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What we eat shapes our mood, brain health, and mental health.

Mediterranean-style eating provides remission rates equal to antidepressant medications.

Gut microbes and psychobiotics influence brain chemistry, including serotonin and GABA.

Most medical schools do not provide adequate nutrition training, and patients suffer as a result.

Psychiatrists are trained to prescribe medicines, refer patients to psychotherapists, and perform procedures — such as ECT, TMS, or IV ketamine. But this is changing. Some psychiatrists are learning to utilize an equally valuable and effective strategy for relieving suffering and promoting mental health.

The idea that diet and nutrition have significant effects on mood and mental wellbeing would have been dismissed as fringe medicine two decades ago. But research increasingly demonstrates that healthy nutrition improves mental health, and an entirely new subspecialty has formed to support this.

Nutritional Psychiatry

Nutritional psychiatry — which is the study of how dietary patterns, nutrients, and gut-brain interactions influence our mental health — is expanding rapidly. Research in nutritional psychiatry grew 15-fold from 2000 to 2024, which reflects the growing interest in this topic. Over 31,000 articles were published during this period. This is also evidence of the increasing acceptance of the role diet plays in our mental health.

Epidemiological evidence, particularly for depression, suggests there’s an association between the quality of our diet and our mental health. These associations don’t appear to be explained by other demographic or lifestyle factors.

Perhaps the most important single study in this field is the 2017 SMILES trial. It was the first randomized controlled trial designed to evaluate a dietary intervention for reducing depression in adults with clinical depression.

The SMILES trial was a 12-week, single-blind, randomized controlled trial of a dietary intervention as a treatment for moderate to severe depression, with depressive symptoms used as the primary endpoint. These symptoms were assessed using the Montgomery–Åsberg Depression Rating Scale.

The results were amazing. Remission was achieved for 32.3% of the intervention group and only 8.0% of the control group.To put this in perspective, the STAR*D trial, which was the largest and most influential antidepressant trial ever conducted, enrolled over 4,000 patients with major depression and found about one-third of participants reached remission after 12–14 weeks of treatment with the antidepressant citalopram.

That means the SMILES dietary intervention achieved a remission rate equivalent to the antidepressant tested in the STAR*D trial. And it did this without medication, without side effects, and without the diminishing returns patients experienced as they moved through the STAR*D trial's subsequent treatment levels.

The Mediterranean Diet leads the evidence

A Mediterranean-style diet, rich in fruits, vegetables, olive oil, fish, and legumes, has shown the strongest evidence for mental health benefits. Multiple randomized controlled trials have demonstrated that this style of eating reduces the risk of depression and anxiety. Its benefits are likely the result of anti-inflammatory, antioxidant, and vascular mechanisms, all of which directly affect how our brain functions.

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The HELFIMED trial replicated and extended these findings. A Mediterranean-style diet supplemented with fish oil produced greater improvement in depression and improved quality-of-life at three months, with improvements persisting for six months. Individuals who adhered to the Mediterranean-style diet experienced reduced depression, particularly when they ate more nuts and more diverse vegetables.

In order to understand how food affects our mental health, we need to take a look at neurobiology. The food we eat influences numerous systems in our body including inflammation, oxidative stress, the gut microbiome, epigenetic modifications, and neuroplasticity.

The gut microbiome is especially important. Psychobiotics are probiotic organisms that exhibit positive effects in individuals who are treated for mental disorders. These organisms can produce neurotransmitters such as gamma-aminobutyric acid (GABA) and serotonin, as well as short-chain organic acids (SCOAs) which affect the nervous system. Approximately 90% of the body's serotonin is produced in the gut. So, what happens in our gut has a profound influence on what goes on in our brain.

Specific nutrients with psychiatric evidence

Beyond specific diets, certain individual nutrients can also influence our mental health. Selective food supplements can be beneficial in the treatment of psychiatric disorders, including S-adenosylmethionine (SAM-e), N-acetylcysteine (NAC), zinc, B vitamins, vitamin D, and omega-3 unsaturated fatty acids.

Omega-3 fatty acids are particularly important. The World Federation of Societies of Biological Psychiatry now recommends omega-3s as an adjunctive treatment for mood disorders, with EPA showing the strongest effect for major depression.

Is your psychiatrist recommending changes in your nutrition?

Despite growing evidence of the role nutrition plays in mental health, psychiatrists receive minimal training in nutrition, and most do not provide nutritional counseling as part of their treatment plan. Why? Most mental health providers are unfamiliar with the evidence that shows nutrition’s benefits in mental health. Currently, only 29% of U.S. medical schools teach the recommended goal of 25 hours of nutrition in preclinical years. This lack of training has significant consequences for our patients.

Now that research has demonstrated that poor diet is a risk factor for mental health and that individuals with mental illness are more likely to have poor dietary habits, the case has never been stronger for integrating nutrition into psychiatric training and practice.

New Therapeutic Options

The accumulating evidence doesn't mean that a bowl of salmon and leafy greens will replace Prozac or cognitive-behavioral therapy. More likely, nutritional counseling will be an option that is discussed and recommended along with existing therapies. When I sit with patients who are struggling with depression or anxiety, we discuss their diet and how it could be impacting their mood. Our patients deserve to know what therapeutic options exist and how they can utilize these options to feel better.

When patients change their dietary habits, they often begin to lose weight and feel less depressed This results in them feeling empowered to make other changes in their lives. They become less tolerant of abusive relationships or unhealthy work environments. They realize that addictive patterns can be changed. They grow in self-confidence and self-esteem. These are changes that result in lasting growth and healing.

The brain consumes roughly 20% of the body's energy. If we don't provide it with healthy fuel (i.e. healthy food), our patients may not respond to our treatments. The research is clear, and now it's time for doctors and therapists to empower our patients by providing them with the information they need in order to experience true healing; not just a reduction in their symptoms.

Adan RAH, et al. Nutritional psychiatry: Towards improving mental health by what you eat. Eur Neuropsychopharmacol. 2019;29:1321–1332. https://pubmed.ncbi.nlm.nih.gov/31735529/

Głąbska D, et al. Nutrition and mental health: A review of current knowledge about the impact of diet on mental health. Front Nutr. 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9441951/

Nagamine T. Current state of nutritional psychiatry: A scoping review of randomized controlled trials. World J Methodol. 2025;15(4):104664. https://pmc.ncbi.nlm.nih.gov/articles/PMC12400390/

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