Y., et al. (2020). The Inhibitory Effect of Extra Virgin Olive Oil and Its Active Compound Oleocanthal on Prostaglandin-Induced Uterine Hypercontraction and Pain. Nutrients, 12(10), 3012.

Szmidt, M.K., Granda, D., Madej, D., Sicinska, E., & Kaluza, J. (2023). Adherence to the Mediterranean Diet in Women and Reproductive Health across the Lifespan. Nutrients, 15(9), 2131.

Summerhill, V., et al. (2018). Vasculoprotective Role of Olive Oil Compounds via Modulation of Oxidative Stress and Nitric Oxide. Frontiers in Cardiovascular Medicine.